Aviation Safety: Advancements Being Pursued to Improve Airliner
Cabin Occupant Safety and Health (03-OCT-03, GAO-04-33).
Airline travel is one of the safest modes of public
transportation in the United States. Furthermore, there are
survivors in the majority of airliner crashes, according to the
National Transportation Safety Board (NTSB). Additionally, more
passengers might have survived if they had been better protected
from the impact of the crash, smoke, or fire or better able to
evacuate the airliner. As requested, GAO addressed (1) the
regulatory actions that the Federal Aviation Administration (FAA)
has taken and the technological and operational improvements,
called advancements, that are available or are being developed to
address common safety and health issues in large commercial
airliner cabins and (2) the barriers, if any, that the United
States faces in implementing such advancements.
-------------------------Indexing Terms-------------------------
REPORTNUM: GAO-04-33
ACCNO: A08662
TITLE: Aviation Safety: Advancements Being Pursued to Improve
Airliner Cabin Occupant Safety and Health
DATE: 10/03/2003
SUBJECT: Aircraft accidents
Aircraft maintenance
Airline regulation
Safety regulation
Transportation safety
Commercial aviation
Research and development
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GAO-04-33
United States General Accounting Office
GAO Report to the Ranking Democratic Member, Committee on Transportation
and Infrastructure, House of Representatives
October 2003
AVIATION SAFETY
Advancements Being Pursued to Improve Airliner Cabin Occupant Safety and Health
a
GAO-04-33
Highlights of GAO-04-33, a report to the Ranking Democratic Member,
Committee on Transportation and Infrastructure, House of Representatives
Airline travel is one of the safest modes of public transportation in the
United States. Furthermore, there are survivors in the majority of
airliner crashes, according to the National Transportation Safety Board
(NTSB). Additionally, more passengers might have survived if they had been
better protected from the impact of the crash, smoke, or fire or better
able to evacuate the airliner. As requested, GAO addressed (1) the
regulatory actions that the Federal Aviation Administration (FAA) has
taken and the technological and operational improvements, called
advancements, that are available or are being developed to address common
safety and health issues in large commercial airliner cabins and (2) the
barriers, if any, that the United States faces in implementing such
advancements.
This report contains recommendations to FAA to initiate discussions with
NTSB to facilitate the exchange of medical information from accident
investigations and to improve the cost and effectiveness data available
for setting priorities for research on cabin occupant safety and health.
FAA generally agreed with the report's contents and its recommendations.
www.gao.gov/cgi-bin/getrpt?GAO-04-33.
To view the full product, including the scope and methodology, click on
the link above. For more information, contact Gerald Dillingham at (202)
512-2834 or [email protected].
October 2003
AVIATION SAFETY
Advancements Being Pursued to Improve Airliner Cabin Occupant Safety and Health
FAA has taken a number of regulatory actions over the past several decades
to address safety and health issues faced by passengers and flight
attendants in large commercial airliner cabins. GAO identified 18
completed actions, including those that require safer seats, cushions with
better fire-blocking properties, better floor emergency lighting, and
emergency medical kits. GAO also identified 28 advancements that show
potential to further improve cabin safety and health. These advancements
vary in their readiness for deployment. Fourteen are mature, currently
available, and used in some airliners. Among these are inflatable lap seat
belts, exit doors over the wings that swing out on hinges instead of
requiring manual removal, and photo-luminescent floor lighting. The other
14 advancements are in various stages of research, engineering, and
development in the United States, Canada, or Europe.
Several factors have slowed the implementation of airliner cabin safety
and health advancements. For example, when advancements are ready for
commercial use, factors that may hinder their implementation include the
time it takes for (1) FAA to complete the rule-making process, (2) U.S.
and foreign aviation authorities to resolve differences between their
respective requirements, and (3) the airlines to adopt or install
advancements after FAA has approved their use. When advancements are not
ready for commercial use because they require further research, FAA's
processes for setting research priorities and selecting research projects
may not ensure that the limited federal funding for cabin safety and
health research is allocated to the most critical and cost-effective
projects. In particular, FAA does not obtain autopsy and survivor
information from NTSB after it investigates a crash. This information
could help FAA identify and target research to the primary causes of death
and injury. In addition, FAA does not typically perform detailed analyses
of the costs and effectiveness of potential cabin occupant safety and
health advancements, which could help it identify and target research to
the most cost-effective projects.
A Survivable Large Commercial Airliner Accident
Contents
Letter
Results in Brief
Background
Regulatory Actions Have Been Taken and Additional Advancements
Are Under Way to Improve Cabin Occupants' Safety and Health Several
Factors Have Slowed the Implementation of Cabin
Occupant Safety and Health Advancements Conclusions Recommendations for
Executive Action Agency Comments and Our Evaluation
1 3 7
9
19 28 29 30
Appendixes
Appendix I: Appendix II:
Appendix III: Appendix IV:
Appendix V:
Appendix VI:
Objectives, Scope, and Methodology 31
Canada and Europe Cabin Occupant Safety and Health
Responsibilities 35
Canada 35
Europe 36
Summary of Key Actions FAA Has Taken to Improve Airliner
Cabin Safety and Health Since 1984 40
Summaries of Potential Impact Safety Advancements 43 Retrofitting All
Commercial Aircraft with More Advanced Seats 43 Improving the Ability of
Airplane Floors to Hold Seats in an
Accident 48 Preventing Overhead Storage Bin Detachment to Protect
Passengers
in an Accident 50 Child Safety Seats 52 Inflatable Lap Belt Air Bags 56
Summaries of Potential Fire Safety Advancements 58 Fuel Tank Inerting 58
Arc Fault Circuit Breaker 62 Multisensor Detectors 64 Water Mist Fire
Suppression 67 Fire-Safe Fuels 71 Thermal Acoustic Insulation Materials 73
Ultra-Fire-Resistant Polymers 76 Airport Rescue and Fire-Fighting
Operations 79
Summaries of Potential Improved Evacuation Safety Advancements 82
Contents
Passenger Safety Briefings 82 Exit Seat Briefing 84 Photo-luminescent
Floor Track Marking 85 Crewmember Safety and Evacuation Training 88
Acoustic Attraction Signals 90 Smoke Hoods 92 Exit Slide Testing 97
Overwing Exit Doors 100 Next Generation Evacuation Equipment and
Procedures 102 Personal Flotation Devices 104
Appendix VII: Summaries of General Cabin Occupant Safety and Health
Advancements 106 Advanced Warnings of Turbulence 106 Preparations for
In-flight Medical Emergencies 107 Reducing Health Risks to Passengers with
Certain Medical
Conditions 108 Improved Awareness of Radiation Exposure 110 Occupational
Safety and Health Standards for Flight
Attendants 112
Appendix VIII: Application of a Cost Analysis Methodology to Inflatable
Lap Belts 115 Inflatable Lap Belts 115 Summary of Results 115 Methodology
116
Appendix IX: GAO Contacts and Staff Acknowledgments 118 GAO Contacts 118
Staff Acknowledgments 118
Tables Table 1: Table 2: Table 3:
Table 4:
Table 5:
Regulatory Actions Taken by FAA to Improve Cabin
Occupant Safety and Health Since 1984 4
Advancements with Potential to Improve Cabin Occupant
Safety and Health 4
Status of 10 Significant FAA Rules Pertaining to Airliner
Cabin Occupants' Safety and Health, Fiscal Year 1995
through September of Fiscal Year 2003 20
Costs to Equip an Average-sized Airplane in the U.S. Fleet
with Inflatable Lap Seat Belts, Estimated under Alternative
Scenarios (In 2002 discounted dollars) 116
Key Assumptions 117
Contents
Figures Figure 1: Figure 2: Figure 3:
Figure 4:
Figure 5: Figure 6: Figure 7: Figure 8: Figure 9:
Inflatable Lap Belt Air Bag Inflation Sequence
Manual "Self Help" and "Swing Out" Over-Wing Exits
Funding for Federal Research on Cabin Occupant Safety
and Health Issues, by Facility, Fiscal Years 2000-2005
Allocation of Federal Funding for Aircraft Cabin
Occupant Safety and Health Research, Fiscal Year
2003
Coach Seating and Impact Position in Coach Seating
Examples of Child Safety Seats
Water Mist Nozzle and Possible Placement
Fire Insulation Blankets
Flammable Cabin Materials and Small-scale Material Test
Device
11 15
25
26 45 53 68 74
77 80
83
87 90 94
98 102 Figure 10: Airport Rescue and Fire Training
Figure 11: Airline Briefing to Passengers on Safety Briefing Cards
Figure 12: Floor Track Marking Using Photo-luminescent Materials
Figure 13: Test Installation of Acoustic Signalling Device
Figure 14: An Example of a Commercially Available Smoke Hood
Figure 15: Drawing of Possible Emergency Slide Testing of FAA's 747 Test
Aircraft
Figure 16: Airbus' Planned Double Deck Aircraft
Contents
Abbreviations
ACRM Advanced Crew Resource Management
CAMI Civil Aerospace Medical Institute
CRM Crew Resource Management
DGAC Direction Generale de l'Aviation Civile
DOT Department of Transportation
DOT IG Department of Transportation's Inspector General
DVT deep vein thrombosis
EASA European Aviation Safety Agency
FAA Federal Aviation Administration
ICAO International Civil Aviation Organization
JAA European Joint Aviation Authorities
NASA National Aeronautics and Space Administration
NIOSH National Institute of Safety and Health
NTSB National Transportation Safety Board
OSHA Occupational Health and Safety Administration
TRL Technical Readiness Level
TSO Technical Standing Order
This is a work of the U.S. government and is not subject to copyright
protection in the United States. It may be reproduced and distributed in
its entirety without further permission from GAO. However, because this
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copyright holder may be necessary if you wish to reproduce this material
separately.
A
United States General Accounting Office Washington, D.C. 20548
October 3, 2003
The Honorable James L. Oberstar
Ranking Democratic Member
Committee on Transportation and Infrastructure House of Representatives
Dear Mr. Oberstar:
Airline travel is one of the safest modes of public transportation in the
United States, in large part because of the Congress's, Federal Aviation
Administration's (FAA), commercial airlines', aircraft manufacturers', and
airports' combined efforts to prevent commercial airliner accidents.
Furthermore, although a few airliner accidents are catastrophic, there are
survivors in a majority of crashes. According to the National
Transportation Safety Board (NTSB), passengers survived in 19 of the 26
U.S. large commercial airliner accidents that occurred from 1982 through
2001, and in these 19 accidents, over 76 percent of the passengers (1,523
of 1,988) survived.1 Additionally, some of the passengers who died in
these accidents might have survived if they had been better protected from
the impact of the crash or from the effects of smoke and fire and had been
better able to evacuate the airliner. This possibility of survival has led
federal safety officials to focus their efforts not only on preventing
airliner accidents, but also on increasing the chances of surviving them.
Over the past several decades, FAA has been taking regulatory actions to
require the implementation of technological and operational improvements
in cabin occupant safety and health to help increase passengers' chances
of surviving large commercial airliner accidents. In addition, FAA and the
aviation community have been conducting research on new technological and
operational improvements, which we refer to in this report as
advancements, whose implementation could further increase passengers'
chances of survival and improve the safety and health of passengers and
flight attendants. This report discusses regulatory actions that FAA has
taken as well as potential advancements in cabin occupant safety and
health that are (1) currently available but not yet implemented or
installed, and (2) not yet available and subject to additional research to
advance the
1Large, or `transport category' commercial aircraft are defined as those
with a capacity of 30 or more passengers or a load of 7,500 pounds or
more.
technology or lower costs. For implementation of these advancements to
occur, FAA often has to take regulatory action, that is, issuing
regulations or airworthiness directives that require the implementation of
technological and operational improvements in cabin occupant safety and
health. FAA continues to pursue regulatory initiatives as well as conduct
research to improve cabin occupant safety and health. The aviation
community is also attempting to enhance the safety and health of those
traveling and working in airliner cabins through such measures as
providing earlier warnings of turbulence and information on the potential
to develop blood clots on long-distance flights. Besides increasing cabin
occupants' safety and health, these actions and efforts could benefit the
airlines by helping to restore passengers' confidence in the safety of
flight and thereby increasing the demand for air travel, which fell
sharply after September 11, 2001, and still remains below fiscal year 2000
levels.
In response to your request, this report addresses the following
questions: (1) What regulatory actions has FAA taken, and what key
advancements are available or being developed by FAA and others to address
safety and health issues faced by passengers and flight attendants in
large commercial airliner cabins? (2) What factors, if any, slow the
implementation of advancements in cabin occupant safety and health? In
addition, as requested, we identified some factors faced by Canada and
Europe in their efforts to improve cabin occupant safety and health (see
app. II).
To identify the regulatory actions FAA has taken and the key advancements
that are available or being developed to address safety and health issues
facing passengers and flight attendants (cabin occupants), we reviewed the
relevant literature, interviewed FAA officials, and reviewed FAA's
documentation on the regulatory actions it has taken to enhance cabin
occupant safety and health. As part of this effort, FAA officials
identified key regulatory actions that had been completed in this area. In
addition, we interviewed other aviation safety experts in government,
industry, and academia from the United States, Canada, and Europe. (See
app. I for additional information.) Through our reviews and interviews, we
found that FAA's regulatory actions and advancements fell into four broad
categories-three related to safety in the event of a crash and one related
to general cabin occupant safety and health. The regulatory actions and
advancements related to safety in the event of a crash are those actions
taken to (1) minimize injuries from the impact of a crash, (2) prevent
fire or mitigate its effects, and (3) improve the chances and speed of
evacuation. In addition, we discuss the regulatory actions and
advancements FAA has taken to address a fourth category-improving the
safety and health of
cabin occupants. Using the results of our reviews and interviews, we
identified and categorized 28 advancements that are currently available or
being developed, including 5 impact advancements, 8 fire advancements, 10
evacuation advancements, and 5 cabin occupant safety and health
advancements. For each of these advancements, we discuss the background,
research, and regulatory status.2 We also discuss each advancement's
technological readiness for use in the existing commercial airliner fleet
or in newly produced commercial airplanes. To identify factors that have
slowed implementation of airliner cabin occupant safety and health
advancements, we interviewed FAA, NTSB, and industry officials. In
addition, we analyzed documentation from FAA, NTSB, and aviation safety
experts to identify factors relating to key issues within FAA and the
aviation community related to prioritizing and funding research, choosing
advancements for regulatory implementation, and gaining the aviation
community's acceptance of these advancements.
This report does not address cabin air quality because we are doing work
in this area for another congressional requester. In addition, given the
large scope of this review, the report does not focus on safety and health
issues for flight deck crews (pilots and flight engineers) since they face
some unique issues not faced by cabin occupants. It also does not address
aviation security issues, such as hijackings, sabotage, or terrorist
activities.
We conducted our review from January 2002 through September 2003 in
accordance with generally accepted government auditing standards.
Results in Brief FAA has taken a number of key regulatory actions over the
past several decades to improve the safety and health of passengers and
flight attendants in large commercial airliner cabins. We identified 18
such completed regulatory actions that FAA has taken since 1984. Table 1
shows the number of such actions by category and provides an example for
each category of action.
2In identifying 28 advancements, we are not suggesting that these are the
only advancements being pursued, rather that these advancements have been
recognized by aviation safety experts we contacted as offering promise for
improving the safety and health of cabin occupants.
Table 1: Regulatory Actions Taken by FAA to Improve Cabin Occupant Safety
and Health Since 1984
Number of key Category of regulatory action Example actions taken
Minimize injuries from the impact Stronger seats of a crash
Prevent fire or mitigate its effects Fire-blocking seat cushions
Improve the chances and speed Emergency floor lighting of evacuation
Improve the safety and health of Onboard emergency medical cabin occupants
kits
Source: GAO.
We also identified 28 advancements that have the potential to increase the
chances of surviving a commercial airliner crash and to improve the safety
and health of cabin occupants-both passengers and flight attendants. Table
2 shows the number of such advancements by category and provides an
example for each.
Table 2: Advancements with Potential to Improve Cabin Occupant Safety and Health
Number of key Category of advancement Example advancements
Minimize injuries from the impact of Lap seat belts with inflatable air a
crash bags
Prevent fire or mitigate its effects Reduced fuel tank flammability
Improve the chances and speed of Improved passenger safety evacuation
briefings
Improve the safety and health of Advanced warnings of cabin occupants
turbulence
Source: GAO.
These 28 advancements vary in their readiness for deployment. For example,
14 of the technologies are currently available but not yet implemented or
installed. Two of these, preparation for in-flight medical emergencies and
improved insulation, were addressed through separate regulations. These
regulations require airlines to install additional emergency medical
equipment (automatic external defibrillators and enhanced emergency
medical kits) by 2004, replace flammable insulation (metalized Mylar(R))
with improved insulation by 2005, and manufacture
new large commercial airliners with improved (thermal acoustic) insulation
beginning September 2, 2005. Another currently available advancement is in
FAA's rule-making process-retrofitting the entire existing fleet with
significantly stronger seats. These seats, commonly referred to as 16g
seats, for example, can withstand the force of an impact 16 times a
passenger's body weight (16g), rather than 9 times (9g), as currently
required primarily for new generation commercial aircraft.3 For the
remaining 11 currently available advancements, while FAA does not require
their use, some are being used by selected airlines. For example, some
airlines have elected to use inflatable lap seat belts, exit doors over
the wings that swing out on hinges instead of requiring manual removal,
and photo-luminescent floor lighting.4 In addition, some of these
advancements are available for purchase by the flying public, including
smoke hoods and child safety seats certified for use on commercial
airliners. The remaining 14 advancements are in various stages of
research, engineering, and development in the United States, Canada, or
Europe.
Several factors slow the implementation of advancements in cabin occupant
safety and health, including those that are currently available, but have
not yet been implemented or installed and those that require further
research to demonstrate their effectiveness or lower their costs before
they are ready for implementation. For those that are ready, and for which
design and certification standards have been developed, FAA may undertake
the rule-making process to require their implementation. As our prior work
has shown, this process can take years. In addition, FAA and its
international counterparts attempt to reach agreement on, or harmonize,
their requirements for aviation procedures and equipment. The authorities'
current harmonization process has resulted in a backlog, which has slowed
the implementation of several cabin occupant safety and health
advancements. Finally, the airlines must implement the advancements. While
some advancements, such as improved safety briefings, can be implemented
quickly and economically, others, such as retrofitting commercial aircraft
with stronger passenger seats, require time-
3A separate rule-making effort in 1988 required that newly manufactured
aircraft be equipped with stronger, 16g seats; however, it did not require
that the existing U.S. fleet of commercial aircraft be retrofitted with
these seats.
4FAA officials told us that using photo-luminescent lighting is a
different way to meet an existing standard and, therefore, should not be
considered an advancement in safety. However, because photo-luminescent
floor lighting differs from standard floor lighting in that it works
without electricity, some in the aviation community consider it a safety
advancement.
consuming, costly changes. FAA may give the airlines several years to
retrofit their fleets in order to coordinate the change, when possible,
with existing maintenance schedules and allow the airlines to absorb the
associated costs. For advancements that require further research before
they can be considered for use, FAA's multistep process for identifying
potential cabin occupant safety and health research projects and
allocating its limited resources to research projects on the advancements
is hampered by a lack of autopsy and survivor information and cost and
effectiveness data. According to FAA researchers, they have not had
adequate access to autopsy reports and certain survivor information that
NTSB obtains from autopsy reports and interviews with survivors during its
investigations of commercial airliner accidents. This information could
help FAA to identify the principal causes of death and injury and the
major factors affecting survival, and to target research to advancements
addressing these critical causes and factors. NTSB told us that while they
provide large amounts of information on the causes of death and injury in
information they make publicly available, they would consider making this
additional information available to FAA if steps were taken to safeguard
the privacy of victims and survivors. FAA's multistep process for
selecting research projects on advancements includes consideration of such
factors as their potential impact on accident prevention and accident
mitigation; however, it does not include developing comparable estimates
of cost and effectiveness for competing advancements to allow direct
comparisons between them on their potential to reduce injuries and deaths.
We developed a cost analysis methodology to illustrate how FAA could
develop comparable cost estimates, to enhance its current process. The
results of such analyses could be combined with similar estimates of
effectiveness using data available from a variety of sources, including
industry and academia. Using comparable cost and effectiveness data across
the range of advancements could position the agency to choose more
effectively between competing advancements, taking into account estimates
of the number of injuries and fatalities that each advancement might
prevent for the dollars invested. Such cost and effectiveness data would
provide a valuable supplement to FAA's current process for setting
research priorities and selecting projects for funding.
This report contains a recommendation to the Secretary of Transportation
to direct the FAA Administrator to initiate discussions with NTSB to
facilitate the exchange of medical information from accident
investigations. In addition, the report contains a recommendation to the
FAA Administrator to improve the analyses available to decision makers
responsible for setting research priorities and selecting projects for
improving the safety and health of cabin occupants by (1) developing
comparable cost estimates of potential advancements competing for funding
and (2) developing or collecting data on the effectiveness of each
potential advancement to reduce injuries or fatalities. In commenting on a
draft of this report, FAA said that they generally agreed with the
report's contents and its recommendations.
Background The safe travel of U.S. airline passengers is a joint
responsibility of FAA and the airlines in accordance with the Federal
Aviation Act of 1958, as amended, and the Department of Transportation
Act, as amended. To carry out its responsibilities under these acts, FAA
supports research and development; certifies that new technologies and
procedures are safe; undertakes rule-makings, which when finalized form
the basis of federal aviation regulations; issues other guidance, such as
Advisory Circulars; and oversees the industry's compliance with standards
that aircraft manufacturers and airlines must meet to build and operate
commercial aircraft. Aircraft manufacturers are responsible for designing
aircraft that meet FAA's safety standards, and air carriers are
responsible for operating and maintaining their aircraft in accordance
with the standards for safety and maintenance established in FAA's
regulations. FAA, in turn, certifies aircraft designs and monitors the
industry's compliance with the regulations.
FAA's general process for issuing a regulation, or rule, includes several
steps. When the regulation would require the implementation of a
technology or operation, FAA first certifies that the technology or
operation is safe. Then, FAA publishes a notice of proposed rule-making in
the Federal Register, which sets forth the terms of the rule and
establishes a period for the public to comment on it. Next, FAA reviews
the comments by incorporating changes into the rule that it believes are
warranted, and, in some instances, it repeats these steps one or more
times. Finally, FAA publishes a final rule in the Federal Register. The
final rule includes the date when it will go into effect and a time line
for compliance.
Within FAA, the Aircraft Certification Service is responsible for
certifying that technologies are safe, including improvements to cabin
occupant safety and health, generally through the issuance of new
regulations, a finding certifying an equivalent level of safety, or a
special condition when no rule covers the new technology. The
Certification Service is also responsible for taking enforcement action to
ensure the continued safety of aircraft by prescribing standards for
aircraft manufacturers governing the
design, production, and airworthiness of aeronautical products, such as
cabin interiors. The Flight Standards Service is primarily responsible for
certifying an airline's operations (assessing the airline's ability to
carry out its operations and maintain the airworthiness of the aircraft)
and for monitoring the operations and maintenance of the airline's fleet.
FAA conducts research on cabin occupant safety and health issues in two
research facilities, the Mike Monroney Aeronautical Center/Civil Aerospace
Medical Institute in Oklahoma City, Oklahoma, and the William J. Hughes
Technical Center in Atlantic City, New Jersey. The institute focuses on
the impact of flight operations on human health, while the technical
center focuses on improvements in aircraft design, operation, and
maintenance and inspection to prevent accidents and improve survivability.
For the institute or the technical center to conduct research on a
project, an internal FAA requester must sponsor the project. For example,
FAA's Office of Regulation and Certification sponsors much of the two
facilities' work in support of FAA's rule-making activities. FAA also
cooperates on cabin safety research with the National Aeronautics and
Space Administration (NASA), academic institutions, and private research
organizations.
Until recently, NASA conducted research on airplane crashworthiness at its
Langley Research Center in Hampton, Virginia. However, because of internal
budget reallocations and a decision to devote more of its funds to
aviation security, NASA terminated the Langley Center's research on the
crashworthiness of commercial aircraft in 2002. NASA continues to conduct
fire-related research on cabin safety issues at its Glenn Research Center
in Cleveland, Ohio.
NTSB has the authority to investigate civil aviation accidents and
collects data on the causes of injuries and death for the victims of
commercial airliner accidents. According to NTSB, the majority of
fatalities in commercial airliner accidents are attributable to crash
impact forces and the effects of fire and smoke. Specifically, 306 (66
percent) of the 465 fatalities in partially survivable U.S. aviation
accidents from 1983 through 2000 died from impact forces, 131 (28 percent)
died from fire and smoke, and 28 (6 percent) died from other causes.5
5NTSB, Survivability of Accidents Involving Part 121 U.S. Air Carrier
Operations, 1983 Through 2000, NTSB/SR-01/01.
Surviving an airplane crash depends on a number of factors. The space
surrounding a passenger must remain large enough to prevent the passenger
from being crushed. The force of impact must also be reduced to levels
that the passenger can withstand, either by spreading the impact over a
larger part of the body or by increasing the duration of the impact
through an energy-absorbing seat or fuselage. The passenger must be
restrained in a seat to avoid striking the interior of the airplane, and
the seat must not become detached from the floor. Objects within the
airplane, such as debris, overhead luggage bins, luggage, and galley
equipment, must not strike the passenger. A fire in the cabin must be
prevented, or, if one does start, it must burn slowly enough and produce
low enough levels of toxic gases to allow the passenger to escape from the
airplane. If there is a fire, the passenger must not have sustained
injuries that prevent him or her from escaping quickly. Finally, if the
passenger escapes serious injury from impact and fire, he or she must have
access to exit doors and slides or other means of evacuation.
Regulatory Actions Have Been Taken and Additional Advancements Are Under
Way to Improve Cabin Occupants' Safety and Health
Over the past several decades, FAA has taken a number of regulatory
actions designed to improve the safety and health of airline passengers
and flight attendants by (1) minimizing injuries from the impact of a
crash, (2) preventing fire or mitigating its effects, (3) improving the
chances and speed of evacuation, or (4) improving the safety and health of
cabin occupants. (See app. III for more information on the regulatory
actions FAA has taken to improve cabin occupant safety and health.)
Specifically, we identified 18 completed regulatory actions that FAA has
taken since 1984. In addition to these past actions, FAA and others in the
aviation community are pursuing advancements in these four areas to
improve cabin occupant safety and health in the future. We identified and
reviewed 28 such advancements-5 to reduce the impact of a crash on
occupants, 8 to prevent or mitigate fire and its effects, 10 to facilitate
evacuation from aircraft, and 5 to address general cabin occupant safety
and health issues.
Minimizing Injuries from the The primary cause of injury and death for
cabin occupants in an airliner
Impact of a Crash accident is the impact of the crash itself. We
identified two key regulatory actions that FAA has taken to better protect
passengers from impact forces. For example, in 1988, FAA required stronger
passenger seats for newly manufactured commercial airplanes to improve
protection in
survivable crashes.6 These new seats are capable, for example, of
withstanding an impact force that is approximately 16 times a passenger's
body weight (16g), rather than 9 times (9g), and must be tested
dynamically (in multiple directions to simulate crash conditions), rather
than statically (e.g., drop testing to assess the damage from the force of
the weight alone without motion). In addition, in 1992, FAA issued a
requirement for corrective action (airworthiness directive) for designs
found not to meet the existing rules for overhead storage bins on certain
Boeing aircraft, to improve their crashworthiness after bin failures were
observed in the 1989 crash of an airliner in Kegworth, England, and a 1991
crash near Stockholm, Sweden.
We also identified five key advancements that are being pursued to provide
cabin occupants with greater impact protection in the future. These
advancements are either under development or currently available. Examples
include the following:
o Lap seat belts with inflatable air bags: Lap seat belts that contain
inflatable air bags have been developed by private companies and are
currently available to provide passengers with added protection during a
crash. About 1,000 of these lap seat belts have been installed on
commercial airplanes, primarily in the seats facing wall dividers
(bulkheads) to prevent passengers from sustaining head injuries during a
crash. (See fig. 1.)
o Improved seating systems: Seat safety depends on several interrelated
systems operating properly, and, therefore, an airline seat is most
accurately discussed as a system. New seating system designs are being
developed by manufacturers to incorporate new safety and aesthetic designs
as well as meet FAA's 16g seat regulations to better protect passengers
from impact forces. These seating systems would help to ensure that the
seats themselves perform as expected (i.e., they stay attached to the
floor tracks); the space between the seats remains adequate in a crash;
and the equipment in the seating area, such as phones and video screens,
does not increase the impact hazard.
6FAA subsequently proposed, in October 2002, that the 16g seats be put
into the entire existing fleet for both passengers and flight attendants
within 14 years to better protect passengers from impact forces. We
included this proposal in our list of advancements.
o Child safety seats: Child safety seats could provide small children
with additional protection in the event of an airliner crash. NTSB and
others have recommended their use, and FAA has been involved in this issue
for at least 15 years. While it has used its rule-making process to
consider requiring their use, FAA decided not to require child safety
restraints because its analysis found that if passengers were required to
pay full fare for children under the age of 2, some parents would choose
to travel by automobile and, statistically, the chances would increase
that both the children and the adults would be killed. FAA is continuing
to consider a child safety seat requirement.
Figure 1: Inflatable Lap Belt Air Bag Inflation Sequence
Appendix IV contains additional information on the impact advancements we
have identified.
Preventing Fire or Mitigating Its Effect
Fire prevention and mitigation efforts have given passengers additional
time to evacuate an airliner following a crash or cabin fire. FAA has
taken seven key regulatory actions to improve fire detection, eliminate
potential fire hazards, prevent the spread of fires, and better extinguish
them. For example, to help prevent the spread of fire and give passengers
more time to escape, FAA upgraded fire safety standards to require that
seat cushions have fire-blocking layers, which resulted in airlines
retrofitting 650,000 seats over a 3-year period. The agency also set new
low heat/smoke standards for materials used for large interior surfaces
(e.g., sidewalls, ceilings, and overhead bins), which FAA officials told
us resulted in a significant improvement in postcrash fire survivability.
FAA also required smoke detectors to be placed in lavatories and automatic
fire extinguishers in lavatory waste receptacles in 1986 and 1987,
respectively. In addition, the
agency required airlines to retrofit their fleets with fire detection and
suppression systems in cargo compartments, which according to FAA, applied
to over 3,700 aircraft at a cost to airlines of $300 million. To better
extinguish fires when they do start, FAA also required, in 1985, that
commercial airliners carry two Halon fire extinguishers in addition to
other required extinguishers because of Halon's superior fire suppression
capabilities.
We also identified 8 key advancements that are currently available and
awaiting implementation or are under development to provide additional
fire protection for cabin occupants in the future. Examples include the
following:
o Reduced flammability of insulation materials: To eliminate a potential
fire hazard, in May 2000, FAA required that air carriers replace
insulation blankets covered with a type of insulation known as metalized
Mylar(R) on specific aircraft by 2005, after it was found that the
material had ignited and contributed to the crash of Swiss Air Flight
111.7 Over 700 aircraft were affected by this requirement. In addition,
FAA issued a rule in July 2003 requiring that large commercial airplanes
manufactured after September 2, 2005, be equipped with thermal acoustic
insulation designed to an upgraded fire test standard that will reduce the
incidence and intensity of in-flight fires. In addition, after September
2, 2007, newly manufactured aircraft must be equipped with thermal
acoustic materials designed to meet a new standard for burn-through
resistance, providing passengers more time to escape during a postcrash
fire.
o Reduced fuel tank flammability: Flammable vapors in aircraft fuel tanks
can ignite. However, currently available technology can greatly reduce
this hazard by "blanketing" the fuel tank with nonexplosive
nitrogen-enriched air to suppress ("inert") the potential for explosion of
the tank. The U.S. military has used this technology on selected aircraft
for 20 years, but U.S. commercial airlines have not adopted the technology
because of its cost and weight. FAA officials told us that the military's
technology was also unreliable and designed to meet military rather than
civilian airplane design requirements. FAA fire safety experts have
developed a lighter-weight inerting system for center fuel tanks, which is
simpler than the military system and potentially more
7Affected aircraft included Boeing MD-80, MD-88, MD-90, DC-10, and MD-11.
reliable. Reliability of this technology is a major concern for the
aviation industry. According to FAA officials, Boeing and Airbus began
flight testing this technology in July 2003 and August 2003,
respectively.8 In addition, the Air Transport Association (ATA) noted that
inerting is only one prospective component of an ongoing major program for
fuel tank safety, and that it has yet to be justified as feasible and
cost-effective.
o Sensor technology: Sensors are currently being developed to better
detect overheated or burning materials. According to FAA and the National
Institute of Standards and Technology, many current smoke and fire
detectors are not reliable. For example, a recent FAA study reported at
least one false alarm per week in cargo compartment fire detection
systems. The new detectors are being developed by Airbus and others in
private industry to reduce the number of false alarms. In addition, FAA is
developing standards that would be used to approve new, reduced false
alarm sensors. NASA is also developing new sensors and detectors.
o Water mist for extinguishing fires: Technology has been under
development for over two decades to dispense water mist during a fire to
protect passengers from heat and smoke and prevent the spread of fire in
the cabin. The most significant development effort has been made by a
European public-private consortium, FIREDETEX, with over 5 million euros
of European Community funding and a total project cost of over 10 million
euros (over 10 million U.S. dollars). The development of this system was
prompted, in part, by the need to replace Halon, when it was determined
that this main firefighting agent used in fire extinguishers aboard
commercial airliners depletes ozone in the atmosphere.
Appendix V contains additional information on advancements that address
fire prevention and mitigation.
Improving the Chances and Enabling passengers to evacuate more quickly
during an emergency has
Speed of Evacuation saved lives. Over the past two decades, FAA has
completed regulatory action on the following six key requirements to help
speed evacuations:
8According to FAA, Boeing is flight testing a system similar to the FAA
design, and Airbus is flight testing the FAA system in an A320. Boeing
announced that it would begin installing inerting systems similar to the
FAA design in their 747s in 2005.
o Improve access to certain emergency exits, such as those generally
smaller exits above the wing, by providing an unobstructed passageway to
the exit.
o Install public address systems that are independently powered and can
be used for at least 10 minutes.
o Help to ensure that passengers in the seats next to emergency exits are
physically and mentally able to operate the exit doors and assist other
passengers in emergency evacuations.
o Limit the distance between emergency exits to 60 feet.
o Install emergency lighting systems that visually identify the emergency
escape path and each exit.
o Install fire-resistant emergency evacuation slides.
We also identified 10 advancements that are either currently available but
awaiting implementation or require additional research that could lead to
improved aircraft evacuation, including the following:
o Improved passenger safety briefings: Information is available to the
airlines on how to develop more appealing safety briefings and safety
briefing cards so that passengers would be more likely to pay attention to
the briefings and be better prepared to evacuate successfully during an
emergency. Research has found that passengers often ignore the oral
briefings and do not familiarize themselves with the safety briefing
cards. FAA has requested that air carriers explore different ways to
present safety information to passengers, but FAA regulates only the
content of briefings. The presentation style of safety briefings is left
up to air carriers.
o Over-wing exit doors: Exit doors located over the wings of some
commercial airliners have been redesigned to "swing out" and away from the
aircraft so that cabin occupants can exit more easily during an emergency.
Currently, the over-wing exit doors on most U.S. commercial airliners are
"self help" doors and must be lifted and stowed by a passenger, which can
impede evacuation. (See fig. 2.) The redesigned doors are now used on
new-generation B-737 aircraft operated by one U.S. and most European
airlines. FAA does not currently require the use of over-wing exit doors
that swing out because the exit doors that are
removed manually meet the agency's safety standards. However, FAA is
working with the Europeans to develop common requirements for the use of
this type of exit door.
o Audio attraction signals: The United Kingdom's Civil Aviation Authority
and the manufacturer are testing audio attraction signals to determine
their usefulness to passengers in locating exit doors during an
evacuation. These signals would be mounted near exits and activated during
an emergency. The signals would help the passengers find the nearest exit
even if lighting and exit signs were obscured by smoke.
Figure 2: Manual "Self Help" and "Swing Out" Over-Wing Exits
Appendix VI contains additional information on advancements to improve
aircraft emergency evacuations.
Improving the Safety and Passengers and flight attendants can face a range
of safety and health
Health of Cabin Occupants effects while aboard commercial airliners. We
identified three key actions taken by FAA to help maintain the safety and
health of passengers and the
cabin crew during normal flight operations.9 For example, to prevent
passengers from being injured during turbulent conditions, FAA initiated
the Turbulence Happens campaign in 2000 to increase public awareness of
the importance of wearing seatbelts. The agency has advised the airlines
to warn passengers to fasten their seatbelts when turbulence is expected,
and the airlines generally advise or require passengers to keep their seat
belts fastened while seated to help avoid injuries from unexpected
turbulence. FAA has also required the airlines to equip their fleets with
emergency medical kits since 1986. In addition, Congress banned smoking on
most domestic flights in 1990.
We also identified five advancements that are either currently available
but awaiting implementation or require additional research that could lead
to an improvement in the health of passengers and flight attendants in the
future.
o Automatic external defibrillators: Automatic external defibrillators
are currently available for use on some commercial airliners if a
passenger or crew member requires resuscitation. In 1998, the Congress
directed FAA to assess the need for the defibrillators on commercial
airliners. On the basis of its findings, the agency issued a rule
requiring that U.S. airlines equip their aircraft with automatic external
defibrillators by 2004. According to ATA, most airlines have already done
so.
o Enhanced emergency medical kits: In 1998, the Congress directed FAA to
collect data for 1 year on the types of in-flight medical emergencies that
occurred to determine if existing medical kits should be upgraded. On the
basis of the data collected, FAA issued a rule that required the contents
of existing emergency medical kits to be expanded to deal with a broader
range of emergencies. U.S. commercial airliners are required to carry
these enhanced emergency medical kits by 2004. Most U.S. airlines have
already completed this upgrade, according to ATA.
o Advance warning of turbulence: New airborne weather radar and other
technologies are currently being developed and evaluated to improve the
detection of turbulence and increase the time available to cabin occupants
to avert potential injuries. FAA's July 2003 draft strategic plan
established a performance target of reducing injuries to cabin occupants
caused by turbulence. To achieve this objective, FAA plans to continue
9As noted, actions taken to improve cabin air quality will be discussed in
another report.
evaluating new airborne weather radars and other technologies that broadly
address weather issues, including turbulence. In addition, the draft
strategic plan set a performance target of reducing serious injuries
caused by turbulence by 33 percent by fiscal year 2008--using the average
for fiscal years 2000 through 2002 of 15 injuries per year as the baseline
and reducing this average to no more than 10 per year.
o Improve awareness of radiation exposure: Flight attendants and
passengers who fly frequently can be exposed to higher levels of radiation
on a cumulative basis than the general public. High levels of radiation
have been linked to an increased risk of cancer and potential harm to
fetuses. To help passengers and crew members estimate their past and
future radiation exposure levels, FAA developed a computer model, which is
publicly available on its Web site
http://www.jag.cami.jccbi.gov/cariprofile.asp. However, the extent to
which flight attendants and frequent flyers are aware of cosmic
radiation's risks and make use of FAA's computer model is unclear. Agency
officials told us that they plan to install a counter capability on its
Civil Aerospace Medical Institute Web site to track the number of visits
to its aircrew and passenger health and safety Web site. FAA also plans to
issue an Advisory Circular by early next year, which incorporates the
findings of a just completed FAA report, "What Aircrews Should Know About
Their Occupational Exposure to Ionizing Radiation." This Advisory Circular
will include recommended actions for aircrews and information on solar
flare event notification of aircrews. In contrast, airlines in Europe
abide by more stringent requirements for helping to ensure that cabin and
flight crew members do not receive excessive doses of radiation from
performing their flight duties during a given year. For example, in May
1996, the European Union issued a directive for workers, including air
carrier crew members (cabin and flight crews) and the general public, on
basic safety and health protections against dangers arising from ionizing
radiation. This directive set dose limits and required air carriers to (1)
assess and monitor the exposure of all crew members to avoid exceeding
exposure limits, (2) work with those individuals at risk of high exposure
levels to adjust their work or flight schedules to reduce those levels,
and (3) inform crew members of the health risks that their work involves
from exposure to radiation. It also required airlines to work with female
crew members, when they announce a pregnancy, to avoid exposing the fetus
to harmful levels of radiation. This directive was binding for all
European Union member states and became effective in May 2000.
o Improved awareness of potential health effects related to flying: Air
travel may exacerbate some medical conditions. Of particular concern is a
condition known as Deep Vein Thrombosis (DVT), or travelers' thrombosis,
in which blood clots can develop in the deep veins of the legs from
extended periods of inactivity. In a small percentage of cases, the clots
can break free and travel to the lungs, with potentially fatal results.
Although steps can be taken to avoid or mitigate some travel-related
health effects, no formal awareness campaigns have been initiated by FAA
to help ensure that this information reaches physicians and the traveling
public. The Aerospace Medical Association's Web site
http://www.asma.org/publication.html includes guidance for physicians to
use in advising passengers with preexisting medical conditions on the
potential risks of flying, as well as information for passengers with such
conditions to use in assessing their own potential risks.
See appendix VII for additional information on health-related advances.
Advancements Vary in Their Readiness for Deployment
The advancements being pursued to improve the safety and health of cabin
occupants vary in their readiness for deployment. For example, of the 28
advancements we reviewed, 14 are mature and currently available. Two of
these, preparation for in-flight medical emergencies and the use of new
insulation, were addressed through regulations. These regulations require
airlines to install additional emergency medical equipment (automatic
external defibrillators and enhanced emergency medical kits) by 2004,
replace flammable insulation covering (metalized Mylar(R)) on specific
aircraft by 2005, and manufacture new large commercial airliners that use
a new type of insulation meeting more stringent flammability test
standards after September 2, 2005. Another advancement is currently in the
rule-making process-retrofitting the existing fleet with stronger 16g
seats. The remaining 11 advancements are available, but are not required
by FAA. For example, some airlines have elected to use inflatable lap seat
belts and exit doors over the wings that swing out instead of requiring
manual removal, and others are using photo-luminescent floor lighting in
lieu of or in combination with traditional electrical lighting. Some of
these advancements are commercially available to the flying public,
including smoke hoods and child safety seats certified for use on
commercial airliners. The remaining 14 advancements are in various stages
of research, engineering, and development in the United States, Canada, or
Europe.
Several Factors Have Slowed the Implementation of Cabin Occupant Safety
and Health Advancements
Several factors have slowed the implementation of airliner cabin occupant
safety and health advancements in the United States. When advancements are
available for commercial use but not yet implemented or installed, their
use may be slowed by the time it takes (1) for FAA to complete the
rule-making process,10 which may be required for an advancement to be
approved for use but may take many years; (2) for U.S. and foreign
aviation authorities to resolve differences between their respective cabin
occupant safety and health requirements; and (3) for the airlines to adopt
or install advancements after FAA has approved their use, including the
time required to schedule an advancement's installation to coincide with
major maintenance cycles and thereby minimize the costs associated with
taking an airplane out of service. When advancements are not ready for
commercial use because they need further research to develop their
technologies or reduce their costs, their implementation may be slowed by
FAA's multistep process for identifying advancements and allocating its
limited resources to research on potential advancements. FAA's multistep
process is hampered by a lack of autopsy and survivor information from
past accidents and by not having cost and effectiveness data as part of
the decision process. As a result, FAA may not be identifying and funding
the most critical or cost-effective research projects.
FAA's Rule-making Process to Require Advancements Can Be Lengthy
Once an advancement has been developed, FAA may require its use, but
significant time may be required before the rule-making process is
complete. One factor that contributes to the length of this process is a
requirement for cost-benefit analyses to be completed. Time is
particularly important when safety is at stake or when the pace of
technological development exceeds the pace of rule-making. As a result,
some rules may need to be developed quickly to address safety issues or to
guide the use of new technologies. However, rules must also be carefully
considered before being finalized because they can have a significant
impact on individuals, industries, the economy, and the environment.
External pressures-such as political pressure generated by highly
publicized accidents, recommendations by NTSB, and congressional
mandates-as well as internal pressures, such as changes in management's
emphasis, continue to add to and shift the agency's priorities.
10ATA noted that, for those technologies that are ready, FAA must develop
design and certification standards before undertaking the rule-making
process to require their implementation.
The rule-making process can be long and complicated and has delayed the
implementation of some technological and operational safety improvements,
as we reported in July 2001.11 In that report, we reviewed 76 significant
rules in FAA's workload for fiscal years 1995 through 2000-10 of the 76
were directly related to improving the safety and health of cabin
occupants.12 Table 3 details the status or disposition of these 10 rules.
The shortest rule-making action took 1 year, 11 months (for child
restraint systems), and the longest took 10 years, 1 month (for the type
and number of emergency exits). However, one proposed rule was still
pending after 15 years, while three others were terminated or withdrawn
after 9 years or more. Of the 76 significant rules we reviewed, FAA
completed the rule-making process for 29 of them between fiscal year 1995
and fiscal year 2000, in a median time of about 2 1/2 years to proceed
from formal initiation of the rule-making process through publication of
the final rule; however, FAA took 10 years or more to move from formal
initiation of the rule-making process through publication of the final
rule for 6 of these 29 rules.
Table 3: Status of 10 Significant FAA Rules Pertaining to Airliner Cabin
Occupants' Safety and Health, Fiscal Year 1995 through September of Fiscal
Year 2003
Rule title Initiation Time Status/disposition
datea elapsed
Flight attendant 2/04/86 9 years, 8 Terminated/withdrawn
requirements months 6/06/96
Type and number of 10 years, 1
passenger emergency exits 10/15/86 month Final rule published on
required in transport 11/08/96
category airplanes
Airworthiness standards; 11 years, 1
occupant protection 5/29/87 month Terminated/withdrawn
standards for commuter 6/30/98
category airplanes
Retrofit of improved seats 15 years, 6
in air carrier transport 1/26/88 months Pending
category airplanes
5 years, 9
Child restraint systems 5/30/90 months Terminated/withdrawn
2/13/96
11U.S. General Accounting Office, Aviation Rule-making: Further Reform Is
Needed to Address Long-standing Problems, GAO-01-821 (Washington, D.C.:
July 9, 2001).
12Under Executive Order 12866, federal agencies and the Office of
Management and Budget (OMB) categorize proposed and final rules in terms
of their potential impact on the economy and the industry affected. The
Order defines a regulatory action as "significant" if it, among other
things, has an annual impact on the economy of $100 million or more and
adversely affects the economy in a material way. To measure the overall
impact of the 1998-rule-making reforms, through discussions with FAA
officials, we created a database of 76 significant rules. These rules
constituted the majority (about 83 percent) of FAA's significant rule
workload from fiscal year 1995 through fiscal year 2000.
(Continued From Previous Page)
Rule title Initiation Time Status/disposition
datea elapsed
Revised access to Type III 9 years, 5 Withdrawn
exits 10/30/92 months
5/03/02
Child restraint systems 7/18/94 1 year 11 Final rule published on
months 6/04/96
Child restraint systems 4/07/97 6 years, 3 Pending
months
2 years, 8
Emergency medical equipment 10/5/98 months Final rule published on
6/12/01
Improved flammability
standards for thermal 4 years, 7 Final rule published on
acoustic insulation 12/04/98 months July 31, 2003
materials in transport
category aircraft
Source: GAO analysis of FAA data.
Note: In commenting on a draft of this report, FAA noted that examining
the years elapsed from the initiation date of the rule to disposition can
be unfair to some actions and that many of the delays were not the fault
of FAA.
aInitiation dates were identified in FAA's rule-making information system
as GAO reported in July 2001. This was the only source for data on the
agency's internal milestones, including "initiation date."
Differences in U.S. and Foreign Requirements Can Hamper Adoption of
Advancements
FAA and its international counterparts, such as the European Joint
Aviation Authorities (JAA), impose a number of requirements to improve
safety. At times, these requirements differ, and efforts are needed to
reach agreement on procedures and equipment across country borders. In the
absence of such agreements, the airlines generally must adopt measures to
implement whichever requirement is more stringent. In 1992, FAA and JAA
began harmonizing their requirements for (1) the design, manufacture,
operation, and maintenance of civil aircraft and related product parts;
(2) noise and emissions from aircraft; and (3) flight crew licensing.
Harmonizing the U.S. Federal Aviation Regulations with the European Joint
Aviation Regulations is viewed by FAA as its most comprehensive long-term
rule-making effort and is considered critical to ensuring common safety
standards and minimizing the economic burden on the aviation industry that
can result from redundant inspection, evaluation, and testing
requirements.
According to both FAA and JAA, the process they have used to date to
harmonize their requirements for commercial aircraft has not effectively
prioritized their joint recommendations for harmonizing U.S. and European
aviation requirements, and led to many recommendations going unpublished
for years. This includes a backlog of over 130 new rule-making efforts.
The slowness of this process led the United States and Europe to develop a
new rule-making process to prioritize safety initiatives, focus the
aviation industry's and their own limited resources, and establish
limitations on rule-making capabilities. Accordingly, in March 2003, FAA
and JAA developed a draft joint "priority" rule-making list; collected and
considered industry input; and coordinated with FAA's, JAA's, and
Transport Canada Civil Aviation's management. This effort has resulted in
a rule-making list of 26 priority projects. In June 2003, at the 20th
Annual JAA/FAA International Conference, FAA, JAA, and Transport Canada
Civil Aviation discussed the need to, among other things, support the
joint priority rule-making list and to establish a cycle for updating
it-to keep it current and to provide for "pop-up," or unexpected,
rule-making needs. FAA and JAA discussed the need to prioritize
rule-making efforts to efficiently achieve aviation safety goals; that
they would work from a limited agreed-upon list for future rule-making
activities; and that FAA and the European Aviation Safety Agency, which is
gradually replacing JAA, should continue with this approach.
In the area of cabin occupant safety and heath, some requirements have
been harmonized, while others have not. For example, in 1996, JAA changed
its rule on floor lighting to allow reflective, glow-in-the-dark material
to be used rather than mandating the electrically powered lighting that
FAA required. The agency subsequently permitted the use of this material
for floor lighting. In addition, FAA finalized a rule in July 2003 to
require a new type of insulation designed to delay fire burning though the
fuselage into the cabin during an accident. JAA favors a performance-based
standard that would specify a minimum delay in burn-through time, but
allow the use of different technologies to achieve the standard. FAA
officials said that the agency would consider other technologies besides
insulation to achieve burn-through protection but that it would be the
responsibility of the applicant to demonstrate that the technology
provided performance equivalent to that stipulated in the insulation rule.
JAA officials told us that these are examples of the types of issues that
must be resolved when they work to harmonize their requirements with
FAA's. These officials added that this process is typically very time
consuming and has allowed for harmonizing about five rules per year.
Significant Time May Be Needed to Implement Advancements Once They Are
Required, but Some May Enhance Airlines' Competitiveness
After an advancement has been developed, shown to be beneficial,
certified, and required by FAA, the airlines or manufacturers need time to
implement or install the advancement.13 FAA generally gives the airlines
or manufacturers a window of time to comply with its rules. For example,
FAA gave air carriers 5 years to replace metalized Mylar(R) insulation on
specific aircraft with a less flammable insulation type, and FAA's
proposed rule-making on 16g seats would give the airlines 14 years to
install these seats in all existing commercial airliners. ATA officials
told us that this would require replacement of 496,000 seats.
The airline industry's recent financial hardships may also delay the
adoption of advancements. Recently, two major U.S. carriers filed for
bankruptcy,14 and events such as the war in Iraq have reduced passenger
demand and airline revenues below levels already diminished by the events
of September 11, 2001, and the economic downturn. Current U.S. demand for
air travel remains below fiscal year 2000 levels. As a result, airlines
may ask for exemptions from some requirements or extensions of time to
install advancements.
While implementing new safety and health advancements can be costly for
the airlines, making these changes could improve the public's confidence
in the overall safety of air travel. In addition, some aviation experts in
Europe told us that health-related cabin improvements, particularly
improvements in air quality, are of high interest to Europeans and would
likely be used in the near future by some European air carriers to set
themselves apart from their competitors.
13According to ATA, even if a technology is available in the marketplace,
it may not be adopted by the airlines until it has been certified by
FAA--ensuring that "improvements" do not inadvertently compromise overall
safety of the aircraft.
14One of these U.S. carriers is no longer in bankruptcy.
FAA's Multistep Process for Allocating Limited Resources to Research
Projects Is Hampered by Lack of Autopsy and Survivor Information and Cost
and Effectiveness Data
Federal Research on Aircraft Cabin Occupant Safety and Health Issues
For fiscal year 2003, FAA and NASA allocated about $16.2 million to cabin
occupant safety and health research. FAA's share of this research
represented $13.1 million, or about 9 percent of the agency's Research,
Engineering, and Development budget of $148 million for fiscal year 2003.
Given the level of funding allocated to this research effort, it is
important to ensure that the best research projects are selected. However,
FAA's processes for setting research priorities and selecting projects for
further research are hampered by data limitations. In particular, FAA
lacks certain autopsy and survivor information from aircraft crashes that
could help it identify and target research to the most important causes of
death and injury in an airliner crash. In addition, for the proposed
research projects, the agency does not (1) develop comparable cost data
for potential advancements or (2) assess their potential effectiveness in
minimizing injuries or saving lives. Such cost and effectiveness data
would provide a valuable supplement to FAA's current process for setting
research priorities and selecting projects for funding.
Both FAA and NASA conduct research on aircraft cabin occupant safety and
health issues. The Civil Aeromedical Institute (CAMI) and the Hughes
Technical Center are FAA's primary facilities for conducting research in
this area. In addition, two facilities at NASA, the Langley and Glenn
research centers, have also conducted research in this area. As figure 3
shows, federal funding for this research since fiscal year 2000, reached a
high in fiscal year 2002, at about $17 million, and fell to about $16.2
million in fiscal year 2003. The administration's proposal for fiscal year
2004 calls for a further reduction to $15.9 million. This funding covers
the expenses of researchers at these facilities and of the contracts they
may have with others to conduct research. In addition, NASA recently
decided to end its crash research at Langley and to close a drop test
facility that it operates in Hampton, Virginia.
Figure 3: Funding for Federal Research on Cabin Occupant Safety and Health
Issues, by Facility, Fiscal Years 2000-2005
Note: FAA Hughes Technical Center data includes work in fire-safe fuels,
fuel-tank inerting, arc fault circuit breakers, and airport rescue and
fire-fighting operations.
In fiscal year 2003, FAA and NASA both supported research projects,
including aircraft impact, fire, evacuation, and health. As figure 4
shows, most of the funding for cabin occupant safety and health research
has gone to fire-related projects.
FAA Research Selection Process Hampered by Lack of Autopsy and Survivor
Information and Cost and Effectiveness Analyses
Figure 4: Allocation of Federal Funding for Aircraft Cabin Occupant Safety
and Health Research, Fiscal Year 2003
Note: Sum of bars exceeds $16.2 million due to rounding. FAA Technical
Center data includes work in fire-safe fuels, fuel-tank inerting, arc
fault circuit breakers, and airport rescue and fire-fighting operations
To establish research priorities and select projects to fund, FAA uses a
multistep process. First, within each budget cycle, a number of Technical
Community Representative Group subcommittees from within FAA generate
research ideas. Various subcommittees have responsibility for identifying
potential safety and health projects, including subcommittees on crash
dynamics, fire safety, structural integrity, passenger evacuation,
aeromedical, and fuel safety. Each subcommittee proposes research projects
to review committees, which prioritize the projects. The projects are
considered and weighted according to the extent to which they address (1)
accident prevention, (2) accident survival, (3) external requests for
research, (4) internal requests for research, and (5) technology research
needs. In addition, the cost of the proposed research is considered before
arriving at a final list of projects. The prioritized list is then
considered by the Program Planning Team, which reviews the projects from a
policy perspective.
Although the primary causes of death and injury in commercial airliner
crashes are known to be impact, fire, and impediments to evacuation, FAA
does not have as detailed an understanding as it would like of the
critical factors affecting survival in a crash. According to FAA
officials, obtaining a more detailed understanding of these factors would
assist them in setting research priorities and in evaluating the relative
importance of competing research proposals. To obtain a more detailed
understanding of the critical factors affecting survival, FAA believes
that it needs additional information from passenger autopsies and from
passengers who survived. With this information, FAA could then regulate
safety more effectively, airplane and equipment designers could build
safer aircraft, including cabin interiors, and more passengers could
survive future accidents as equipment became safer.
While FAA has independent authority to investigate commercial airliner
crashes, NTSB generally controls access to the accident investigation site
in pursuit of its primary mission of determining the cause of the crash.
When NTSB concludes its investigation, it returns the airplane to its
owner and keeps the records of the investigation, including the autopsy
reports and the information from survivors that NTSB obtains from medical
authorities and through interviews or questionnaires. NTSB makes summary
information on the crashes publicly available on its Web site, but
according to the FAA researchers, this information is not detailed enough
for their needs. For example, the researchers would like to develop a
complete autopsy database that would allow them to look for common trends
in accidents, among other things. In addition, the researchers would like
to know where survivors sat on the airplane, what routes they took to
exit, what problems they encountered, and what injuries they sustained.
This information would help the researchers analyze factors that might
have an impact on survival. According to the NTSB's Chief of the Survival
Factors Division in the Office of Aviation Safety, NTSB provides
information on the causes of death and a description of injuries in the
information they make publicly available. In addition, although medical
records and autopsy reports are not made public, interviews with and
questionnaires from survivors are available from the public docket.
NTSB's Medical Officer was unaware of any formal requests from the FAA for
the NTSB to provide them with copies of this type of information, although
the FAA had previously been invited to review such information at NTSB
headquarters. He added that the Board would likely consider a formal
request from FAA for copies of autopsy reports and certain survivor
records, but that it was also likely that the FAA would have to assure
NTSB
that the information would be appropriately safeguarded. According to FAA
officials, close cooperation between the NTSB and the FAA is needed for
continued progress in aviation safety.
Besides lacking detailed information on the causes of death and injury,
FAA does not develop data on the cost to implement advancements that are
comparable for each, nor does it assess the potential effectiveness of
each advancement in reducing injuries and saving lives. Specifically, FAA
does not conduct cost-benefit analyses as part of its multistep process
for setting research priorities. Making cost estimates of competing
advancements would allow direct comparisons across alternatives, which,
when combined with comparable estimates of effectiveness, would provide
valuable supplemental information to decision makers when setting research
priorities. FAA considers its current process to be appropriate and
sufficient. In commenting on a draft of this report, FAA noted that it is
very difficult to develop realistic cost data for advancements during the
earliest stages of research. The agency cautioned that if too much
emphasis is placed on cost/benefit analyses, potentially valuable research
may not be undertaken. Recognizing that it is less difficult to develop
cost and effectiveness information as research progresses, we are
recommending that FAA develop and use cost and effectiveness analyses to
supplement its current process. At later stages in the development
process, we found that this information can be developed fairly easily
through cost and effectiveness analyses using currently available data.
For example, we performed an analysis of the cost to implement inflatable
lap seat belts using a cost analysis methodology we developed (see app.
VIII). This analysis allowed us to estimate how much this advancement
would cost per airplane and per passenger trip. Such cost analyses could
be combined with similar analyses of effectiveness to identify the most
cost-effective projects, based on their potential to minimize injuries and
reduce fatalities. Potential sources of effectiveness data include FAA,
academia, industry, and other aviation authorities.
Conclusions Although FAA and the aviation community are pursuing a number
of advancements to enhance commercial airliners' cabin occupant safety and
health, several factors have slowed their implementation. For example, for
advancements that are currently available but are not yet implemented or
installed, progress is slowed by the length of time it takes for FAA to
complete its rule-making process, for the U.S and foreign countries to
agree on the same requirements, and for the airlines to actually install
the advancements after FAA has required them. In addition, FAA's multistep
process for identifying potential cabin occupant safety and health
research projects and allocating its limited research funding is hampered
by the lack of autopsy and survivor information from airliner crashes and
by the lack of cost and effectiveness analysis. Given the level of funding
allocated to cabin occupant safety and health research, it is important
for FAA to ensure that this funding is targeting the advancements that
address the most critical needs and show the most promise for improving
the safety and health of cabin occupants. However, because FAA lacks
detailed autopsy and survivor information, it is hampered in its ability
to identify the principal causes of death and survival in commercial
airliner crashes. Without an agreement with the National Transportation
Safety Board (NTSB) to receive detailed autopsy and survivor information,
FAA lacks information that could be helpful in understanding the factors
that contribute to surviving a crash. Furthermore, because FAA does not
develop comparable estimates of cost and effectiveness of competing
research projects, it cannot ensure that it is funding those technologies
with the most promise of saving lives and reducing injuries. Such cost and
effectiveness data would provide a valuable supplement to FAA's current
process for setting research priorities and selecting projects for
funding. To facilitate FAA's development of comparable cost data across
advancements, we developed a cost analysis methodology that could be
combined with a similar analysis of effectiveness to identify the most
cost-effective projects. Using comparable cost and effectiveness data
across the range of advancements would position the agency to choose more
effectively between competing advancements, taking into account estimates
of the number of injuries and fatalities that each advancement might
prevent for the dollars invested. In turn, FAA would have more assurance
that the level of funding allocated to this effort maximizes the safety
and health of the traveling public and the cabin crew members who serve
them.
Recommendations for Executive Action
To provide FAA decision makers with additional data for use in setting
priorities for research on cabin occupant safety and health and in
selecting competing research projects for funding, we recommend that the
Secretary of Transportation direct the FAA Administrator to
o initiate discussions with the National Transportation Safety Board in
an effort to obtain the autopsy and survivor information needed to more
fully understand the factors affecting survival in a commercial airliner
crash and
o supplement its current process by developing and using comparable
estimates of cost and effectiveness for each cabin occupant safety and
health advancement under consideration for research funding.
Agency Comments and We provided copies of a draft of this report to the
Department of Transportation for its review and comment. FAA generally
agreed with the
Our Evaluation report's contents and its recommendations. The agency
provided us with oral comments, primarily technical clarifications, which
we have incorporated as appropriate.
As agreed with your office, unless you publicly announce its contents
earlier, we plan no further distribution of this report until 10 days
after the
date of this letter. At that time, we will send copies to the appropriate
congressional committees; the Secretary of Transportation; the
Administrator, FAA; and the Chairman, NTSB. We will also make copies
available to others upon request. In addition, this report is also
available at
no charge on GAO's Web site at http://www.gao.gov.
Contacts and staff acknowledgements for this report are included in
appendix IX. If you or your staff have any questions, please contact me or
Glen Trochelman at (202) 512-2834
Sincerely yours,
Gerald L. Dillingham
Director, Physical Infrastructure Issues
Appendix I
Objectives, Scope, and Methodology
As requested by the Ranking Democratic Member, House Committee on
Transportation and Infrastructure, we addressed the following questions:
(1) What regulatory actions has the Federal Aviation Administration (FAA)
taken, and what key advancements are available or being developed by FAA
and others to address safety and health issues faced by passengers and
flight attendants in large commercial airliner cabins? (2) What factors,
if any, slow the implementation of advancements in cabin occupant safety
and health? In addition, as requested, we identified some factors
affecting efforts by Canada and Europe to improve cabin occupant safety
and health.
The scope of our report includes the cabins of large commercial aircraft
(those that carry 30 or more passengers) operated by U.S. domestic
commercial airlines and addresses the safety and health of passengers and
flight attendants from the time they board the airliner until they
disembark under normal operational conditions or emergency situations.
This report identifies cabin occupant safety and health advancements
(technological or operational improvements) that could be implemented,
primarily through FAA's rule-making process. Such improvements include
technological changes designed to increase the overall safety of
commercial aviation as well as changes to enhance operational safety. The
report does not include information on the flight decks of large
commercial airliners or safety and health issues affecting flight deck
crews (pilots and flight engineers), because they face some issues not
faced by cabin occupants. It also does not address general aviation and
corporate aircraft or aviation security issues, such as hijackings,
sabotage, or terrorist activities.
To identify regulatory actions that FAA has taken to address safety and
health issues faced by passengers and flight attendants in large
commercial airliner cabins, we interviewed and collected documentation
from U.S. federal agency officials on major safety and health efforts
completed by FAA. The information we obtained included key dates and
efforts related to cabin occupant safety and health, such as rule-makings,
airworthiness directives, and Advisory Circulars.
To identify key advancements that are available or are being developed by
FAA and others to address safety and health issues faced by passengers and
flight attendants in large commercial airliner cabins, we consulted
experts (1) to help ensure that we had included the advancements holding
the most promise for improving safety and health; and (2) to help us
structure an evaluation of selected advancements (i.e., confirm that we
had included the critical benefits and drawbacks of the potential
advancements) and develop a descriptive analysis for them, where
appropriate, including their
Appendix I
Objectives, Scope, and Methodology
benefits, costs, technology readiness levels, and regulatory status. In
addition, we interviewed and obtained documentation from federal agency
officials and other aviation safety experts at the Federal Aviation
Administration (including its headquarters in Washington, D.C.; Transport
Airplane Directorate in Renton, Washington; William J. Hughes Technical
Center in Atlantic City, New Jersey; and Mike Monroney Aeronautical
Center/Civil Aerospace Medical Institute in Oklahoma City, Oklahoma);
National Transportation Safety Board; National Aeronautics and Space
Administration (NASA); Air Transport Association; Regional Airline
Association; International Air Transport Association; Aerospace Industries
Association; Aerospace Medical Association; Flight Safety Foundation,
Association of Flight Attendants; Boeing Commercial Airplane Group;
Airbus; Cranfield University, United Kingdom; University of Greenwich,
United Kingdom; National Aerospace Laboratory, Netherlands; Joint Aviation
Authorities, Netherlands; Civil Aviation, Netherlands; Civil Aviation
Authority, United Kingdom; RGW Cherry and Associates; Air Accidents
Investigations Branch, United Kingdom; Syndicat National du Personnel
Navigant Commercial (French cabin crew union) and ITF Cabin Crew
Committee, France; BEA (comparable to the U.S. NTSB), France; and the
Direction Generale de l'Aviation Civile (DGAC), FAA's French counterpart.
To describe the status of key advancements that are available or under
development, we used NASA's technology readiness levels (TRL). These
levels form a system for ranking the maturity of particular technologies
and are as follows:
o TRL 1: Basic principles observed and reported
o TRL 2: Technology concept and/or application formulated
o TRL 3: Analytical and experimental critical function and/or
characteristic proof-of-concept developed
o TRL 4: Component validation in laboratory environment
o TRL 5: Component and/or validation in relevant environment
o TRL 6: System or subsystem model or prototype demonstrated in a
relevant environment
o TRL 7: System prototype demonstrated in a space environment
Appendix I
Objectives, Scope, and Methodology
o TRL 8: Actual system completed and "flight qualified" through test and
demonstration
o TRL 9: Actual system "flight proven" through successful mission
operations
To determine what factors, if any, slow the implementation of advancements
in cabin occupant safety and health, we reviewed the relevant literature
and interviewed and analyzed documentation from the U.S. federal officials
cited above for the 18 key regulatory actions FAA has taken since 1984 to
improve the safety and health of cabin occupants. We used this same
approach to assess the regulatory status of the 28 advancements we
reviewed that are either currently available, but not yet implemented or
installed, or require further research to demonstrate their effectiveness
or lower their costs. In identifying 28 advancements, GAO is not
suggesting that these are the only advancements being pursued; rather,
these advancements have been recognized by aviation safety experts we
contacted as offering promise for improving the safety and health of cabin
occupants. To determine how long it generally takes for FAA to issue new
rules, in addition to speaking with FAA officials, we relied on past GAO
work and updated it, as necessary. In order to examine the effect of FAA
and European efforts to harmonize their aviation safety requirements, we
interviewed and analyzed documentation from aviation safety officials and
other experts in the United States, Canada, and Europe. Furthermore, to
examine the factors affecting airlines' ability to implement or install
advancements after FAA requires them, we interviewed and analyzed
documentation from aircraft manufacturers, ATA, and FAA officials.
In addition, to determine what factors slow implementation we examined
FAA's processes for selecting research projects to improve cabin occupant
safety and health. In examining whether FAA has sufficient data upon which
to base its research priorities, we interviewed FAA and National
Transportation Safety Board (NTSB) officials about autopsy and survivor
information from commercial airliner accidents. We also examined the use
of cost and effectiveness data in FAA's research selection process for
cabin occupant safety and health projects. To facilitate FAA's development
of such cost estimates, we developed a cost analysis methodology to
illustrate how the agency could do this. Specifically, we developed a cost
analysis for inflatable lap belts to show how data on key cost variables
could be obtained from a variety of sources. We selected lap belts because
they were being used in limited situations and appeared to offer some
measure of improved safety. Information on installation price, annual
maintenance and
Appendix I
Objectives, Scope, and Methodology
refurbishment costs, and added weight of these belts was obtained from
belt manufacturers. We obtained information from FAA and the Department of
Transportation's (DOT) Bureau of Transportation Statistics on a number of
cost variables, including historical jet fuel prices, the impact on jet
fuel consumption of carrying additional weight, the average number of
hours flown per year, the average number of seats per airplane, the number
of airplanes in the U.S. fleet, and the number of passenger tickets issued
per year. To account for variation in the values of these cost variables,
we performed a Monte Carlo simulation.1 In this simulation, values were
randomly drawn 10,000 times from probability distributions characterizing
possible values for the number of seat belts per airplane, seat
installation price, jet fuel price, number of passenger tickets, number of
airplanes, and hours flown. This simulation resulted in forecasts of the
life-cycle cost per airplane, the annualized cost per airplane, and the
cost per ticket. There is uncertainty in estimating the number of lives
potentially saved and their value because accidents occur infrequently and
unpredictably. Such estimates could be higher or lower, depending on the
number and severity of accidents during a given analysis period and the
value placed on a human life.
To identify factors affecting efforts by Canada and Europe to improve
cabin occupant safety and health we interviewed and collected
documentation from aviation safety experts in the United States, Canada,
and Europe.
We provided segments of a draft of this report to selected external
experts to help ensure its accuracy and completeness. These included the
Air Transport Association, National Transportation Safety Board, Boeing,
Airbus, and aviation authorities in the United Kingdom, France, Canada and
the European Union. We incorporated their comments, as appropriate. The
European Union did not provide comments.
We conducted our review from January 2002 through September 2003 in
accordance with generally accepted government auditing standards.
1A Monte Carlo simulation is a widely used computational method for
generating probability distributions of variables that depend on other
variables or parameters represented as probability distributions.
Appendix II
Canada and Europe Cabin Occupant Safety and Health Responsibilities
The United States, Canada, and members of the European Community are
parties to the International Civil Aviation Organization (ICAO),
established under the Chicago Convention of 1944, which sets minimum
standards and recommended practices for civil aviation. In turn,
individual nations implement aviation standards, including those for
aviation safety. While ICAO's standards and practices are intended to keep
aircraft, crews, and passengers safe, some also address environmental
conditions in aircraft cabins that could affect the health of passengers
and crews. For example, ICAO has standards for preventing the spread of
disease and for spraying aircraft cabins with pesticides to remove
disease-carrying insects.
Canada In Canada, FAA's counterpart for aviation regulations and oversight
is Transport Canada Civil Aviation, which sets standards and regulations
for the safe manufacture, operation, and maintenance of aircraft in
Canada. In addition, Transport Canada Civil Aviation administers,
enforces, and promotes the Aviation Occupational Health and Safety Program
to help ensure the safety and health of crewmembers on board aircraft.1
The department also sets the training and licensing standards for aviation
professionals in Canada, including air traffic controllers, pilots, and
aircraft maintenance engineers. Transport Canada Civil Aviation has more
than 800 inspectors working with Canadian airline operators, aircraft
manufacturers, airport operators, and air navigation service providers to
maintain the safety of Canada's aviation system. These inspectors monitor,
inspect, and audit Canadian aviation companies to verify their compliance
with Transport Canada's aviation regulations and standards for pilot
licensing, aircraft certification, and aircraft operation.
To assess and recommend potential changes to Canada's aviation regulations
and standards, the Canadian Aviation Regulation Advisory Council was
established. This Council is a joint initiative between government and the
aviation community. The Council supports regulatory meetings and technical
working groups, which members of the aviation community can attend. A
number of nongovernmental organizations- including airline operators,
aviation labor organizations, manufacturers, industry associations, and
groups representing the public-are members.
1The Headquarters Division of Transport Canada provides guidance and
assistance to Regional Civil Aviation Safety Inspectors - Occupational
Health and Safety who conduct inspections, investigations, and promotional
visits to ensure that airline operators are committed to the safety and
health of their employees.
Appendix II
Canada and Europe Cabin Occupant Safety
and Health Responsibilities
The Transportation Safety Board (TSB) of Canada is similar to NTSB in the
United States. TSB is a federal agency that operates independently of
Transport Canada Civil Aviation. Its mandate is to advance safety in the
areas of marine, pipeline, rail, and aviation transportation by
o conducting independent investigations, including public inquiries when
necessary, into selected transportation occurrences in order to make
findings as to their causes and contributing factors;
o identifying safety deficiencies, as evidenced by transportation
occurrences;
o making recommendations designed to reduce or eliminate any such
deficiencies; and
o reporting publicly on their investigations and findings.
Under its mandate to conduct investigations, TSB conducts
safety-issue-related investigations and studies. It also maintains a
mandatory incident-reporting system for all modes of transportation. TSB
and Transport Canada Civil Aviation use the statistics derived from this
information to track potential safety concerns in Canada's transportation
system.
TSB investigates aircraft accidents that occur in Canada or involve
aircraft built there. Like NTSB, the Transportation Safety Board can
recommend air safety improvements to Transport Canada Civil Aviation.
Europe Europe supplements the ICAO framework with the European Civil
Aviation Conference, an informal forum through which 38 European countries
formulate policy on civil aviation issues, including safety, but do not
explicitly address passenger health issues. In addition, the European
Union issues legislation concerning aviation safety, certification, and
licensing requirements but has not adopted legislation specifically
related to passenger health. One European directive requires that all
member states assess and limit crewmembers' exposure to radiation from
their flight duties and provide them with information on the effects of
such radiation
Appendix II
Canada and Europe Cabin Occupant Safety
and Health Responsibilities
exposure. The European Commission2 is also providing flight crewmembers
and other mobile workers with free health assessments prior to employment,
with follow-up health assessments at regular intervals.
Another European supplement to the ICAO framework is the Joint Aviation
Authorities (JAA), which represents the civil aviation regulatory
authorities of a number of European states3 that have agreed to cooperate
in developing and implementing common safety regulatory standards and
procedures. JAA uses staff of these authorities to carry out its
responsibilities for making, standardizing, and harmonizing aviation
rules, including those for aviation safety, and for consolidating common
standards among member counties. In addition, JAA is to cooperate with
other regional organizations or national European state authorities to
reach at least JAA's safety level and to foster the worldwide
implementation of harmonized safety standards and requirements through the
conclusion of international arrangements.
Membership in JAA is open to members of the European Civil Aviation
Conference, which currently consists of 41 member countries. Currently, 37
countries are members or candidate members of JAA. JAA is funded by
national contributions; income from the sale of publications and training;
and income from other sources, such as user charges and European Union
grants. National contributions are based on indexes related to the size of
each country's aviation industry. The "largest" countries (France,
Germany, and the United Kingdom) each pay around 16 percent and the
smallest around 0.6 percent of the total contribution income. For 2003,
JAA's total budget was about 6.6 million euros.
In early 1998, JAA launched the Safety Strategy Initiative to develop a
focused safety agenda to support the "continuous improvement of its
effective safety system" and further reduce the annual number of accidents
and fatalities regardless of the growth of air traffic. Two approaches are
being used to develop the agenda:
2The European Union, previously known as the European Community, is an
institutional framework for the construction of a united Europe. The
European Commission is a governing body that proposes policies and
legislation.
3JAA currently has 26 full members and 11 candidate members.
Appendix II
Canada and Europe Cabin Occupant Safety
and Health Responsibilities
o The "historic approach" is based on analyses of past accidents and has
led to the identification of seven initial focus areas-controlled flight
into terrain, approach and landing, loss of control, design related,
weather, occupant safety and survivability, and runway safety.
o The "predictive approach" or "future hazards approach" is based on an
identification of changes in the aviation system.
JAA is cooperating in this effort with FAA and other regulatory bodies to
develop a worldwide safety agenda and avoid duplication of effort. FAA has
taken the lead in the historic approach, and JAA has taken the lead in the
future hazards approach.
JAA officials told us that they use a consensus-based process to develop
rules for aviation safety, including cabin occupant safety and
health-related issues. Reaching consensus among member states is time
consuming, but the officials said the time invested was worthwhile.
Besides making aviation-related decisions, JAA identifies and resolves
differences in word meanings and subtleties across languages-an effort
that is critical to reaching consensus. JAA does not have regulatory
rule-making authority. Once the member states are in agreement, each
member state's legislative authority must adopt the new requirements.
Harmonizing new requirements with U.S. and other international aviation
authorities further adds to the time required to implement new
requirements.
According to JAA officials, they use expert judgment to identify and
prioritize research and development efforts for aviation safety, including
airliner cabin occupant safety and health issues, but JAA plans to move
toward a more data-driven approach.4 While JAA has no funding of its own
for research and development, it recommends research priorities to its
member states. However, JAA officials told us that member states' research
and development efforts are often driven by recent airliner accidents in
the member states, rather than by JAA's priorities. The planned shift from
expert judgment to a more data-driven approach will require more
coordination of aviation research and development across Europe. For
example, in January 2001, a stakeholder group formed by the European
Commissioner for Research issued a planning document entitled European
4According to officials from the United Kingdom's Civil Aviation
Authority, a JAA member, a limited benefit analysis has been developed to
provide guidance, but this document has not yet been published.
Appendix II
Canada and Europe Cabin Occupant Safety
and Health Responsibilities
Aeronautics: A Vision for 2020, which, among other things, characterized
European aeronautics as a cross-border industry, whose research strategy
is shaped within national borders, leading to fragmentation rather than
coherence. The document called for better decision-making and more
efficient and effective research by the European Union, its member states,
and aeronautics stakeholders. JAA officials concurred with this
characterization of European aviation research and development.
Changes lie ahead for JAA and aviation safety in Europe. The European
Union recently created a European Aviation Safety Agency, which will
gradually assume responsibility for rule-making, certification, and
standardization of the application of rules by the national aviation
authorities. This organization will eventually absorb all of JAA's
functions and activities. The full transition from JAA to the safety
agency will take several years--per the regulation,5 the European Aviation
Safety Agency must begin operations by September 28, 2003, and transition
to full operations by March 2007.
5On July 15, 2002, the European Parliament and the Council of the European
Union (E.U.) adopted Regulation (EC) No 1592/2002 establishing common
rules for the E.U. in the field of civil aviation and establishing a new
European Aviation Safety Agency.
Appendix III
Summary of Key Actions FAA Has Taken to Improve Airliner Cabin Safety and
Health Since 1984
Key improvement areas Action taken Purpose Status
Impact
Stronger (16g) passenger FAA required that seats for newly developed To
improve the This rule was published on May
seats aircraft be subjected to more rigorous testing crashworthiness of
17, 1988, and became effective than was previously required. The tests
subject airplane seats and June 16, 1988. However, only the seats to the
forward, downward, and other their ability to prevent newest generation of
airplanes is directional movements that can occur in an or reduce the
severity required to have fully tested and accident. Likely injuries under
various of head, back, and certificated 16g seats. FAA conditions are
estimated by using instrumented femur injuries. proposed a retrofit rule
on October crash test dummies. 4, 2002, to phase in 16g seats fleetwide
within 14 years after adoption of the final rule.
Overhead FAA issued an airworthiness To improve the The airworthiness
bins directive requiring directive to
corrective action for crashworthiness of improve bin
overhead bin designs found connectors became
not to meet the existing some bins after effective November
rules. 20, 1992, and
failures were applied to Boeing
737 and 757
observed in a 1989 aircraft.
crash in Kegworth,
England.
Fire
More stringent flammability In 1986, FAA upgraded the fire safety
standards To give airliner cabin FAA required that all commercial
standards for interior for cabin interior materials in transport occupants
more time aircraft produced after August 20, materials airplanes,
establishing a new test method to to evacuate a burning 1988, have panels
that exhibit determine the heat release from materials exposed to radiant
heat and set allowable criteria for heat release rates. airplane by
limiting heat releases and smoke emissions when cabin interior materials
are exposed to fire. reduced heat releases and smoke emissions to delay
the onset of flashover. Although there was no retrofit of the existing
fleet, FAA is requiring that these improved materials be used whenever the
cabin is substantially refurbished.
In 1984, FAA issued a To retard This rule
"Fire-blocking" seat regulation that burning of applies to
enhanced transport
flammability cabin materials category
cushions requirements for seat to aircraft after
cushions. November
increase 26, 1987.
evacuation
time.
Halon fire extinguishers In March 1985, FAA issued a rule requiring at To
extinguish in-flight This rule became effective April least two Halon fire
extinguishers on all fires. 29, 1985, and required commercial airliners,
in addition to other compliance by April 29, 1986. required extinguishers
Smoke detectors in In March 1985, FAA issued a rule requiring air To
identify and This rule became effective on April
lavatories carriers to install smoke detectors in lavatories extinguish
in-flight 29, 1985, and required within 18 months. fires. compliance by
October 29, 1986.
Fire extinguishers built in to In March 1985, FAA required air carriers to
To identify and This rule became effective on April lavatory waste
receptacles install automatic fire extinguishers in the waste extinguish
prevent in-29, 1985. paper bins in all aircraft lavatories. flight fires.
This rule required compliance by April 29, 1987.
Appendix III
Summary of Key Actions FAA Has Taken to
Improve Airliner Cabin Safety and Health
Since 1984
(Continued From Previous Page)
Key improvement areas Action taken Purpose Status
Cargo In 1986, FAA upgraded the To improve fire This rule
compartment airworthiness safety required
compliance on
protection standards for ceiling and in the cargo and March 20, 1998.
sidewall liner panels
used in cargo compartments baggage
of transport
category airplanes. compartment of
certain
transport
aairplanes.
Cargo compartment fire In 1998, FAA required air carriers to retrofit the
To improve fire safety This rule became effective March
detection and suppression U.S. passenger airliner fleet with fire
detection in the cargo and 19, 1998, requiring compliance on and
suppression systems in certain cargo baggage March 20, 2001. compartments.
This rule applied to over 3,400 compartment of airplanes in service and
all newly manufactured certain transport
a
airplanes. airplanes.
Evacuation
Access to exits: Type III
This rule requires improved access to the Type To help ensure that This rule
became effective June 3,
exits III emergency exits (typically smaller, overwing exits) by providing
an unobstructed passageway to the exit. Transport aircraft with 60 or more
passenger seats were required to comply with the new standards passengers
have an unobstructed passageway to exits during an emergency. 1992,
requiring changes to be made by December 3, 1992. Public address system:
This rule requires that the public address To eliminate reliance This rule
became effective
independent power source system be independently powered for at least on
engine or November 27, 1989, for air carrier 10 minutes and that at least
5 minutes of that auxiliary-power-unit and air taxi airplanes time is
during announcements. operation for manufactured on or after
emergency November 27, 1990. announcements.
Exit row This rule requires that To improve This rule became
seating persons seated next to effective April 5,
emergency exits be 1990, requiring
physically and mentally passenger compliance by
capable of operating the evacuation in October 5, 1990.
exit and assisting other an
passengers in emergency emergency.
evacuations.
Location of Rule issued to limit the This rule became
passenger distance between To improve effective July 24,
emergency exits adjacent emergency exits 1989, imposing
on transport passenger requirements on
airplanes to 60 feet. evacuation in airplanes
an manufactured after
emergency. October 16, 1987.
Floor proximity emergency Airplane emergency lighting systems must To
improve This rule became effective escape path marking visually identify
the emergency escape path passenger November 26, 1984, requiring
and identify each exit from the escape path. evacuation when
implementation for large transport smoke obscures airplanes by November
26, 1986. overhead lighting.
Fire-resistant Emergency evacuation slides To improve This technical
evacuation manufactured standard became
slides after December 3, 1984, must effective for all
be fire resistant passenger evacuation slides
and comply with new radiant evacuation. manufactured after
heat testing December 3,
procedures. b 1984.
General safety and health
Preparation for In 1986, FAA issued a To improve air This rule became
in-flight rule requiring effective August
commercial airlines to carriers' 1, 1986,
emergencies carry emergency medical preparation requiring
compliance as
kits. for in-flight of that date.
emergencies.
Appendix III
Summary of Key Actions FAA Has Taken to
Improve Airliner Cabin Safety and Health
Since 1984
(Continued From Previous Page)
Key improvement areas Action taken Purpose Status
Ban on smoking for In 1988 and 1989, the Congress passed To limit the
impact of These laws became effective in majority of domestic legislation
banning smoking on domestic flights poor cabin air quality 1988, and 1990,
respectively. commercial flights of varying durations. on occupants'
health
Prevention of in-flight In June 1995, following two serious events To
prevent passenger Information is currently posted on
injuries involving turbulence, FAA issued a public injuries from FAA's Web
site. advisory to airlines urging the use of seat belts turbulence by at
all times when passengers are seated but increasing public concluded that
existing rules did not require awareness of the strengthening. importance
of
wearing seatbelts. In May 2000, FAA instituted the Turbulence Happens
public awareness campaign.
Source: GAO presentation of FAA information.
aTechnical Class C category cargo compartments are required to have
built-in extinguishing systems to control fire in lieu of crewmember
accessibility. Class D category cargo compartments are required to
completely contain a fire without endangering the safety of the airplane
occupants.
bStandard Order (TSO)-C69B (``Emergency Evacuation Slides, Ramps,
Ramp/Slides, and Slide/Rafts'') prescribes minimum performance standards
for emergency evacuation slides, ramps, ramp/slides, and slide/rafts,
including standards for resistance to radiant heat sources.
Appendix IV
Summaries of Potential Impact Safety Advancements
This appendix presents information on the background and status of
potential advancements in impact safety that we identified, including the
following:
o retrofitting all commercial aircraft with more advanced seats,
o improving the ability of airplane floors to hold seats in an accident,
o preventing overhead luggage bins from becoming detached or opening,
o requiring child safety restraints for children under 40 pounds, and
o installing lap belts with self-contained inflatable air bags.1
Retrofitting All Commercial Aircraft with More Advanced Seats
Background In commercial transport airplanes, the ability of a seat to
protect a passenger from the forces of impact in an accident depends on
reducing the forces of impact to levels that a person can withstand,
either by spreading the impact over a larger part of the person's body or
by decreasing the duration of the impact through the use of
energy-absorbing seats, an energy-absorbing fuselage and floors, or
restraints such as seat belts or inflatable seat belt air bags adapted
from automobile technology. In a 1996 study by R.G.W Cherry & Associates,
enhancing occupant restraint was ranked as the second most important of 33
potential ways to improve air crash survivability.2 Boeing officials noted
that the industry generally
1Officials with the United Kingdom's Civil Aviation Authority commented
that inflatable airbags are but one solution for providing upper torso
restraint. These officials cited a European Union funded "Going Safe"
seat, which through an energy-absorbing device enables a lap and diagonal
belt system to be fitted to an unmodified seat rail.
2R.G.W. Cherry & Associates, Analysis of Structural Factors Influencing
the Survivability of Occupants in Aeroplane Accidents, Civil Aviation
Authority, Paper 96011 (London: December 1996).
Appendix IV
Summaries of Potential Impact Safety
Advancements
agrees with this view but that FAA and the industry are at odds over the
means of implementing these changes.
According to an aviation safety expert, seats and restraints should be
considered as a system that involves
o the seats themselves,
o seat restraints such as seat belts,
o seat connections to the floor,
o the spacing between seats, and
o furnishings in the cabin area that occupants could strike in an
accident.
To protect the occupant, a seat must not only absorb energy well but also
stay attached to the floor of the aircraft. In other words, the "tie-down"
chain must remain intact. Although aircraft seat systems are designed to
withstand about 9 to 16 times the force of gravity, the limits of human
tolerance to impact substantially exceed the aircraft and seat design
limits. A number of seat and restraint devices have been shown in testing
to improve survivability in aviation accidents. Several options are to
retrofit the entire current fleet with fully tested 16g seats, use
rearward-facing seats, require three-point auto-style seat belts with
shoulder harnesses, and install auto-style air bags.
FAA regulations require seats for newly certified airplane designs to pass
more extensive tests than were previously required to protect occupants
from impact forces of up to 16 times the force of normal gravity in the
forward direction; seat certification standards include specific
requirements to protect against head, spine, and leg injuries (see fig.
5).3 FAA first required 16g seats and tests for newly designed,
certificated
3The 1988 seat dynamic performance standards changed seat standards and
testing. The new standards expanded seat testing to include potential
injuries caused by head strikes on the back of seats and on stationary
bulkheads, as well as criteria limiting lumbar and femur loads. These
limits, if exceeded, could cause injuries that could prevent evacuation.
Seats must be tested for forces in several directions to account for
forward, downward, and other directional movements such as may occur in an
accident. Previous FAA regulations required seats to be tested in only one
primary direction at 9gs of force. The 16g level was adopted rather than a
higher standard because the floor tracks of many of the airplanes in use
in 1988 would break away upon an impact of more than 16gs.
Appendix IV
Summaries of Potential Impact Safety
Advancements
airplanes in 1988; new versions of existing designs were not required to
carry 16g seats.4 Since 1988, however, in anticipation of a fleetwide
retrofit rule, manufacturers have increasingly equipped new airplanes with
"16g-compatible" seats that have some of the characteristics of fully
certified 16g seats.5 Certifying a narrow-body airplane type to full 16g
seat certification standards can cost $250,000.6,7
Figure 5: Coach Seating and Impact Position in Coach Seating
4The initial proposed rule, Retrofit of Improved Seats in Air Carrier
Transport-Category Airplanes, 53 Fed. Reg. 17650 (1988) proposed requiring
compliance with improved crashworthiness standards for all seats of
transport-category airplanes used under part 121 and part 135 and
prohibiting the operation of these airplanes unless all seats met the
crashworthiness performance standards required by Improved Seat Safety
Standards, 53 Fed. Reg. 17640 (1988).
5In general, most 16g-compatible seats meet the structural requirements of
the 16g seat rule but do not need to meet the head injury criteria.
6Each aircraft type typically has 8 to 10 different types of seats, each
of which must be certified; a typical economy class seat costs about
$1,800. For marketing reasons, airlines usually choose their own
distinctive seats, which must be certified for each type of airplane they
fly.
7According to a Boeing Official, one cost estimate compiled by ATA and the
Aerospace Industries Association in response to NPRM 88-8 presented in
December 1988 showed the recurring per program cost [was listed] at
$440,000.
Appendix IV
Summaries of Potential Impact Safety
Advancements
In 1998 FAA estimated that 16g seats would avoid between about 210 to 410
fatalities and 220 to 240 serious injuries over the 20-year period from
1999 through 2018. A 2000 study funded by FAA and the British Civil
Aviation Authority estimated that if 16g seats had been installed in all
airplanes that crashed from 1984 through 1998, between 23 to 51 fewer U.S.
fatalities and 18 to 54 fewer U.S. serious injuries would have occurred
over the period. A number of accidents analyzed in that study showed no
benefit from 16g seats because it was assumed that 16g seats would have
detached from the floor, offering no additional benefits compared with
older seats.8 Worldwide, the study estimated, about 333 fewer fatalities
and 354 fewer serious injuries would have occurred during the period had
the improved seats been installed. Moreover, if fire risks had been
reduced, the estimated benefits of 16g seats might have increased
dramatically, as more occupants who were assumed to survive the impact but
die in the ensuing fire would then have survived both the impact and
fire.9
Status Seats that meet the 16g certification requirements are currently
available and have been required on newly certificated aircraft designs
since 1988. However, newly manufactured airplanes of older certification,
such as Boeing 737s, 757s, or 767s, were not required to be equipped with
16g certified seats. Recently, FAA has negotiated with manufacturers to
install full 16g seats on new versions of older designs, such as all newly
produced 737s.10 In October 2002, FAA published a new proposal to create a
timetable for all airplanes to carry fully certified 16g seats within 14
years.11 The comment period for the currently proposed rule ended in March
2003.
8R.G.W. Cherry & Associates, Benefit Analysis for Aircraft 16-g Dynamic
Seats, DOT/FAA/AR-00/13 (Washington, D.C.: April 2000). This study
examined 25 large commercial airplane accidents that occurred from 1984
and through 1998 and possibly involved seat-related fatalities or
injuries.
9In commenting on the proposed 16g seat retrofit rule, Boeing noted that
there were fundamental, fatal flaws in both the analysis of benefits and
the analysis of costs of implementing this rule.
10Until recently, FAA generally did not require a manufacturer to meet
new, higher safety standards that are put in place after the date the
manufacturer applies for a type certificate unless FAA can demonstrate
that an unsafe condition exists. FAA's changed product rule requires
manufacturers to comply with the latest airworthiness standards when
significant design changes are proposed for a derivative aircraft that
will be certificated under an amended or supplemental type certificate. 65
Fed. Reg. 36244 (2002).
11Improved Seats in Air Carrier Transport Category Airplanes, 67 Fed. Reg.
62294 (2002).
Appendix IV
Summaries of Potential Impact Safety
Advancements
Under this proposal, airframe manufacturers would have 4 years to begin
installing 16g seats in newly manufactured aircraft only, and all
airplanes would have to be equipped with full 16g seats within 14 years or
when scheduled for normal seat replacement. FAA estimated that upgrading
passenger and flight attendant seats to meet full 16g requirements would
avert approximately 114 fatalities and 133 serious injuries over 20 years
following the effective date of the rule. This includes 36 deaths that
would be prevented by improvements to flight attendant seats that would
permit attendants to survive the impact and to assist more passengers in
an evacuation.
FAA estimated the costs to avert 114 fatalities and 133 serious injuries
at $245 million in present-value terms, or $519 million in overall costs,
which, according to FAA's analysis, would approximate the monetary
benefits from the seats.12 FAA estimated that about 7.5 percent of
airplane seats would have to be replaced before they would ordinarily be
scheduled for replacement. FAA's October 2002 proposal divides seats into
three classes according to their approximate performance level. Although
FAA does not know how many seats of each type seat are in service, it
estimates that about 44 percent of commercial-service aircraft are
equipped with full 16g seats, 55 percent have 16g-compatible seats, and
about 1 percent have 9g seats. The 16g-compatible or partial 16g seats
span a wide range of capabilities; some are nearly identical to full 16g
seats but have been labeled as 16g-compatible to avoid more costly
certification, and other partial 16g seats offer only minor improvements
over the older generation of 9g seats. To determine whether these seats
have the same performance characteristics as full 16g seats, it may be
sufficient, in some cases, to review the company's certification
paperwork; in other cases, however, full crash testing of actual 16g seats
may be necessary to determine the level of protection provided.
FAA is currently considering the comments it received on its October 2002
proposal. Industry comments raised concerns about general costs, the costs
of retrofitting flight attendant seats, and the possibility that older
airplanes designed for 9g seats might require structural changes to
accommodate full 16g seats. One comment expressed the desire to give some
credit for and "grandfather" in at least some partial 16g seats.
12FAA assumed benefits of $3 million for an averted fatality and $0.5
million for an averted serious injury.
Appendix IV
Summaries of Potential Impact Safety
Advancements
Improving the Ability of Airplane Floors to Hold Seats in an Accident
Background In an accident, a passenger's chances of survival depend on how
well the passenger cabin maintains "living space" and the passenger is
"tied down" within that space. Many experts and reports have noted floor
retention- the ability of the aircraft cabin floor to remain intact and
hold the passenger's seat and restraint system during a crash-as critical
to increasing the passenger's chances of survival. Floor design concepts
developed during the late 1940s and 1950s form the basis for the cabin
floors found in today's modern airplanes.
Accident investigations have documented failures of the floor system in
crashes.13 New 16g seat requirements were developed in the 1980s. 16g
seats were intended to be retrofitted on aircraft with traditional 9g
floors and were designed to maximize the capabilities of existing floor
strength. While 16g seats might be strong, they could also be inflexible
and thus fail if the floor deformed in a crash. Under the current 16g
requirement, the seats must remain attached to a deformed seat track and
floor structure representative of that used in the airplane.14 To meet
these requirements, the seat was expected to permanently deform to absorb
and limit impact forces even if the 16g test conditions were exceeded
during a crash.
A major accident related to floor deformation occurred at Kegworth,
England, in 1989. A Boeing 737-400 airplane flew into an embankment on
approach to landing. In total, only 21 of the 52 triple seats-all
"16g-compatible" -remained fully attached to the cabin floor; 14 of those
that remained attached were in the area where the wing passes through the
13A study of survivable accidents that took place from 1970 through 1978
indicated that floor deformation during a crash was a primary cause of
seat failure in 60 percent of the accidents. (Chandler, et al.,
DOT/FAA/CT-82-118)
14In the dynamic 16g seat test with a deformed floor, one floor track must
be pitched 10 degrees (up or down) relative to the other floor track,
which must in turn be rolled 10 degrees.
Appendix IV
Summaries of Potential Impact Safety
Advancements
cabin and the area is stronger than other areas to support the wing.15 In
this section of the airplane, the occupants generally survived, even
though they were exposed to an estimated peak level of 26gs. The front
part of the airplane was destroyed, including the floor; most of these
seats separated from the airplane, killing or seriously injuring the
occupants. An FAA expert noted that the impact was too severe for the
airplane to maintain its structural integrity and that 16g seats were not
designed for an accident of that severity. The British Air Accidents
Investigation Branch noted that fewer injuries occurred in the accident
than would probably have been the case with earlier-generation seats.
However, the Branch also noted that "relatively minor engineering changes
could significantly improve the resilience and toughness of cabin floors .
. . and take fuller advantage of the improved passenger seats." The Branch
reported that where failures occurred, it was generally the seat track
along the floor that failed, and not the seat, and that the rear
attachments generally remained engaged with the floor, "at least partially
due to the articulated joint built into the rear attachment, an innovation
largely stemming from the FAA dynamic test requirements." The Branch
concluded that "seats designed to these dynamic requirements will
certainly increase survivability" but "do not necessarily represent an
optimum for the long term . . . if matched with cabin floors of improved
strength and toughness."16
Status Several reports have recommended structural improvements to floors.
A case study of 11 major accidents for which detailed information was
available found floor issues to be a major cause of injury or fatalities
in 4 accidents and a minor cause in 1 accident. Another study estimated
the past benefits of 16g seats in U.S. accidents between 1984 and 1998 and
found no hypothetical benefit from 16g seats in a number of accidents
because the floor was extensively disrupted during impact.17 In other
15Some 16g-compatible seats were manufactured to meet 16g dynamic testing
standards but did not complete FAA's certification process for floor
deformation on representative floors and seat tracks and technically met
only the 9g seat certification requirements.
16Report on the accident to Boeing 737-400 G-OBME near Kegworth,
Leicestershire, on 8 January 1989, Aircraft Accident Report 4/90, AAIB,
DOT, London, HMSO; "Recommendations for Injury Prevention in Transport
Aviation Accidents," prepared for NASA, Langley Research Center, by Simula
Technologies, Inc., February 2, 2000, TR-99112, S97324.
17 "Benefit Analysis for Aircraft 16-g Dynamic Seats," Final Report, U.S.
Department of Transportation (DOT/FAA/AR-00/13) and U.K Civil Aviation
Authority (CAA Paper 99003).
Appendix IV
Summaries of Potential Impact Safety
Advancements
words, unless the accidents had been less severe or the floor and seat
tracks had been improved beyond the 9g standard on both new and old jets,
newer 16g seats would not have offered additional benefits compared with
the older seats that were actually on the airplane during the accidents
under study.
A research program on seat and floor strength was recently conducted by
the French civil aviation authority, the Direction Generale de l'Aviation
Civile. Initial findings of the research program on seat-floor attachments
have not shown dramatic results and showed no rupture or plastic
deformation of any cabin floor parts during a 16g test. However, French
officials noted that they plan to perform additional tests with more rigid
seats. Because many factors are involved it is difficult to identify the
interrelated issues and interactions between seats and floors. A possible
area for future research, according to French officials, is to examine
dynamic floor warping during a crash to improve impact performance.
FAA officials said they have no plans to change floor strength
requirements. FAA regulations require floors to meet impact forces likely
to occur in "emergency landing conditions," or generally about 9gs of
longitudinal static force. According to several experts, stronger floors
could improve the performance of 16g seats. In addition, further
improvement in seats beyond the 16g standard would likely require improved
floors.
Preventing Overhead Storage Bin Detachment to Protect Passengers in an
Accident
Background In an airplane crash, overhead luggage bins in the cabin
sometimes detach from their mountings along the ceiling and sidewalls and
can fall completely or allow pieces of luggage to fall on passengers'
heads (See fig. 6.). While only a few cases have been reported in which
the impact from dislodged overhead bins was the direct cause of a crash
fatality or injury, a study for the British Civil Aviation Authority that
attempted to identify the
Appendix IV
Summaries of Potential Impact Safety
Advancements
specific characteristics of each fatality in 42 fatal accidents estimated
that the integrity of overhead bin stowage was the 17th most important of
32 factors used to predict passenger survivability.18 Maintaining the
integrity of bins may also help speed evacuation after a crash.
Safer bins have been designed since bin problems were observed in a Boeing
737 accident in Kegworth, England, in 1989, when nearly all the bins
failed and fell on passengers. FAA tested bins in response to that
accident. The Kegworth bins were certified to the current FAA 9g
longitudinal static loading standards, among others. When FAA subsequently
conducted longitudinal dynamic loading tests on the types of Boeing bins
involved, the bins failed. Several FAA experts said that the overhead bins
on 737s had a design flaw. FAA then issued an airworthiness directive that
called for modifying all bins on Boeing 737 and 757 aircraft. The
connectors for the bins were strengthened in accordance with the
airworthiness directive, and the new bins passed FAA's tests.
The British Air Accidents Investigation Branch recommended in 1990 that
the performance of both bins and latches be tested more rigorously,
including the performance of bins "when subjected to dynamic crash pulses
substantially beyond the static load factors currently required." NTSB has
made similar recommendations.
Turbulence reportedly injures at least 15 U.S. cabin occupants a year, and
possibly over 100. Most of these injuries are to flight attendants who are
unrestrained. Some injuries are caused by luggage falling from bins that
open in severe turbulence. Estimates of total U.S. airline injuries from
bin-related falling luggage range from 1,200 to 4,500 annually, most of
which occur during cruising rather than during boarding or disembarking.19
The study for the British Civil Aviation Authority noted above found that
as many as 70 percent of impact-related accidents involve overhead bins
that become detached. However, according to the report, bin detachment
does not appear to be a major factor in occupants' survival and data are
insufficient to support a specific determination about the mechanism of
18R.G.W. Cherry & Associates, Analysis of Structural Factors Influencing
the Survivability of Occupants in Aeroplane Accidents, Civil Aviation
Authority, Paper 96011 (London: December 1996).
19Flight Safety Foundation, "Increased Amount and Types of Carry-On
Baggage Bring New Industry Responses," November-December 1997, Vol. 32,
No. 6, p. 6.
Appendix IV
Summaries of Potential Impact Safety
Advancements
failure. FAA has conducted several longitudinal and drop tests since the
Kegworth accident, including drops of airplane fuselage sections with
overhead storage bins installed. A 1993 dynamic vertical drop test showed
some varying bin performance problems at about 36gs of downward force. An
FAA longitudinal test in 1999 tested two types of bins at 6g, at the 9g
FAA certification requirement, and at the 16g level; in the 16g
longitudinal test, one of the two bins broke free from its support
mountings.
Status In addition to the requirement that they withstand forward
(longitudinal) loads of slightly more than 9gs, luggage bins must meet
other directional loading requirements.20 Bin standards are part of the
general certification requirements for all onboard objects of mass. FAA
officials said that overhead bins no longer present a problem, appear to
function as designed, and meet standards. An FAA official told us that
problems such as those identified at Kegworth have not appeared in later
crashes. Another FAA official said that while Boeing has had some record
of bin problems, the problems are occasional and quickly rectified through
design changes. Boeing officials told us that the evidence that bins
currently have latch problems is anecdotal.
Suggestions for making bins safer in an accident include adding features
to absorb impact forces and keep bins attached and closed during
structural deformation; using dynamic 16g longitudinal impact testing
standards similar to those for seats; and storing baggage in alternative
compartments in the main cabin, elsewhere in the aircraft, or under seats
raised for that purpose.
Child Safety Seats
Background Using a correctly-designed child safety seat that is strapped
in an airplane seat offers protection to a child in an accident or
turbulence (see fig. 6). By contrast, according to many experts, holding a
child under two years old on an adult's lap, which is permitted, is unsafe
for both the child and for other
20Bins are required to withstand 9g forward (longitudinal), 3g upward, 6g
downward, and other load requirements.
Appendix IV
Summaries of Potential Impact Safety
Advancements
occupants who could be struck by the child in an accident. Requiring child
safety seats for infants and small children on airplanes is one of NTSB's
"most wanted" transportation safety improvements. The British Air
Accidents Investigation Branch made similar recommendations, as did a 1997
White House Commission report on aviation.
Figure 6: Examples of Child Safety Seats
Appendix IV
Summaries of Potential Impact Safety
Advancements
An FAA analysis of survivable accidents from 1978 through 1994 found that
9 deaths, 4 major injuries, and 8 minor injuries to children occurred. The
analysis also found that the use of child safety seats would have
prevented 5 deaths, all the major injuries, and 4 to 6 of the minor
injuries. Child safety advocates have pointed to several survivable
accidents in which children died-a 1994 Charlotte, North Carolina, crash;
a 1990 Cove Neck, New York, accident; and a 1987 Denver, Colorado,
accident-as evidence of the need for regulation.
A 1992 FAA rule required airlines to allow child restraint systems, but
FAA has opposed mandatory child safety seats on the basis of studies
showing that requiring adults to pay for children's seats would induce
more car travel, which the study said was more dangerous for children than
airplane travel. One study published in 1995 by DOT estimated that if
families were charged full fares for children's seats, 20 percent would
choose other modes of transportation, resulting in a net increase of 82
deaths among children and adults over 10 years.
If child safety seats are required, airlines may require adults wishing to
use child safety seats to purchase an extra seat for the child's safety
seat. FAA officials told us that they could not require that the seat next
to a parent be kept open for a nonpaying child. However, NTSB has
testified that the scenarios for passengers taking other modes of
transportation are flawed because FAA assumed that airlines would charge
full fares for infants currently traveling free. NTSB noted in 1996 that
airlines would offer various discounts and free seats for infants in order
to retain $6 billion in revenue that would otherwise be lost to auto
travel. Airlines have already responded to parents who choose to use child
restraint systems with scheduling flexibility, and many major airlines
offer a 50 percent discount off any fare for a child under 2 to travel in
an approved child safety seat. The 1995 DOT study, however, estimated that
even if a child's seat on an airplane were discounted 75 percent, some
families would still choose car travel and that the choice by those
families to drive instead of fly would result in a net increase of 17
child and adult deaths over 10 years.
In FAA tests, some but not all commercially available automobile child
restraint systems have provided adequate protection in tests simulating
airplane accidents. Prices range from less than $100 for a child safety
seat marketed for use in both automobiles and airplanes to as much as
$1,300 for a child safety seat developed specifically for use in
airplanes.
Appendix IV
Summaries of Potential Impact Safety
Advancements
A drawback to having parents, rather than airlines, provide child safety
seats for air travel is that some models may be more difficult to fit into
airplane seat belts, making a proper fit more challenging. While the
performance of standardized airline-provided seats may be better than that
of varied FAA-certified auto-airplane seats, one airline said that
providing seats could present logistical problems for them. However,
Virgin Atlantic Airlines supplies its own specially developed seats and
prohibits parents from using their own child seats. Because turbulence can
be a more frequent danger to unrestrained children than accidents, one
expert told us that a compromise solution might include allowing some type
of alternative in-flight restraint.
Status Child safety seats are currently available for use on aircraft. The
technical issues involved in designing and manufacturing safe seats for
children to use in both cars and airplanes have largely been solved,
according to FAA policy officials and FAA researchers. Federal regulations
establish requirements for child safety seats designed for use in both
highway vehicles and aircraft by children weighing up to 50 pounds. FAA
officials explained that regulations requiring child safety seats have
been delayed, in part, because of public policy concerns that parents
would drive rather than fly if they were required to buy seats for their
children. On February 18, 1998, FAA asked for comments on an advanced
notice of proposed rule-making to require the use of child safety seats
for children under the age of
2. FAA sponsored a conference in December 1999 to examine child restraint
systems. At that conference, the FAA Administrator said the agency would
mandate child safety seats in aircraft and provide children with the same
level of safety as adults. FAA officials told us that they are still
considering requiring the use of child safety seats but have not made a
final decision to do so. If FAA does decide to provide "one level of
safety" for adults and children, as NTSB advocates, parents may opt to
drive to their destinations to avoid higher travel costs, thereby
statistically exposing themselves and their children to more danger. In
addition, FAA will have to decide whether the parents or airlines will
provide the seats.
If FAA decides to require child safety seats, it will need to harmonize
its requirements with those of other countries where requirements differ,
as the regulations on child restraint systems vary. In Canada, as in the
United States, child safety seats are not mandatory on registered
aircraft. In Europe, the regulations vary from country to country, but no
country requires their use. Australia's policy permits belly belts but
discourages their use. An Australian official said in 1999 that Australia
was waiting for
Appendix IV
Summaries of Potential Impact Safety
Advancements
the United States to develop a policy in this area and would probably
follow that policy.
Inflatable Lap Belt Air Bags
Background Lap belts with inflatable air bags are designed to reduce the
injuries or death that may result when a passenger's head strikes the
airplane interior. These inflatable seat belts adapt advanced automobile
air bag technology to airplane seats in the form of seat belts with
embedded air bags. If a passenger loses consciousness because of a head
injury in an accident, even a minor, nonfatal concussion can cause death
if the airplane is burning and the passenger cannot evacuate quickly.
Slowing the duration of the impact with an air bag lessens its lethality.
According to a manufacturer's tests using airplane seats on crash sleds,
lap belts with air bags can likely reduce some impact injuries to
survivable levels.21
FAA does not require seats to be tested in sled tests for head impact
protection when there would be "no impact" with another seat row or
bulkhead wall, such as when spacing is increased to 42 inches from the
more typical 35 inches. While more closely spaced economy class seat rows
can provide head impact protection through energy-absorbing seat backs,
seats in no impact positions have tested poorly in head injury
experiments, resulting in severe head strikes against the occupants' legs
or the floor, according to the manufacturer. This no impact exemption from
FAA's head injury criteria can include exit rows, business class seats,
and seats behind bulkhead walls and could permit as many as 30 percent of
seats in some airplanes to be exempt from the head impact safety criteria
that row-to-row seats must meet.
Status According to the manufacturer, 13 airlines have installed about
1,000 of the devices in commercial airliners, mainly at bulkhead seats;
about 200 of
21One manufacturer's testing shows that the inflatable lap belts can
reduce head injury criteria scores from about 2,000 to 200-300 in a 16g
impact. A score of 1,000 implies a skull fracture, possible loss of
consciousness, and a 16 percent risk of life-threatening brain injury.
Appendix IV
Summaries of Potential Impact Safety
Advancements
these are installed in the U.S. fleet. All of the orders and installations
so far have been done to meet FAA's seat safety regulations rather than
for marketing reasons, according to the manufacturer.
The airlines would appear to benefit from using the devices in bulkhead
seats if that would allow them to install additional rows of seats. While
the amount of additional revenue would depend on the airplane design and
class of seating, two additional seats may produce more net revenue per
year than the cost for the devices to be installed throughout an
aircraft.22 Economic constraints are acquisition costs, maintenance costs,
and increased fuel costs due to weight. The units currently weigh about 3
pounds per seat, or 2 pounds more than current seat belts. According to
the manufacturer, the air bag lap belts currently cost $950 to $1,100,
including maintenance. The manufacturer estimated that if 5 percent of all
U.S. seat positions were equipped with the devices (about 50,000 seats per
year), the cost would drop to about $300 to $600 per seat, including
installation.23
Lap belt air bags have been commercially available for only a few years.
FAA's Civil Aerospace Medical Institute assisted the developers of the
devices; manufacturers for both passenger and military use (primarily
helicopter) are conducting ongoing research. FAA and other regulatory
bodies have no plans to require their installation, but airlines are
allowed to use them. The extent to which these devices are installed will
depend on each airline's analysis of the cost and benefits.
22At an annual life-cycle cost of approximately $12,000 to outfit an
average airliner with lap belt air bags on all seats of the U.S. fleet,
assuming an installation cost of $450 per seat position not including
maintenance and replacement costs. A GAO analysis of the 2002 Annual
Report of Southwest Airlines, which has relatively low passenger revenue
per available seat mile compared with other airlines, found that each seat
produced an annual net revenue of about $10,000. See appendix VIII for our
analysis of the costs associated with lap belts.
23According to the manufacturer, the installation of the most common
design requires maintenance of one minute per seat position for a
diagnostic test every 1,900 flight hours, and the devices must be
refurbished about once every 7 years at about a third of the initial
price.
Appendix V
Summaries of Potential Fire Safety Advancements
This appendix presents information on the background and status of
potential advancements in fire safety that we identified, including the
following:
o preventing fuel tank explosions with fuel tank inerting;
o preventing in-flight fires with arc fault circuit breakers;
o identifying in-flight fires with multisensor fire and smoke detectors;
o suppressing in-flight and postcrash fires by using water mist fire
suppression systems;
o mitigating postcrash damage and injury by using less flammable fuels;
o mitigating in-flight and postcrash fires by using fire-resistant
thermal acoustic insulation;
o mitigating fire-related deaths and injuries by using
ultra-fire-resistant polymers; and
o mitigating fire deaths and injuries with sufficient airport rescue and
fire fighting.
Fuel Tank Inerting
Background Fuel tank inerting involves pumping nitrogen-enriched air into
an airliner's fuel tanks to reduce the concentration of oxygen to a level
that will not support combustion. Nitrogen gas makes a fuel tank safer by
serving as a fire suppressant. The process can be performed with both
ground-based and onboard systems, and it significantly reduces the
flammability of the center wing tanks, thereby lowering the likelihood of
a fuel tank explosion.
Following the crash of TWA Flight 800 in 1996, in which 230 people died,
NTSB determined that the probable cause of the accident was an explosion
in the center wing fuel tank. The explosion resulted from the ignition of
flammable fuel vapors in this tank, which is located in the fuselage in
the space between the wing junctions. NTSB subsequently placed the
improvement of fuel tank design on its list of "Most Wanted Safety
Appendix V
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Improvements" and recommended that fuel tank inerting be considered an
option to eliminate the likelihood of fuel tank explosions.
FAA issued Special Federal Aviation Regulation 881 to eliminate or
minimize the likelihood of ignition sources by revisiting the fuel tank's
design. Issued in 2001, the regulation consists of a series of FAA
regulatory actions aimed at preventing the failure of fuel pumps and pump
motors, fuel gauges, and electrical power wires inside these fuel tanks.
In late 2002, FAA amended the regulation to allow for an "equivalent level
of safety" and the use of inerting as part of an alternate means of
compliance.
In a 2001 report, an Aviation Rule-making Advisory Committee tasked with
evaluating the benefits of inerting the center wing fuel tank estimated
these benefits in terms of lives saved. After projecting possible
in-flight and ground fuel tank explosions and postcrash fires from 2005
through 2020, the committee estimated that 132 lives might be saved from a
ground-based system and 253 lives might be saved from an onboard system.2
Status Neither of the two major types of fuel tank inerting-ground-based
and onboard-is currently available for use on commercial airliners because
additional development is needed.3 Both types offer benefits and
drawbacks.
o A ground-based system sends a small amount of nitrogen into the center
wing tank before departure. Its benefits include that (1) it requires no
new technology development for installation, (2) the tank can be inerted
in 20 minutes, and (3) it carries a lesser weight penalty. Its drawbacks
include that it is unable to inert for descent, landing, and taxiing to
the
1ATA noted that more than 80 fuel tank Airworthiness Directives have been
adopted since the crash of TWA Flight 800 and that a similar number of
directives are currently under development.
2The committee also estimated, on the basis of data on nitrogen exposure
from the Occupational Safety and Health Administration and the National
Institute of Occupational Safety and Health, that from 24 to 81 lives
could be lost over the same period, depending on the degree of oxygen
depletion. The report did not specifically indicate whether this forecast
was for a ground-based, onboard, hybrid, or any other inerting system.
3By using more general terminology, this terminology excludes hybrid and
liquid nitrogen inerting systems, also considered by the Aviation
Rule-making Advisory Committees for their 1998 and 2001 reports.
Appendix V
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destination gate, and nitrogen supply systems are needed at each terminal
gate and remote parking area at every airport.
o An onboard system generates nitrogen by transferring some of the engine
bleed air - air extracted from the jet engines to supply the cabin
pressurization system in normal flight-through a module that separates air
into oxygen and nitrogen and discharges the nitrogen enriched air into the
fuel tank. Its benefits include that (1) it is self-reliant and (2) it
significantly reduces an airplane's vulnerability to lightning, static
electricity, and incendiary projectiles throughout the flight's duration.4
Its drawbacks include that it (1) weighs more, (2) increases the
aircraft's operating costs, and (3) may decrease the aircraft's
reliability.5
According to FAA, its fire safety experts' efforts to develop a
lighter-weight system for center wing tank inerting have significantly
increased the industry's involvement. Boeing and Airbus are working on
programs to test inerting systems in flight. For example, Boeing has
recently completed a flight test program with a prototype system on a 747.
None of the U.S. commercial fleet is equipped with either ground-based or
onboard inerting systems, though onboard systems are in use in U.S. and
European military aircraft. Companies working in this field are focused on
developing new inerting technologies or modifying existing ones. A
European consortium is developing a system that combines onboard center
wing fuel tank inerting with sensors and a water-mist-plus-nitrogen fire
suppression system for commercial airplanes.
In late 2002, FAA researchers successfully ground-tested a prototype
onboard inerting system using current technology on a Boeing 747SP. New
research also enabled the agency to ease a design requirement, making the
inerting technology more cost-effective. This new research showed that
4According to an FAA safety expert, FAA is addressing only the center wing
tank because of its significantly higher flammability exposure and the low
risk of an explosion in the wing tanks.
5A current controversial issue is whether inerting technology will be
considered flight-critical hardware-and therefore will be required to
function properly for the aircraft to fly. If it is deemed flight
critical, its reliability may affect the dispatch rate of the aircraft.
For example, if the technology experiences operational problems, the
aircraft may be allowed to fly only 25 times a week, even if it is
scheduled to fly 30 times a week. This problem reduces revenue to the
airline and is a greater concern for civilian than for military aviation,
because there are usually replacements for military aircraft.
Appendix V
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reducing the oxygen level in the fuel tank to 12 percent-rather than 9
percent, as was previously thought-is sufficient to prevent fuel tank
explosions in civilian aircraft.6 FAA also developed a system that did not
need the compressors that some had considered necessary. Together, these
findings allowed for reductions in the size and power demands of the
system.
FAA plans to focus further development on the more practical and
cost-effective onboard fuel tank inerting systems. For example, to further
improve their cost-effectiveness, the systems could be designed both to
suppress in-flight cargo fires, thereby allowing them to replace Halon
extinguishing agents, and to generate oxygen for emergency
depressurizations, thereby allowing them to replace stored oxygen or
chemical oxygen generators.
NASA is also conducting longer-term research on advanced technology
onboard inert gas-generating systems and onboard oxygen-generating
systems. Its research is intended (1) to develop the technology to improve
its efficiency, weight, and reliability and (2) to make the technology
practical for commercial air transport. NASA will fund the development of
emerging technologies for ground-based technology demonstration in fiscal
year 2004. NASA is also considering the extension of civilian transport
inerting technology to all fuel tanks to help protect airplanes against
terrorist acts during approaches and departures.
The cost of the system, its corresponding weight, and its unknown
reliability are the most significant factors affecting the potential use
of center wing fuel tank inerting. New cost and weight estimates are
anticipated in 2003.
6FAA fuel tank safety experts conducted tests under high temperatures and
found that a tank with an oxygen level of 12 percent was inert against
internal threats, such as sparks and hot surfaces. According to one FAA
expert, the system provides a "below 12 percent" inert tank under all
conditions except for a brief time during descent when local pockets in
the tank may approach 16 percent oxygen. The expert said that at this
time, the tank is generally cool enough to be nonflammable even with
normal air (21 percent oxygen) in the tank. If the tank is cool enough,
internal threats will not ignite the fuel air mixture. He said the
probability of explosions is very low in the wing tanks because they are
not heated by other airplane systems.
Appendix V
Summaries of Potential Fire Safety
Advancements
o In 2001, FAA estimated total costs to equip the worldwide fleet at $9.9
billion for ground-based, and $20.8 billion for onboard, inerting
systems.7
o In 2002, FAA officials developed an onboard system for B-747
flight-testing. The estimated cost was $460,000. The officials estimated
that each system after that would cost about $200,000. The weight of the
FAA prototype system is 160 pounds.8 A year earlier, NASA estimated the
weight for a B-777 system with technology in use in military aircraft at
about 550 pounds.9
Arc Fault Circuit Breaker
Background Arcing faults in wiring may provide an ignition source that can
start fires. Electrical wiring that is sufficiently damaged might cause
arcing or direct shorting resulting in smoking, overheating, or ignition
of neighboring materials. A review of data produced by FAA, the Airline
Pilots Association, and Boeing showed that electrical systems have been a
factor in approximately 50 percent of all aircraft occurrences involving
smoke or fire and that wiring has been implicated in about 10 percent of
those occurrences. In addition, faulty or malfunctioning wiring has been a
factor in at least 15 accidents or incidents investigated by NTSB since
1983. Properly selecting, routing, clamping, tying, replacing, marking,
separating, and cleaning around wiring areas and proper maintenance all
help mitigate the potential for wire system failures, such as arcing, that
could lead to smoke, fire and loss of function. Chemical degradation, age
induced cracking, and damage due to maintenance may all create a scenario
which
7These estimates included the costs for modifying aircraft that are
currently in service, in production, and being designed, and they assumed
a predicted reduction in the accident rate of 75 percent.
8This system does not have the capability to inert the cargo compartment,
bay, and wheel well, and it dumps oxygen as effluent rather than using it
for an emergency passenger oxygen system.
9A 2001 NASA study indicated that two liquid nitrogen systems were the
only ones that appeared capable of inerting all fuel tanks of a commercial
aircraft full time.
Appendix V
Summaries of Potential Fire Safety
Advancements
could lead to arcing. Arcing can occur between a wire and structure or
between different wire types. Wire chafing is a sign of degradation;
chafing happens when the insulation around one wire rubs against a
component tougher than itself (such as structure or control cable)
exposing the wire conductor. This condition can lead to arcing. When
arcing wires are too close to flammable materials or are flammable
themselves, fires can occur.
In general, wiring and wiring insulation degrade for a variety of reasons,
including age, inadequate maintenance, chemical contamination, improper
installation or repair, and mechanical damage. Vibration, moisture, and
heat can contribute to and accelerate degradation. Consequences of wire
systems failures include loss of function, smoke, and fire. Since most
wiring is bundled and located in hidden or inaccessible areas, it is
difficult to monitor the health of an aircraft's wiring system during
scheduled maintenance using existing equipment and procedures. Failure
occurrences have been documented in wiring running to the fuel tank, in
the electronics equipment compartment, in the cockpit, in the ceiling of
the cabin, and in other locations.
To address the concerns with arcing, arc fault circuit breakers for
aircraft use are being developed. The arc fault circuit breaker cuts power
off as it senses a wire beginning to arc. It is intended to prevent
significant damage before a failure develops into a full-blown arc, which
can produce extremely localized heat, char insulation, and generally
create problems in the wire bundles. Arc fault circuit protection devices
would mitigate arcing events, but will not identify the wire breaches and
degradation that typically lead up to these events.
Status FAA, the Navy, and the Air Force are jointly developing arc fault
circuit breaker technology. Boeing is also developing a monitoring system
to detect the status of and changes in wiring; and power shuts down when
arcing is detected. This system may be able to protect wiring against both
electrical overheating and arcing and is considered more advanced than the
government's circuit breaker technology.
FAA developed a plan called the Enhanced Airworthiness Program for
Airplane Systems to address wiring problems, which includes development of
arc fault circuit breaker technology and installation guidance along with
proposals of new regulations. The plan provides means for enhancing safety
in the areas of wire system design, certification, maintenance, research
and development, reporting, and information sharing and
Appendix V
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outreach. FAA also tasked an Aging Transport Systems Rule-making Advisory
Committee to provide data, recommendations, and evaluation specifically on
aging wiring systems. The new regulations being considered are entitled
the Enhanced Airworthiness Program for Airplane Systems Rule and are
expected by late-2005. Under this rule-making package, inspections would
evaluate the health of wiring and all of its components for operation,
such as connectors and clamps. Part of the system includes visual
inspections of all wiring within arm's reach, enhanced by the use of
hand-held mirrors. This improvement is expected to catch more wiring flaws
than current visual inspection practices. Where visual inspections can not
be assumed to detect damage, detailed inspections will be required. The
logic process to establish proper inspections is called the Enhanced Zonal
Analysis Procedure, which will be issued as an Advisory Circular. This
procedure is specifically directed towards enhancing the maintenance
programs for aircraft whose current program does not include tasks derived
from a process that specifically considers wiring in all zones as the
potential source of ignition of a fire.
Additional development and testing will be required before advanced arc
fault circuit breakers will be available for use on aircraft. The FAA
currently is in the midst of a prototype program where arc fault circuit
breakers are installed in an anticollision light system on a major air
carrier's Boeing 737. The FAA and the Navy are currently analyzing tests
of the circuit breakers to assess their reliability. The Society of
Automotive Engineers is in the final stages of developing a Minimum
Operating Performance Specification for the arc fault circuit breaker.
Multisensor Detectors
Background Multisensor detectors, or "electronic noses," could combine one
or more standard smoke detector technologies; a variety of sensors for
detecting such gases as carbon monoxide, carbon dioxide, or hydrocarbon;
and a thermal sensor to more accurately detect and locate overheated or
burning materials. The sensors could improve existing fire detection by
discovering and locating potential or actual fires sooner and reducing the
incidence of false alarms. These "smart" sensors would ignore the
"nuisance sources"
Appendix V
Summaries of Potential Fire Safety
Advancements
such as dirt, dust, and condensation that are often responsible for
triggering false alarms in existing systems.10
According to studies by FAA and the National Institute of Standards and
Technology, many current smoke and fire detection systems are not
reliable. A 2000 FAA study indicated that cargo compartment detection
systems, for example, resulted in at least one false alarm per week from
1988 through 1990 and a 200:1 ratio of false alarms to actual fires in the
cargo compartment from 1995 through 1999. 11 FAA has since estimated a
100:1 cargo compartment false alarm ratio, partly because reported actual
incidents have increased According to FAA's Service Difficulty Report
database,12 about 990 actual smoke and fire events were reported for
2001.13
Multisensor detectors could be wired or wireless and linked to a
suppression system. One or several sensor signals or indicators could
cause the crew to activate fire extinguishers in a small area or zone, a
larger area, or an entire compartment, resulting in a more appropriate and
accurate use of the fire suppressant. For example, in areas such as the
avionics compartment, materials that can burn are relatively well-defined.
Multisensor detectors the size of a postage stamp could be designed to
detect smoldering fires in cables or insulation or in overheated equipment
in that area. Placing the detectors elsewhere in the airplane could
improve the crew's ability to respond to smoke or fire, including
occurrences in hidden or inaccessible areas.
Improved sensor detection technologies would both enhance safety by
increasing crews' confidence in the reliability of alarms and reduce costs
by avoiding the need to divert aircraft in response to false alarms. One
10One type of smart sensor would analyze the light-scattering properties
of the particles in the air to differentiate between smoke particles and
nuisance sources.
11Aircraft Cargo Compartment Smoke Detector Alarm Incidents on
U.S.-Registered Aircraft, 1974-1999, DOT/FAA/AR-TN00/29 (Washington, D.C.:
June 2000). The study indicated a generally increasing number of false
alarms as the size of the fleet grew.
12Operating requirements for all aircraft have been amended by a 2000
final rule, whose deadline was recently extended for the third time, to
report the occurrence or detection of failures, malfunctions, or defects
concerning fire warning systems and false warnings of fire or smoke in the
entire U.S. fleet.
13According to FAA fire safety experts, most of these are contaminated air
or smoke events in the cabin, detected by people, not by detectors.
Appendix V
Summaries of Potential Fire Safety
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study estimated the average cost of a diversion at $50,000 for a wide-body
airplane and $30,000 for a narrow-body airplane. A diversion can also
present safety concerns because of the possible increased risk of an
accident and injuries to passengers and crew if there is (1) an emergency
evacuation, (2) a landing at an unfamiliar airport, (3) a change to air
traffic patterns, (4) a shorter runway, (5) inferior fire-fighting
capability, (6) a loss of cargo load, or (7) inferior navigation aids. In
2002, 258 unscheduled landings due to smoke, fire, or fumes occurred. In
addition, 342 flights were interrupted; some of these flights had to
return to the gate or abort a takeoff.
FAA established basic detector performance requirements in 1965 and 1980.
Detectors were to be made and installed in a manner that ensured their
ability to resist, without failure, all vibration, inertia, and other
loads to which they might normally be subjected; they also had to be
unaffected by exposure to fumes, oil, water, or other fluids. Regulations
in 1986 and 1998 further defined basic location and performance
requirements for detectors in different areas of the cargo compartment. In
1998, FAA issued a requirement for detection and extinguishment systems
for one class of cargo compartments, which relied on oxygen starvation to
control fires. This requirement significantly increased the number of
detectors in use.
Status Multisenor detectors are not currently available because additional
research is needed. Although they have been demonstrated in the laboratory
and on the ground, they have not been flight-tested. FAA and NASA have
multisensor detector research and development efforts under way and are
working to develop "smart" sensors and criteria for their approval. FAA
will also finish revising an Advisory Circular that establishes test
criteria for detection systems, designed to ensure that they respond to
fires, but not to nonfire sources. In addition, several companies
currently market "smart" detectors, mostly for nonaviation applications.
For example, thermal detection systems sense and count certain particles
that initially boil off the surface of smoldering or burning material.
A European consortium has been developing a system, FIREDETEX, that
combines the use of multisensor detectors, onboard fuel tank inerting, and
water-mist-plus-nitrogen fire suppression systems for commercial
airplanes. This program and associated studies are still ongoing and
flight testing is planned for the last quarter of calendar year 2003. The
results of tests on this system are expected to be made public in early
2004, and will
Appendix V
Summaries of Potential Fire Safety
Advancements
help to clarify the possible costs, benefits, and drawbacks of the
combined system.
Additional research, development, and testing will be required before
multisensor technology is ready for use in commercial aviation. NASA, FAA,
and private companies are pursuing various approaches. Some experts
believe that some forms of multisensor technology could be in use in 5
years. When these units become available, questions may arise about where
their use will be required. For example, the Canadian Transportation
Safety Board has recommended that some areas in addition to those
currently designated as fire zones may need to be equipped with
detectors.14 These include the electronics and equipment bay (typically
below the floor beneath the cockpit and in front of the passenger cabin),
areas behind interior wall panels in the cockpit and cabin areas, and
areas behind circuit breaker and other electronic panels.
Water Mist Fire Suppression
Background For over two decades, the aviation industry has evaluated the
use of systems that spray water mist to suppress fires in airliner cabins,
cargo compartments, and engine casings (see fig. 7). This effort was
prompted, in part, by a need to identify an alternative to Halon, the
primary chemical used to extinguish fires aboard airliners. With few
exceptions, Halon is the sole fire suppressant installed in today's
aircraft fire suppression systems. However, the production of Halon was
banned under the 1987 Montreal Protocol on Substances that Deplete the
Ozone Layer, and its use in many noncritical sectors has been phased out.
Significant reserves of Halon remain, and its use is still allowed in
certain "critical use" applications, such as aerospace,15 because no
immediate viable replacement agent
14This recommendation was one of several resulting from the Canadian
Transportation Safety Board's investigation of the Swissair Flight 111
crash.
15A use is considered "critical" when a need exists to protect against
fire or explosion risks in areas that would result in a serious threat to
essential services or pose an unacceptable threat to life, the
environment, or national security. Typical critical users are aerospace,
certain petrochemical production processors, certain marine applications,
and national defense.
Appendix V
Summaries of Potential Fire Safety
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exists. To enable the testing and further development of suitable
alternatives to and substitutes for Halon, FAA has drafted detailed
standards for replacements in the cargo and engine compartments. These
standards typically require replacement systems to provide the same level
of safety as the currently used Halon extinguishing system.
Figure 7: Water Mist Nozzle and Possible Placement
According to FAA and others in the aviation industry, successful water
mist systems could provide benefits against an in-flight or postcrash
fire, including
o cooling the passengers, cabin surfaces, furnishings and overall cabin
temperatures;
o decreasing toxic smoke and irritant gases; and
Appendix V
Summaries of Potential Fire Safety
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o delaying or preventing "flashover" fires from occurring. 16
In addition, a 1996 study prepared for the British Civil Aviation
Authority examined 42 accidents and 32 survivability factors and found
that cabin water spray was the factor that showed the greatest potential
for reducing fatality and injury rates.17 In the early 1990s, a joint FAA
and Civil Aviation Authority study found that cabin water mist systems
would be highly effective in improving survivability during a postcrash
fire.18 However, the cost of using these systems outweighed the benefits,
largely because of the weight of the water that airliners would be
required to carry to operate them. In the mid- and late-1990s, FAA and
others began examining water mist systems in airliner cargo compartments
to help offset the cost of a cabin water mist system because the water
could be used or shared by both the cargo compartment and the cabin.
European and U.S. researchers also designed systems that required much
less water because they targeted specific zones within an aircraft to
suppress fires rather than spraying water throughout the cabin or the
cargo compartment.
In 2000, Navy researchers found a twin-fluid system to be highly reliable
and maintenance-free.19 Moreover, this system's delivery nozzles could be
installed without otherwise changing cabin interiors. The Navy
researchers' report recommended that FAA and NTSB perform follow-up
testing leading to the final design and certification of an interior water
mist fire suppression system for all passenger and cargo transport
aircraft. Also in 2000, a European consortium began a collaborative
research project
16Flashover can occur in an airplane cabin fire when all exposed
combustible surfaces reach ignition temperature more or less
simultaneously. It is characterized by rapid increases in temperature,
with smoke, toxic gases, and oxygen depletion creating a largely
nonsurvivable environment.
17R.G.W. Cherry & Associates, Analysis of Structural Factors Influencing
the Survivability of Occupants in Aeroplane Accidents, Civil Aviation
Authority, Paper 96011 (London: December 1996).
18Increasing the Survival Rate in Aircraft Accidents: Impact Protection,
Fire Survivability, and Evacuation, European Transport Safety Council
(December 1996).
19Twin-fluid systems use air, nitrogen, or another gas in combination with
water. They require lower water supply pressure and bigger nozzle
orifices.
Appendix V
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Advancements
called FIREDETEX, which combines multisensor fire detectors, water mist,
and onboard fuel tank inerting into one fire detection and suppression
system.20
In 2001 and 2002, FAA tested experimental mist systems to determine what
could meet its preliminary minimum performance standards for cargo
compartment suppression systems. A system that combines water mist with
nitrogen met these minimum standards. In this system, water and nitrogen
"knock down" the initial fire, and nitrogen suppresses any deep-seated
residual fire by inerting the entire compartment.21 In cargo compartment
testing, this system maintained cooler temperatures than had either a
plain water mist system or a Halon-based system.
Status Additional research and testing are needed before water mist
technology can be considered for commercial aircraft. For example, the
weight and relative effectiveness of any water mist system would need to
be considered and evaluated. In addition, before it could be used in
aircraft, the consequences of using water will need to be further
evaluated. For example, Boeing officials noted that using a water mist
fire suppression system in the cabin in a post crash fire might actually
reduce passenger safety if the mist or fog creates confusion among the
passengers, leading to longer evacuation times. Further, of concern is the
possible shorting of electrical wiring and equipment and damage to
aircraft interiors (e.g., seats, entertainment equipment, and insulation).
Water cleanup could also be difficult and require special drying
equipment.
20Inerting involves reducing flammability in fuel tanks, which is
discussed separately in this report.
21Boeing commented that this more recent system would not pass the
original cargo minimum performance standard, and Boeing disagrees with
FAA's relaxing of the original standard.
Appendix V
Summaries of Potential Fire Safety
Advancements
Fire-Safe Fuels
Background Burning fuel typically dominates and often overwhelms postcrash
fire scenarios and causes even the most fire-resistant materials to
burn.22 Fuel spilled from tanks ruptured upon crash impact often forms an
easily ignitable fuel-air mixture. A more frequent fuel-related problem is
the fuel tank explosion, in which a volatile fuel-air mixture inside the
fuel tank is ignited, often by an unknown source. For example, it is
believed that fuel tank explosions destroyed a Philippines Air 737 in
1990, TWA Flight 800 in 1996, and a Thai Air 737 in 2001. Therefore,
reducing the flammability of fuel could improve survivability in postcrash
fires as well as reduce the occurrence of fuel tank explosions.
Reducing fuel flammability involves limiting the volatility23 of fuel and
the rate at which it vaporizes.24 Liquid fuel can burn only when enough
fuel vapor is mixed with air. If the fuel cannot vaporize, a fire cannot
occur. This principle is behind the development of higher-flashpoint fuel,
whose use can decrease the likelihood of a fuel tank explosion. The flash
point is the lowest temperature at which a liquid fuel produces enough
vapor to ignite in the presence of a source of ignition-the lower the
flash point, the greater the risk of fire. If the fuel is volatile enough,
however, and air is sucked into the fuel tank area upon crash impact,
limiting the fuel's vaporization can prevent a burnable mixture from
forming. This principle supports the use of additives that modify the
viscosity of fuel to limit postcrash fires; for example, antimisting
kerosene contains such additives.
22An average widebody aircraft carries 50,000 gallons of aviation fuel at
takeoff.
23Fuels function by releasing combustible gases. Indicators of volatility
include a fuel's boiling point (the higher the boiling point, the less
volatile the fuel) and vapor pressure (the higher the vapor pressure, the
more volatile the fuel). Therefore, raising the temperature can increase
volatility. A highly volatile fuel is more likely to form a flammable or
explosive mixture with air than a nonvolatile fuel. By definition, gases
are volatile. Liquid fuels either are sufficiently volatile at room
temperature to produce combustible vapor (ethanol, petrol) or they produce
sufficient combustible vapors when heated (kerosene).
24The fuel vaporization rate is the minimum temperature to which the pure
liquid fuel must be heated so that the vapor pressure is high enough for
an explosive mixture to be formed with air--then the liquid is allowed to
evaporate and is brought into contact with a flame, spark, or hot
filament. Flash points are lower than ignition temperatures.
Appendix V
Summaries of Potential Fire Safety
Advancements
According to FAA and NASA, however, these additives do nothing to prevent
fuel tank explosions.
From the early 1960s to the mid-1980s, FAA conducted research on fuel
safety. The Aviation Safety Act of 1988 required that FAA undertake
research on low-flammability aircraft fuels, and, in 1993, FAA developed
plans for fuel safety research. In 1996, a National Research Council
experts' workshop on aviation fuel summarized existing fuel safety
research efforts. The participants concluded that although postcrash
fuel-fed aircraft fires had been researched, limited progress had been
achieved and little work had been published.
As part of FAA's research, fuels have been modified with thickening
polymer additives to slow down vaporization in crashes. Participants in
the 1996 National Research Council workshop identified several long-term
research goals for consideration in developing modified fuels and fuel
additives to improve fire safety. They also agreed that a combination of
effective fire-safe fuel additives could probably be either selected or
designed, provided that fuel performance requirements were identified in
advance. In addition, they agreed that existing aircraft designs that
reduce the chance of fuel igniting do not present major barriers to the
implementation of a fire-safe fuel.
A 1996 European Transport Safety Council report suggested that antimisting
kerosene be at least partially tested on regular military transport
flights (e.g., in one tank, feeding one engine) to demonstrate its
operational compatibility. The report also recommended the consideration
of a study comparing the costs of the current principal commercial fuel
and the special, higher-flashpoint fuel used by the Navy. According to
NASA and FAA fire-safe fuels experts, military fuel is much harder to burn
in storage or to ignite in a pan because of its lower volatility; however,
it is just as flammable as aviation fuel when it is sprayed into an engine
combustor.
Status Fire-safe fuels are not currently available and are in the early
stages of research and development. In January 2002, NASA opened a
fire-safe fuels research branch at its Glenn Research Center in Ohio.
NASA-Glenn is conducting aviation fuel research that evaluates fuel vapor
flammability in conjunction with FAA's fuel tank inerting program,
including the measurement of fuel "flash points." NASA is examining the
effects of
Appendix V
Summaries of Potential Fire Safety
Advancements
surfactants, gelling agents, and chemical composition changes on the
vaporization and pressure characteristics of jet fuel.25
In addition to FAA's and NASA's research, some university and industry
researchers have made progress in developing fire-safe fuels. Many use
advanced analytical, computational modeling technologies to inform their
research. A council of producers and users of fuels is also coordinating
research on ways to use such fuels. NASA fuel experts remain optimistic
that small changes in fuel technologies can have a big impact on fuel
safety.
Developing fire-safe fuels will require much more research and testing.
There are significant technical difficulties associated with creating a
fuel that meets aviation requirements while meaningfully decreasing the
flammability of the fuel.
Thermal Acoustic Insulation Materials
Background To keep an airplane quieter and warmer, a layer of thermal
acoustic insulation material is connected to paneling and walls throughout
the aircraft. This insulation, if properly designed, can also prevent or
limit the spread of an in-flight fire. In addition, thermal acoustic
insulation provides a barrier against a fire burning through the cabin
from outside the airplane's fuselage (See fig. 8.). Such a fire, often
called a postcrash fire, may occur when fuel is spilled on the ground
after a crash or an impact.
25A surfactant, or surface-active agent, is a soluble compound that
reduces the surface tension of liquids, or reduces interfacial tension
between two liquids or a liquid and a solid. A gelling agent is a fuel
"thickener."
Appendix V
Summaries of Potential Fire Safety
Advancements
Figure 8: Fire Insulation Blankets
While this thermal acoustic insulation material could help prevent the
spread of fire, some of the insulation materials that have been used in
the past have contributed to fires. For example, FAA indicated that an
insulation material, called metallized Mylar(R), contributed to at least
six in-flight fires. Airlines have stopped using this material and are
removing it from existing aircraft.
FAA's two main efforts in this area are directed toward preventing fatal
in-flight fire and improving postcrash fire survivability.
o Since 1998, FAA has been developing test standards for preventing
in-flight fires in response to findings that fire spread on some thermal
acoustic insulation blanket materials. In 2000, FAA issued a notice of
proposed rule-making that outlined new flammability test criteria for
in-flight fires. FAA's in-flight test standards require thermal acoustic
Appendix V
Summaries of Potential Fire Safety
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insulation materials to protect passengers. According to the standards,
insulation materials installed in airplanes will not propagate a fire if
ignition occurs.
o FAA is also developing more stringent burnthrough test standards for
postcrash fires. FAA has been studying the penetration of the fuselage by
an external fire-known as fuselage burnthrough-since the late 1980s and
believes that improving the fire resistance of thermal acoustic insulation
could delay fuselage burnthrough. In laboratory tests conducted from 1999
through 2002, an FAA-led working group determined that insulation is the
most potentially effective and practical means of delaying the spread of
fire or creating a barrier to burnthrough. In 2002, FAA completed draft
burnthrough standards outlining a proposed methodology for testing thermal
acoustic insulation. The burnthrough standards would protect passengers
and crews by extending by at least 4 minutes the time available for
evacuation in a postcrash fire.
Various studies have estimated the potential benefits from both test
standards:
o A 1999 study of worldwide aviation accidents from 1966 through 1993
estimated that about 10 lives per year would have been saved if protection
had provided an additional 4 minutes for occupants to exit the airplane.
o A 2000 FAA study estimated that about 37 U.S. fatalities would be
avoided between 2000 and 2019 through the implementation of both proposed
standards.26
o A 2002 study by the British Civil Aviation Authority of worldwide
aviation accidents from 1991 through 2000 estimated that at least 34 lives
per year would have been saved if insulation had met both proposed
standards.
26FAA's benefit estimate, based on $2.7 million per life saved, ranges
from $37.7 million to $231.5 million, discounted to present value, based
partially on 37.2 deaths avoided from its 2000 study. FAA could not
quantify benefits from flame propagation requirements, but indicated that
avoiding an accident with 169 passenger fatalities would avert a $231.5
million loss (not including the cost of the plane).
Appendix V
Summaries of Potential Fire Safety
Advancements
Status Insulation designed to replace metallized Mylar(R) is currently
available. A 2000 FAA airworthiness directive gave the airlines 5 years to
remove and replace metallized Mylar(R) insulation in 719 affected
airplanes. Replacement insulation is required to meet the in-flight
standard and will be installed in these airplanes by mid-2005. In that
airworthiness directive, FAA indicated that it did not consider other
currently installed insulation to constitute an unsafe condition.
Thermal acoustic insulation is currently available for installation on
commercial airliners. This insulation has been demonstrated to reduce the
chance of fatal in-flight fires and to improve postcrash fire
survivability. On July 31, 2003, FAA issued a final rule requiring that
after September 2, 2005, all newly manufactured airplanes having a seating
capacity of more than 20 passengers or over 6,000 pounds must use thermal
acoustic insulation that meets more stringent standards for how quickly
flames can spread.27 In addition, for aircraft of this size manufactured
before September 2, 2003, replacement insulation in the fuselage must also
meet the new, higher standard.
Research is continuing to develop thermal acoustic insulation that
provides better in-flight and burnthrough protection. Even when this
material is available, the high cost of retrofitting airplanes may limit
its use to newly manufactured aircraft. For example, FAA estimates that
the metallized Mylar(R) retrofit alone will cost a total of $368.4
million, discounted to present value terms, for the 719 affected
airplanes. Because thermal acoustic insulation is installed throughout the
pressurized section of the airplane for the life of its service,
retrofitting the entire fleet would cost several billion dollars.
Ultra-Fire-Resistant Polymers
Background Polymers are used in aircraft in the form of lightweight
plastics and composites and are selected on the basis of their estimated
installed cost,
27Improved Flammability Standards for Thermal/Acoustic Insulation
Materials Used in Transport Category Airplanes; Final Rule, FAA/DOT (14
C.F.R. parts 25, 91, et al.).
Appendix V
Summaries of Potential Fire Safety
Advancements
weight, strength, and durability. Most of the aircraft cabin is made of
polymeric material. In the event of an in-flight or a postcrash fire, the
use of polymeric materials with reduced flammability could give passengers
and crew more time to evacuate by delaying the rate at which the fire
spreads through the cabin.
FAA researchers are developing better techniques to measure the
flammability of polymers and to make polymers that are ultra fire
resistant. Developing these materials is the long-term goal of FAA's Fire
Research Program, which, if successful, will "eliminate burning cabin
materials as a cause of death in aircraft accidents." Materials being
improved include composite and adhesive resins, textile fibers, rubber for
seat cushions, and plastics for molded parts used in seats and passenger
electronics. (See fig. 9.)
Figure 9: Flammable Cabin Materials and Small-scale Material Test Device
Adding flame-retardant substances to existing materials is one way to
decrease their flammability. For example, some manufacturers add
substances that release water when they reach a high temperature. When a
material, such as wiring insulation, is heated or burns, the water acts to
absorb the heat and cools down the fire. Other materials are designed to
become surface-scorched on exposure to fire, causing a layer of char to
protect the rest of the material from burning. Lastly, adding a type of
clay can have a flame-retardant effect. In general, these fire-retardant
polymers are formulated to pass an ignition test but do not meet FAA's
criterion for ultra fire resistance, which is a 90 percent reduction in
the rate at which the
Appendix V
Summaries of Potential Fire Safety
Advancements
untreated material would burn. To meet this strict requirement, FAA is
developing new "smart" polymers that are typical plastics under normal
conditions but convert to ultra-fire-resistant materials when exposed to
an ignition source or fire.
FAA has adopted a number of flammability standards over the last 30 years.
In 1984, FAA passed a retrofit rule that replaced 650,000 seat cushions
with flame-retardant seat cushions at a total cost of about $75 million.
The replacement seat cushions were found to delay cabin flashover by 40 to
60 seconds. Fire-retardant seat cushions can also prevent ramp and
in-flight fires that originate at a seat and would otherwise burn out of
control if left unattended. In 1986 and 1988, FAA set maximum allowable
levels of heat and smoke from burning interior materials to decrease the
amount of smoke that they would release in a postcrash fire. These
standards affected paneling in all newly manufactured aircraft. Airlines
and airframe manufacturers invested several hundred million dollars to
develop these new panels.
Status Ultra-fireresistant polymers are not currently available for use on
commercial airliners. These polymers are still in the early stages of
research and development. To reduce the cost and simplify the testing of
new materials, FAA is employing a new technique to characterize the
flammability and thermal decomposition of new products; this technique
requires only a milligram of sample material. The result has been the
discovery of several new compositions of matter (including "smart"
polymers). The test identifies key thermal and combustion properties that
allow rapid screening of new materials.28 From these materials, FAA plans
to select the most promising and work with industry to make enough of the
new polymers to fabricate full-scale cabin components like sidewalls and
stowage bins for fire testing.
FAA's phased research program includes the selection in 2003 of a small
number of resins, plastics, rubbers, and fibers on the basis of their
functionality, cost, and potential to meet fire performance guidelines. In
2005, FAA plans to fabricate decorative panels, molded parts, seat
cushions, and textiles for testing from 2007 through 2010. Full-scale
testing
28These methods test the heat release rate, total heat of combustion of
the volatiles, thermal stability, char yield, decomposition process, and
rate of decomposition.
Appendix V
Summaries of Potential Fire Safety
Advancements
is scheduled for 2011 but is contingent upon the availability of program
funds and commercial interest from the private sector.
Research continues on ultra-fire-resistant polymers that will increase
protection against in-flight fires and cabin burnthrough. According to an
FAA fire research expert, issues facing this research include (1) the
current high cost of ultra-fire-resistant polymers; (2) difficulties in
producing ultra-fire-resistant polymers with low to moderate processing
temperatures, good strength and toughness, and colorability and
colorfastness; and (3) gaps in understanding the relationship between
material properties and fire performance and between chemical composition
and fire performance, scaling relationships, and fundamental
fire-resistance mechanisms. In addition, once the materials are developed
and tested, getting them produced economically and installed in aircraft
will become an issue. It is expected that such new materials with ultra
fire resistance would be more expensive to produce and that the market for
such materials would be uncertain.
Airport Rescue and Fire-Fighting Operations
Background Because of the fire danger following a commercial airplane
crash, having airport rescue and fire-fighting operations available can
improve the chances of survival for the people involved. Most airplane
accidents occur during takeoff or landing at the airport or in the
surrounding community. A fire outside the airplane, with its tremendous
heat, may take only a few minutes to burn through the airplane's outside
shell. According to FAA, firefighters are responsible for creating an
escape path by spraying water and chemicals on the fire to allow the
passengers and crew to evacuate the airplane. Firefighters use one or more
trucks to extinguish external fires, often at great personal risk, and use
hand-held attack lines when attempting to put out fires within the
airplane fuselage. (See fig. 10). Fires within the fuselage are considered
difficult to control with existing equipment and procedures because they
involve complex conditions, such as smoke-laden toxic gases and high
temperatures in the passenger cabin. FAA has taken actions to control both
internal and external postcrash fires,
Appendix V
Summaries of Potential Fire Safety
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including requiring major airports to have airport rescue and
fire-fighting operations.
In 1972, FAA first proposed regulations to ensure that major airports have
a minimal level of airport rescue and fire-fighting operations. Some
changes to these regulations were made in 1988. The regulations establish,
among other things, equipment standards, annual testing requirements for
response times, and operating procedures. The requirements depend on both
the size of the airport and the resources the locality has agreed to make
available as needed.
In 1997, FAA compared airport rescue and fire-fighting missions and
standards for civilian airports with DOD's for defense installations and
reported that DOD's requirements were not applicable to civilian airports.
In 1988, and again in 1998, Transport Canada Civil Aviation also studied
its rescue and fire-fighting operations and concluded that the expenditure
of resources for such unlikely occurrences was difficult to justify from a
benefit-cost perspective. This conclusion highlighted the conflict between
safety and cost in attempting to define rescue and fire-fighting
requirements.
A coalition of union organizations and others concerned about aviation
safety released a report critical of FAA's standards and operational
regulations in 1999. According to the report, FAA's airport rescue and
fire-fighting regulations were outdated and inadequate.
Appendix V
Summaries of Potential Fire Safety
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Status In 2002, FAA incorporated measures recommended by NTSB into FAA's
Aeronautical Information Manual Official Guide to Basic Flight Information
and Air Traffic Control Procedures.29 These measures (1) designate a radio
frequency at most major airports to allow direct communication between
airport rescue and fire-fighting personnel and flight crewmembers in the
event of an emergency and (2) specify a universal set of hand signals for
use when radio communication is lost.
In March 2001, FAA responded to the reports criticizing its airport rescue
and fire-fighting standards by tasking its Aviation Regulatory Advisory
Committee to review the agency's rescue and fire-fighting requirements to
identify measures that could be added, modified, or deleted. In 2003, the
committee is expected to propose requirements for the number of trucks,
the amount of fire extinguishing agent, vehicle response times, and
staffing at airports and to publish its findings in a notice of proposed
rule-making. Depending on the results of this FAA review, additional
resources may be needed at some airports. The overall cost of improving
airport rescue and fire-fighting response capabilities could be a
significant barrier to the further development of regulations. For
example, some in the aviation industry are concerned about the costs of
extending requirements to smaller airports and of appropriately equipping
all airports with resources. According to FAA, extending federal safety
requirements to some smaller airports would cost at least $2 million at
each airport initially and $1 million annually thereafter.
29This manual is designed to provide the aviation community with basic
flight information and air traffic control procedures for use in the
National Airspace System of the United States.
Appendix VI
Summaries of Potential Improved Evacuation Safety Advancements
This appendix presents information on the background and status of
potential advancements in evacuation safety that we identified, including
the following:
o improved passenger safety briefings;
o exit seat briefings;
o photo-luminescent floor track marking;
o crewmember safety and evacuation training;
o acoustic attraction signals;
o smoke hoods;
o exit slide testing; o overwing exit doors;
o evacuation procedures for very large transport aircraft; and
o personal flotation devices.
Passenger Safety Briefings
Background Federal regulations require that passengers receive an oral
briefing prior to takeoff on safety aspects of the upcoming flight. FAA
also requires that oral briefings be supplemented with printed safety
briefing cards that pertain only to that make and model of airplane and
are consistent with the air carrier's procedures. These two safety
measures must include information on smoking, the location and operation
of emergency exits, seat belts, compliance with signs, and the location
and use of flotation devices. In addition, if the flight operates above
25,000 feet mean sea level, the briefing and cards must include
information on the emergency use of oxygen.
FAA published an Advisory Circular in March 1991 to guide air carriers'
development of oral safety briefings and cards. Primarily, the circular
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Summaries of Potential Improved Evacuation
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defines the material that must be covered and suggests material that FAA
believes should be covered. The circular also discusses the difficulty in
motivating passengers to attend to the safety information and suggests
making the oral briefing and safety cards as attractive and interesting as
possible to increase passengers' attention. The Advisory Circular
suggests, for example, that flight attendants be animated, speak clearly
and slowly, and maintain eye contact with the passengers. Multicolored
safety cards with pictures and drawings should be used over black and
white cards. Finally, the circular suggests the use of a recorded
videotape briefing because it ensures a complete briefing with good
diction and allows for additional visual information to be presented to
the passengers. (See fig. 11.)
Status Despite efforts to improve passengers' attention to safety
information, a large percentage of passengers continue to ignore preflight
safety briefings and safety cards, according to a study NTSB conducted in
1999. Of 457
Appendix VI
Summaries of Potential Improved Evacuation
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passengers polled, 54 percent (247) reported that they had not watched the
entire briefing because they had seen it before. An additional 70
passengers indicated that the briefing provided common knowledge and
therefore there was no need to watch it. Of 431 passengers who answered a
question about whether they had read the safety card, 68 percent (293)
indicated that they had not, many of them stating that they had read
safety cards on previous flights.
Safety briefings and cards serve an important safety purpose for both
passengers and crew. They are intended to prepare passengers for an
emergency by providing them with information about the location and
operation of exits and emergency equipment that they may have to
operate-and whose location and operation may differ from one airplane to
the next. Well-briefed passengers will be better prepared in an emergency,
thereby increasing their chances of surviving and lessening their
dependence on the crew for assistance.
In its emergency evacuation study, NTSB recommended that FAA instruct
airlines to "conduct research and explore creative and effective methods
that use state-of-the-art technology to convey safety information to
passengers."1 NTSB further recommended "the presented information include
a demonstration of all emergency evacuation procedures, such as how to
open the emergency exits and exit the aircraft, including how to use the
slides." That research found that passengers often view safety briefings
and cards as uninteresting and the information as intuitive. FAA has
requested that commercial carriers explore different ways to present the
materials to their passengers, adding that more should be done to educate
passengers about what to do after an accident has occurred.
Exit Seat Briefing
Background Passengers seated in an exit row may be called on to assist in
an evacuation. Upon a crewmember's command or a personal assessment of
danger, these passengers must decide if their exit is safe to use and then
open their exit hatch or door for use during an evacuation. In October
1990,
1NTSB, Safety Study: Emergency Evacuation of Commercial Airlines,
[A-00-86] (Washington, D.C.: 2001).
Appendix VI
Summaries of Potential Improved Evacuation
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FAA required airlines to actively screen passengers occupying exit seats
for "suitability" and to administer one-on-one briefings on their
responsibilities. This rule does not require specific training for exit
seat occupants, but it does require that the occupants be duly informed of
their distinct obligations.
Status According to NTSB, preflight briefings of passengers in exit rows
could contribute positively to a passenger evacuation. In a 1999 study,
NTSB found that the individual briefings given to passengers who occupy
exit seats have a positive effect on the outcome of an aircraft
evacuation. The studies also found that as a result of the individualized
briefings, flight attendants were better able to assess the suitability of
the passengers seated in the exit seats.
According to FAA's Flight Standards Handbook Bulletin for Air
Transportation, several U.S. airlines have identified specific cabin
crewmembers to perform "structured personal conversations or briefings,"
designed to equip and prepare passengers in exit seats beyond the general
passenger briefing. Also, the majority of air carriers have procedures to
assist crewmembers with screening passengers seated in exit rows.
FAA's 1990 rule requires that passengers seated in exit rows be provided
with information cards that detail the actions to be taken in the case of
an emergency. However, individual exit row briefings, such as those
recommended by NTSB, are not required. Also included on the information
cards are provisions for a passenger who does not wish to be seated in the
exit row to be reseated. Additionally, carriers are required to assess the
exit row passenger's ability to carry out the required functions. The
extent of discussion with exit row passengers depends on each airline's
policy.
Photo-luminescent Floor Track Marking
Background In June 1983, an Air Canada DC-9 flight from Dallas to Toronto
was cruising at 33,000 feet when the crew reported a lavatory fire. An
emergency was declared, and the aircraft made a successful emergency
landing at the Cincinnati Northern Kentucky International Airport. The
crew initiated an
Appendix VI
Summaries of Potential Improved Evacuation
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evacuation, but only half of the 46 persons aboard were able to escape
before becoming overcome by smoke and fire. In its investigation of this
accident, NTSB learned that many of the 23 passengers who died might have
benefited from floor tracking lighting. As a result, NTSB recommended that
airlines be equipped with floor-level escape markings. FAA determined that
floor lighting could improve the evacuation rate by 20 percent under
certain conditions, and FAA now requires all airliners to have a row of
lights along the floor to guide passengers to the exit should visibility
be reduced by smoke.
On transport category aircraft, these escape markings, called floor
proximity marking systems, typically consist primarily of small electric
lights spaced at intervals on the floor or mounted on the seat assemblies,
along the aisle. The requirement for electricity to power these systems
has made them vulnerable to a variety of problems, including battery and
wiring failures, burned-out light bulbs, and physical disruption caused by
vibration, passenger traffic, galley cart strikes, and hull breakage in
accidents. Attempts to overcome these problems have led to the proposal
that nonelectric, photo-luminescent (glow-in-the-dark) materials be used
in the construction of floor proximity marking systems. The elements of
these new systems are "charged" by the normal airplane passenger cabin
lighting, including the sunlight that enters the cabin when the window
shades are open during daylight hours. (See fig. 12.)
Appendix VI
Summaries of Potential Improved Evacuation
Safety Advancements
Status Floor track marking using photo-luminescent materials is currently
available but not required for U.S. commercial airliners. Performance
demonstrations of photo-luminescent technology have found that strontium
aluminate photo-luminescent marking systems can be effective in providing
the guidance for egress that floor proximity marking systems are intended
to achieve. According to industry and government officials, such
photo-luminescent marking systems are also cheaper to install than
electric light systems and require little to no maintenance. Moreover,
photo-luminescent technology weighs about 15 to 20 pounds less than
electric light systems and, unlike the electric systems, illuminates both
sides of the aisle, creating a pathway to the exits.
Appendix VI
Summaries of Potential Improved Evacuation
Safety Advancements
Photo-luminescent floor track marking technology is mature and is
currently being used by a small number of operators, mostly in Europe. In
the United States, Southwest Airlines has equipped its entire fleet with
the photo-luminescent system. However, the light emitted from
photo-luminescent materials is not as bright as the light from
electrically operated systems. Additionally, the photo-luminescent
materials are not as effective when they have not been exposed to light
for an extended period of time, as after a long overseas nighttime flight.
The estimated retail price of an entire system, not including the
installation costs, is $5,000 per airplane.
Crewmember Safety and Evacuation Training
Background FAA requires crewmembers to attend annual training to
demonstrate their competency in emergency procedures. They have to be
knowledgeable and efficient while exercising good judgment. Crewmembers
must know their own duties and responsibilities during an evacuation and
be familiar with those of their fellow workers so that they can take over
for others if necessary.
The requirements for emergency evacuation training and demonstrations were
first established in 1965. Operators were required to conduct full-scale
evacuation demonstrations, include crewmembers in the demonstrations, and
complete the demonstrations in 2 minutes using 50 percent of the exits.
The purpose of the demonstrations was to test the crewmembers' ability to
execute established emergency evacuation procedures and to ensure the
realistic assignment of functions to the crew. A full-scale demonstration
was required for each type and model of airplane when it first started
passenger-carrying operations, increased its passenger seating capacity by
5 percent or more, or underwent a major change in the cabin interior that
would affect an emergency evacuation. Subsequently, the time allowed to
evacuate the cabin during these tests was reduced to 90 seconds.
The aviation community took steps in the 1990s to develop a program called
Crew Resource Management that focuses on overall improvements in
crewmembers' performance and flight safety strategies, including those
Appendix VI
Summaries of Potential Improved Evacuation
Safety Advancements
for evacuation. FAA officials told us that they plan to emphasize the
importance of effective communication between crewmembers and are
considering updating a related Advisory Circular. Effective communication
between cockpit and cabin crew are particularly important with the added
security precautions being taken after September 11, 2001, including the
locking the cockpit door during flight.
Status The traditional training initiative now has an advanced curriculum,
Advanced Crew Resource Management. According to FAA, this comprehensive
implementation package includes crew resource management procedures,
training for instructors and evaluators, training for crewmembers, a
standardized assessment of the crew's performance, and an ongoing
implementation process. This advanced training was designed and developed
through a collaborative effort between the airline and research
communities. FAA considers training to be an ongoing development process
that provides airlines with unique crew resource management solutions
tailored to their operational demands. The design of crew resource
management procedures is based on principles that require an emphasis on
the airline's specific operational environment. The procedures were
developed to emphasize these crew resource management elements by
incorporating them into standard operating procedures for normal as well
as abnormal and emergency flight situations.
Because commercial airliner accidents are rare, crewmembers must rely on
their initial and recurrent training to guide their actions during an
emergency. Even in light of advances and initiatives in evacuation
technology, such as slides and slide life rafts, crewmembers must still
assume a critical role in ensuring the safe evacuation of their
passengers. Airline operators have indicated that it is very costly for
them to pull large numbers of crewmembers off-line to participate in
training sessions.
FAA officials told us that improving flight and cabin crew communication
holds promise for ensuring the evacuation of passengers during an
emergency. To improve this communication and coordination between flight
and cabin crew, FAA plans to update the related Advisory Circular, oversee
training, and charge FAA inspectors with monitoring air carriers during
flights to see that improvements are being implemented. In addition, FAA
is enhancing its guidance to air carriers on preflight briefings for
flight crews to sharpen their responses to emergency situations and
mitigate passengers' confusion. FAA expects this guidance to bolster the
use and quality of preflight briefings between pilots and flight
attendants on
Appendix VI
Summaries of Potential Improved Evacuation
Safety Advancements
security, communication, and emergency procedures. According to FAA, these
briefings have been shown to greatly improve the flight crew's safety
mind-set and to enhance communication.
Acoustic Attraction Signals
Background Acoustic attraction signals make sounds to help people locate
the doors in smoke, darkness, or when lights and exit signs are obscured.
When activated, the devices are intended to help people to determine the
direction and approximate distance of the sound-and of the door. Examples
of audio attraction signals include recorded speech sounds, broadband
multifrequency sounds ("white noise"), or alarm bells.
Research to determine if acoustic attraction signals can be useful in
aircraft evacuation has included, for example, FAA's Civil Aeromedical
Institute testing of recorded speech sounds in varying pitches, using
phrases such as "This way out," "This way," and "Exit here." Researchers
at the University of Leeds developed Localizer Directional Sound beacons,
which combine broadband, multifrequency "white noise" of between 40Hz and
20kHz with an alerting sound of at least one other frequency, according to
the inventor (see fig. 13).
Note: Acoustic signaling device is of the type used near building exits.
Appendix VI
Summaries of Potential Improved Evacuation
Safety Advancements
The FAA study noted above of acoustic attraction signals found that in the
absence of recorded speech signals, the majority of participants
evacuating a low-light-level, vision-obscured cabin will head for the
front exit or will follow their neighbors. In contrast, participants
exposed to recorded speech sounds will select additional exits, even those
in the rear of the airplane. During aircraft trials conducted by Cranfield
University and University of Greenwich researchers, tests of directional
sound beacons found that under cabin smoke conditions, exits were used
most efficiently when the cabin crew gave directions and the directional
sound beacons were activated. With this combination, the distribution of
passengers to the available exits was better than with cabin crew
directions alone, sound beacons alone, no cabin crew directions, or no
sound beacons. Researchers found that passengers were able to identify and
move toward the closest sound source inside the airplane cabin and to
distinguish between two closely spaced loudspeakers. However, in 2001,
Airbus conducted several evacuation test trials of audio attraction
signals using an A340 aircraft. According to Airbus, the acoustic
attraction signals did not enhance passengers' orientation, and, overall,
did not contribute to passengers' safety.
Status While acoustic attraction signals are currently available, further
research is needed to determine if their use is warranted on commercial
airliners. FAA, Transport Canada Civil Aviation, and the British Civilian
Aviation Authority do not currently mandate the use of acoustic attraction
signals. The United Kingdom's Air Accidents Investigation Branch made a
recommendation after the fatal Boeing 737 accident at Manchester
International Airport in 1985 that research be undertaken to assess the
viability of audio attraction signals and other evacuation techniques to
assist passengers impaired by smoke and toxic or irritant gases. The
Civilian Aviation Authority accepted the recommendation and sponsored
research at Cranfield University; however, it concluded from the research
results that the likely benefit of the technology would be so small that
no further action should be taken, and the recommendation was closed in
1992.
The French Direction Generale de l'Aviation Civile funded aircraft
evacuation trials using directional sound beacons in November 2002, with
oversight by the European Joint Aviation Authorities. The trials were
conducted at Cranfield University's evacuation simulator with British
Airways cabin crew and examined eight trial evacuations by two groups of
`passengers.' The study surveyed the participants' views on various
aspects of their evacuation experience and measured the overall time to
evacuate.
Appendix VI
Summaries of Potential Improved Evacuation
Safety Advancements
The speed of evacuation was found to be biased by the knowledge
passengers' gained in the four successive trials, and by variations in the
number of passengers participating on the 2 days (155 and 181). The four
trials by each of the two groups of passengers also involved different
combinations of crew and sound in each. The study concluded that the
insufficient number of test sessions further contributed to bias in the
results, and that further research would be needed to determine whether
the devices help to speed overall evacuation.
Further research and testing are needed before acoustic attraction signals
can be considered for widespread airline use. The signals may have
drawbacks that would need to be addressed. For example, the Civil Aviation
Authority found that placing an audio signal in the bulkhead might
disorient or confuse the first few passengers who have to pass and then
move away from the sound source to reach the exit. Such hesitation slowed
passengers' evacuation during testing. The researchers at Cranfield
University trials in 1990 concluded that an acoustic sound signal did not
improve evacuation times by a statistically significant amount, suggesting
that the device might not be cost-effective.
Smoke Hoods
Background Smoke hoods are designed to provide the user with breathable,
filtered air in an environment of smoke and toxic gases that would
otherwise be incapacitating. More people die from smoke and toxic gases
than from fire after an air crash. Because only a few breaths of the
dense, toxic smoke typically found in aircraft fires can render passengers
unconscious and prevent their evacuation, the wider use of smoke hoods has
been investigated as a means of preventing passengers from being overcome
by smoke and of giving them enough breathable air to evacuate. However,
some studies have found that smoke hoods are only effective in certain
types of fires and in some cases may slow the evacuation of cabin
occupants.
As shown in figure 14, a filter smoke hood can be a transparent bag worn
over the head that fits snugly at the neck and is coated with
fire-retardant material; it has a filter but no independent oxygen source
and can provide breathable air by removing some toxic contaminants from
the air for a period ranging from several minutes to 15 minutes, depending
on the
Appendix VI
Summaries of Potential Improved Evacuation
Safety Advancements
severity and type of air contamination. The hood has a filter to remove
carbon monoxide-a main direct cause of death in fire-related commercial
airplane accidents, as well as hydrogen cyanide-another common cause of
death, sometimes from incapacitation that can prevent evacuation. Hoods
also filter carbon dioxide, chlorine, ammonia, acid gases such as hydrogen
chloride and hydrogen sulfide, and various hydrocarbons, alcohols, and
other solvents. Some hoods also include a filter to block particulate
matter. One challenge is where to place the hoods in a highly accessible
location near each seat.
Appendix VI
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Safety Advancements
Certain smoke hoods have been shown to filter out many contaminants
typically found in smoke from an airplane cabin fire and to provide some
temporary head protection from the heat of fire. In a full-scale FAA test
of cabin burnthrough, toxic gases became the driving factor determining
survivability in the forward cabin, reaching lethal levels minutes before
the smoke and temperature rose to unsurvivable levels.
A collaborative effort to estimate the potential benefits of smoke hoods
was undertaken in 1986 by the British Civil Aviation Authority (CAA), the
Appendix VI
Summaries of Potential Improved Evacuation
Safety Advancements
Federal Aviation Administration, the Direction Generale de l'Aviation
Civile (France) and Transport Canada Civil Aviation. The resulting 1987
study examined the 20 accidents where sufficient data was available out of
74 fire-related accidents worldwide from 1966 to 1985. The results were
sensitive to assumptions regarding extent of use and delays due to putting
on smoke hoods. The study concluded that smoke hoods could significantly
extend the time available to evacuate an aircraft and would have saved
approximately 179 lives in the 20 accidents studied, assuming no delay in
donning smoke hoods. Assuming a 10 percent reduction in the evacuation
rate due to smoke hood use would have resulted in an estimated 145 lives
saved in the 20 accidents with adequate data. A 15 second delay in donning
the hoods would have saved an estimated 97 lives in the 20 accidents.2
When the likelihood of use of smoke hoods was included in the analysis for
each accident, the total net benefit was estimated at 134 lives saved in
the 20 accidents. The study also estimated that an additional 228 lives
would have been saved in the 54 accidents where less data was available,
assuming no delay in evacuation.3
The U.S. Air Force and a major manufacturer are developing a drop-down
smoke hood with oxygen. Because current oxygen masks in airplanes are not
airtight around the mouth, they provide little protection from toxic gases
and smoke in an in-flight fire. To provide protection from these hazards,
as well as from decompression and postcrash fire and smoke, the Air
Force's drop-down smoke hood with oxygen uses the airplane's existing
oxygen system and can fit into the overhead bin of a commercial airliner
where the oxygen mask is normally stowed. This smoke hood is intended to
replace current oxygen masks but also be potentially separated from the
oxygen source in a crash to provide time to evacuate.
Status Smoke hoods are currently available and produced by several
manufacturers; however, not all smoke hoods filter carbon monoxide. They
are in use on many military and private aircraft, as well as in buildings.
An
2These estimates assume 100 percent smoke hood use. The net 97 lives saved
with a 15 second delay assumes that smoke hoods would have saved lives in
six accidents and cost lives in four; the net 145 lives saved with a 10
percent reduction in the evacuation rate assumes that smoke hoods would
have saved lives in six accidents and cost lives in two.
3 "Smoke Hoods: Net Safety Benefit Analysis," a collaborative effort by
the Civil Aviation Authority, Federal Aviation Administration, Direction
Generale de l'Aviation Civile, and Transport Canada, London, November
1987, CAA Paper 87017.
Appendix VI
Summaries of Potential Improved Evacuation
Safety Advancements
individually-purchased filter smoke hood costs about $70 or more, but
according to one manufacturer bulk order costs have declined to about $40
per hood. In addition, they estimated that hoods cost about $2 a year to
install and $5 a year to maintain. They weigh about a pound or less and
have to be replaced about every 5 years. Furthermore, airlines could incur
additional replacement costs due to theft if smoke hoods were placed near
passenger seats in commercial aircraft.
Neither the British CAA, the FAA, the DGAC, nor Transport Canada Civil
Aviation has chosen to require smoke hoods. The British Air Accident
Investigations Branch recommended that smoke hoods be considered for
aircraft after the 1985 Manchester accident, in which 48 of 55 passengers
died on a runway from an engine fire before takeoff, mainly from smoke
inhalation and the effects of hydrogen cyanide. Additionally, a U.K.
parliamentary committee recommended research into smoke hoods in 1999, and
the European Transport Safety Council, an international nongovernmental
organization whose mission is to provide impartial advice on
transportation safety to the European Commission and Parliaments,
recommended in 1997 that smoke hoods be provided in all commercial
aircraft. Canada's Transportation Safety Board has taken no official
position on smoke hoods, but has noted a deficiency in cabin safety in
this area and recommended further evaluation of voluntary passenger use.
Although smoke hoods are currently available, they remain controversial.
Passengers are allowed to bring filter type smoke hoods on an airplane,
but FAA is not considering requiring airlines to provide smoke hoods for
passengers. The debate over whether smoke hoods should be installed in
aircraft revolves mainly around regulatory concerns that passengers will
not be able to put smoke hoods on quickly in an emergency; that hoods
might hinder visibility, and that any delay in putting on smoke hoods
would slow down an evacuation. FAA's and CAA's evacuation experiments-to
determine how long it takes for passengers to unpack and don smoke hoods
and whether an evacuation would be slowed by their use-have reached
opposite conclusions about the effects of smoke hoods on evacuation rates.
The CAA has noted that delays in putting on smoke hoods by only one or two
people could jeopardize the whole evacuation. An opposite view by some
experts is that the gas and smoke-induced incapacitation of one or two
passengers could also delay an evacuation.
FAA believes that an evacuation might be hampered by passengers' inability
to quickly and effectively access and don smoke hoods, by
Appendix VI
Summaries of Potential Improved Evacuation
Safety Advancements
competitive passenger behavior, and by a lack of passenger attentiveness
during pre-flight safety briefings. FAA noted that smoke hoods can be
difficult to access and use even by trained individuals. However, other
experts have noted that smoke hoods might reduce panic and help make
evacuations more orderly, that competitive behavior already occurs in
seeking access to exits in a fire, and that passengers could learn smoke
hood safety procedures in the pre-flight safety briefings in the same way
they learn to use drop-down oxygen masks or flotation devices.
The usefulness of smoke hoods varies across fire scenarios depending on
assumptions about how fast hoods could be put on and how much time would
be available to evacuate. One expert told us that the time needed to put
on a smoke hood might not be important in several fire scenarios, such as
an in-flight fire in which passengers are seeking temporary protection
from smoke until the airplane lands and an evacuation can begin. In other
scenarios-a ground evacuation or postcrash evacuation - some experts argue
that passengers in back rows or far from an exit may have their exit path
temporarily blocked as other passengers exit and, because of the delay in
their evacuation, may have a greater need and more time available to don
smoke hoods than passengers seated near usable exits.
Exit Slide Testing
Background Exit slide systems are rarely used during their operational
life span. However, when such a system is used, it may be under adverse
crash conditions that make it important for the system to work as
designed. To prevent injury to passengers and crew escaping through
floor-level exits located more than 6 feet above the ground, assist
devices (i.e., slides or slide-raft systems) are used. (See fig. 15.)
Appendix VI
Summaries of Potential Improved Evacuation
Safety Advancements
The rapid deployment, inflation, and stability of evacuation slides are
important to the effectiveness of an aircraft's evacuation system, as was
illustrated in the fatal ground collision of a Northwest Airlines DC-9 and
a Northwest Airlines 727 in Romulus, Michigan, in December 1990. As a
result of the collision, the DC-9 caught fire, but there were several
slide problems that slowed the evacuation. For example, NTSB later found
that the internal tailcone exit release handle was broken, thereby
preventing the tailcone from releasing and the slide from deploying.
Because of concerns about the operability of exit slides, NTSB recommended
in 1974 that FAA improve its maintenance checks of exit slide operations.
In 1983, FAA revised its exit slide requirements to specify criteria for
resistance to water penetration and absorption, puncture strength, radiant
heat resistance, and deployment as flotation platforms after ditching.
Status All U.S. air carriers have an FAA-approved maintenance program for
each type of airplane that they operate. These programs require that the
components of an airplane's emergency evacuation system, which includes
the exit slides, be periodically inspected and serviced. An FAA principal
maintenance inspector approves the air carrier's maintenance program.
According to NTSB, although most air carriers' maintenance programs
require that a percentage of emergency evacuation slides or slide rafts be
tested for deployment, the percentage of required on-airplane deployments
is generally very small. For example, NTSB found that American Airlines'
FAA-approved maintenance program for the A300 requires an on-airplane
Appendix VI
Summaries of Potential Improved Evacuation
Safety Advancements
operational check of four slides or slide rafts per year. Delta Air Lines'
FAA-approved maintenance program for the L-1011 requires that Delta
activate a full set of emergency exits and evacuation slides or slide
rafts every 24 months. Under an FAA-approved waiver for its maintenance
program, United is not required to deploy any slide on its 737 airplanes.
NTSB also found that FAA allows American Airlines to include inadvertent
and emergency evacuation deployments toward the accomplishment of its
maintenance program; therefore, it is possible that American would not
purposely deploy any slides or slide rafts on an A300 to comply with the
deployment requirement during any given year. In addition, NTSB found that
FAA also allows Delta Air Lines to include inadvertent and emergency
evacuation deployments toward the accomplishment of its maintenance
program.
NTSB holds that because inadvertent and emergency deployments do not occur
in a controlled environment, problems with, or failures in, the system may
be more difficult to identify and record, and personnel qualified to
detect such failures may not be present. For example, in an inadvertent or
emergency slide or slide raft deployment, observations on the amount of
time it takes to inflate the slide or slide raft, and the pressure level
of the slide or slide raft are not likely to be documented. For these
reasons, a 1999 NTSB report said that FAA's allowing these practices could
potentially leave out significant details about the interaction of the
slide or slide raft with the door or how well the crew follows its
training mock-up procedures. Accordingly, in 1999, NTSB recommended that
FAA stop allowing air carriers to count inadvertent and emergency
deployments toward meeting their maintenance program requirement because
conditions are not controlled and important information (on, for example,
the interface between the airplane and the evacuation slide system,
timing, durability, and stability) is not collected. The recommendation
continues to be open at the NTSB. NTSB officials said they would be
meeting to discuss this recommendation with FAA in the near future.
Additionally, NTSB recommended that FAA, for a 12-month period, require
that all operators of transport-category aircraft demonstrate the
on-airplane operation of all emergency evacuation systems (including the
door-opening assist mechanisms and slide or slide raft deployment) on 10
percent of each type of airplane (at least one airplane per type) in their
fleets. NTSB said that these demonstrations should be conducted on an
airplane in a controlled environment so that qualified personnel can
properly evaluate the entire evacuation system. NTSB indicated that the
Appendix VI
Summaries of Potential Improved Evacuation
Safety Advancements
results of the demonstrations (including an explanation of the reasons for
any failures) should be documented for each component of the system and
should be reported to FAA.4
Overwing Exit Doors
Background Prompted by a tragedy in which 57 of the 137 people on board a
British Airtours B-737 were killed because passengers found exit doors
difficult to access and operate, the British Civil Aviation Authority
initiated a research program to explore changes to the design of the
overwing exit (Type III) door.
Trained crewmembers are expected to operate most of the emergency
equipment on an airplane, including most floor-level exit doors. But
overwing exit doors, termed "self-help exits," are expected to be and will
primarily be opened by passengers without formal training.5 NTSB reported
that even when flight attendants are responsible for opening the overwing
exit doors, passengers are likely to make the first attempt to open the
overwing exit hatches because the flight attendants are not physically
located near the overwing exits.
There are now two basic types of overwing exit doors-the "self-help" doors
that are manually removed inward and then stowed and the newer "swing out"
doors that open outward on a hinge.
According to NTSB, passengers continue to have problems removing the
inward-opening exit door and stowing it properly. The manner in which the
overwing exit is opened and how and where the hatch should be stowed is
not intuitively obvious to passengers, nor is it easily or consistently
depicted graphically. NTSB recently recommended to FAA that Type III
overwing exits on newly manufactured aircraft be easy and intuitive to
4NTSB, Emergency Evacuation of Commercial Airplanes, 2001, [A-00-76]
(Washington, D.C.:2000).
5The overwing exit hatch can weigh as much as 65 pounds and be 20 inches
wide and 36 inches high.
Appendix VI
Summaries of Potential Improved Evacuation
Safety Advancements
open and have automatic stowage out of the egress path.6 NTSB has
indicated that the semiautomatic, fast-opening, Type III overwing exit
hatch could give passengers additional evacuation time.
Status Over-wing exit doors that "swing out" on hinges rather than
requiring manual removal are currently available. The European Joint
Aviation Authorities (JAA) has approved the installation of these
outward-opening hinged doors on new-production aircraft in Europe. In
addition, Boeing has redesigned the overwing exit door for its
next-generation 737 series. This redesigned, hinged door has pressurized
springs so that it essentially pops up and outward, out of the way, once
its lever is pulled. The exit door handle was also redesigned and tested
to ensure that anyone could operate the door using either single or double
handgrips. Approximately 200 people who were unfamiliar with the new
design and had never operated an overwing exit tested the outward-opening
exit door. These tests found that the average adult could operate the door
in an emergency. The design eliminates the problem of where to stow the
exit hatch because the door moves up and out of the egress route.
While the new swing-out doors are available, it will take some time for
them to be widely used. Because of structural difficulties and cost, the
new doors are not being considered for the existing fleet. For
new-production airplanes, their use is mixed because JAA requires them in
Europe for some newer Boeing 737s, but FAA does not require them in the
United States. However, FAA will allow their use. As a result, some
airlines are including the new doors on their new aircraft, while others
are not. For example, Southwest Airlines has the new doors on its Boeing
737s. The extent to which other airlines and aircraft models will have the
new doors installed remains to be seen and will likely depend on the cost
of installation, the European market for the aircraft, and any additional
costs to train flight attendants in its use.
6NTSB, Emergency Evacuation of Commercial Airplanes, [A-00-76]
(Washington, D.C., 2000).
Appendix VI
Summaries of Potential Improved Evacuation
Safety Advancements
Next Generation Evacuation Equipment and Procedures
Background Airbus, a leading aircraft manufacturer, has begun building a
family of A380 aircraft, also called Large Transport Aircraft (see fig.
16). Early versions of the A380, which is scheduled to begin flight tests
in 2005 and enter commercial service in 2006, will have 482 to 524 seats.
The A380-800 standard layout references 555 seats. Later larger
configurations could accommodate up to 850 passengers. The A380 is
designed to have 16 emergency doors and require 16 escape slides, compared
with the 747, which requires 12. Later models of the A380 could have 18
emergency exits and escape slides.
Status The advent of this type of Large Transport Aircraft is raising
questions about how passengers will exit the aircraft in an emergency. The
upper deck doorsill of the A380 will be approximately 30 feet above the
ground, depending on the position (attitude) of the aircraft. According to
an Airbus official responsible for exit slide design and operations,
evacuation slides have to reach the ground at a safe angle even if the
aircraft is tipped up; however, extra slide length is undesirable if the
sill height is normal.
Appendix VI
Summaries of Potential Improved Evacuation
Safety Advancements
Previously, regulations would have required slides only to touch the
ground in the tip-up case, even if that meant introduction of relatively
steep sliding surfaces. However, because of the sill height, passengers
may hesitate before jumping and their hesitation may extend the total
evacuation time. Because some passengers may be reluctant to leap onto the
slide when they can see how far it is to the ground, the design concept of
the A380 evacuation slides includes blinder walls at the exit and a curve
in the slide to mask the distance to the ground.
A next-generation evacuation system developed by Airbus and Goodrich
called the "intelligent slide" is a possible solution to the problem of
the Large Transport Aircraft's slide length. The technology is not a part
of the slide, but is connected to the slide through what is called a door
management system composed of sensors. The "brains" of the technology will
be located inside the forward exit door of the cabin, and the technology
is designed to adjust the length of the slide according to the fuselage's
tipping angle to the ground. The longest upper-deck slide for an A380
could exceed 50 feet.
The A380 slides are made of a nylon-based fabric that is coated with
urethane or neoprene, and they are 10 percent lighter than most other
slides on the market. They have to be packed tightly into small bundles at
the foot of emergency exit doors and are required to be fully inflated in
6 seconds. Officials at Airbus noted that the slides are designed to
withstand the radiant heat of a postimpact fire for 180 seconds, compared
with the 90 seconds required by regulators.
According to a Goodrich official, FAA will require Goodrich to conduct
between 2,000 and 2,500 tests on the A380 slides to make sure they can
accommodate a large number of passengers quickly and withstand wind, rain,
and other weather conditions. The upper-level slides, which are wide
enough for two people, have to enable the evacuation of 140 people per
minute, according to Airbus officials. An issue to be resolved is whether
a full-scale demonstration test will be required or whether a partial test
using a certain number of passengers, supplemented by a computer
simulation of an evacuation of 555 passengers, can effectively demonstrate
an evacuation from this type of aircraft. Airbus officials told us that a
full-scale demonstration could result in undesirable injuries to the
participants and is therefore not the preferred choice.
Officials at the Association of Flight Attendants have expressed concern
that there has not been a full-scale evacuation demonstration involving
the
Appendix VI
Summaries of Potential Improved Evacuation
Safety Advancements
A380. They are concerned that computer modeling might not really match the
human experience of jumping onto a slide from that height. In addition,
they are concerned that other systems involved in emergency exiting, such
as the communication systems, need to be tested under controlled
conditions. As a result, they believe a full-scale demonstration under the
current 90-second standard is necessary.
Personal Flotation Devices
Background All commercial aircraft that fly over water more than 50
nautical miles from the nearest shore are required to be equipped with
flotation devices for each occupant of the airplane. According to FAA, 44
of the 50 busiest U.S. airports are located within 5 miles of a
significant body of water. In addition, life vests, seat cushions, life
rafts, and exit slides may be used as flotation devices for water
emergencies.
FAA policies dictate that if personal flotation devices are installed
beneath the passenger seats of an aircraft, the devices must be easily
retrievable. Determinations of compliance with this requirement are based
on the judgment of FAA as the certifying authority.
Status FAA is conducting research and testing on the location and types of
flotation devices used in aircraft. When it has completed this work, it is
likely to provide additional guidance to ensure that the devices are
easily retrievable and usable. FAA's research is designed to analyze human
performance factors, such as how much time passengers need to retrieve
their vests, whether and how the cabin environment physically interferes
with their efforts, and how physically capable passengers are of reaching
their vests while seated and belted. FAA is reviewing four different life
vest installation methods and has conducted tests on 137 human subjects.
According to an early analysis of the data, certain physical installation
features significantly affect both the ability of a typical passenger to
retrieve an underseat life vest and the ease of retrieval. This work may
lead to additonal guidance on the location of personal flotation devices.
Appendix VI
Summaries of Potential Improved Evacuation
Safety Advancements
FAA's research may also indicate a need for additional guidance on the use
of personal flotation devices. In a 1998 report on ditching aircraft and
water survival, FAA found that airlines differed in their instructions to
passengers on how to use personal flotation devices.7 For example, some
airlines advise that passengers hold the cushions in front of their
bodies, rest their chins on the cushions, wrap their arms around the
cushions with their hands grasping the outside loops, and float vertically
in the water. Other airlines suggest that passengers lie forward on the
cushions, grasp and hold the loops beneath them, and float horizontally.
FAA also reported that airlines' flight attendant training programs
differed in their instructions on how to don life vests and when to
inflate them.
7LB & M Associates, Inc., and Garnet A. McLean, Analysis of Ditching and
Water Survival Training Programs of Major Airframe Manufacturers and
Airlines, CAMI [DOT/FAA/AM-98/19], (Washington, D.C.).
Appendix VII
Summaries of General Cabin Occupant Safety and Health Advancements
This appendix presents information on the background and status of
potential advancements in general cabin occupant safety and health that we
identified, including the following:
o advanced warnings of turbulence;
o preparations for in-flight medical emergencies;
o reductions in health risks to passengers with certain medical
conditions, including deep vein thrombosis; and
o improved awareness of radiation exposure.
This appendix also discusses occupational safety and health standards for
the flight attendant workforce.
Advanced Warnings of Turbulence
Background According to FAA, the leading cause of in-flight injuries for
cabin occupants is turbulence. In June 1995, following two serious events
involving turbulence, FAA issued a public advisory to airlines urging the
use of seat belts at all times when passengers are seated, but concluded
that the existing rules did not require strengthening. In May 2000, FAA
instituted a public awareness campaign, called Turbulence Happens, to
stress the importance of wearing safety belts to the flying public.
Because of the potential for injury from unexpected turbulence, ongoing
research is attempting to find ways to better identify areas of turbulence
so that pilots can take corrective action to avoid it. In addition, FAA's
July 2003 draft strategic plan targets a 33 percent reduction in the
number of turbulence injuries to cabin occupants by 2008-from an annual
average of 15 injuries per year for fiscal years 2000 through 2002 to no
more than 10 injuries per year.
Status FAA is currently evaluating new airborne weather radar and other
technologies to improve the timeliness of warnings to passengers and
flight
Appendix VII
Summaries of General Cabin OccupantSafety
and Health Advancements
attendants about impending turbulence. For example, the Turbulence Product
Development Team, within FAA's Aviation Weather Research Program, has
developed a system to measure turbulence and downlink the information in
real time from commercial air carriers. The International Civil Aviation
Organization has approved this system as an international standard.
Ongoing research includes (1) detecting turbulence in flight and reporting
its intensity to augment pilots' reports, (2) detecting turbulence
remotely from the ground or in the air using radar, (3) detecting
turbulence remotely using LIDAR1 or the Global Positioning System's
constellation of satellites, and (4) forecasting the likelihood of
turbulence over the continental United States during the next 12 hours.
Prototypes of the in-flight detection system have been installed on 100
737-300s operated by United Airlines, and two other domestic air carriers
have expressed an interest in using the prototype. FAA also plans to
improve (1) training on standard operating procedures to reduce injuries
from turbulence, (2) the dissemination of pilots' reports of turbulence,
and (3) the timeliness of weather forecasts to identify turbulent areas.
Furthermore, FAA encourages and some airlines require passengers to keep
their seatbelts fastened when seated to help avoid injuries from
unexpected turbulence.
Currently, pilots rely primarily on other pilots to report when and where
(e.g., specific altitudes and routes) they have encountered turbulent
conditions en route to their destinations; however, these reports do not
accurately identify the location, time, and intensity of the turbulence.
Further research and testing will be required to develop technology to
accurately identify turbulence and to make the technology affordable to
the airlines, which would ultimately bear the cost of upgrading their
aircraft fleets.
Preparations for In-flight Medical Emergencies
1LIDAR (LIght Detection And Ranging) is a technology that can measure the
distance, speed, rotation, and chemical composition and concentration of a
remote target, such as turbulence.
Appendix VII
Summaries of General Cabin OccupantSafety
and Health Advancements
Background The Aviation Medical Assistance Act of 1998 directed FAA to
determine whether the current minimum requirements for air carriers'
emergency medical equipment and crewmember emergency medical training
should be modified. In accordance with the act, FAA collected data for a
year on in-flight deaths and near deaths and concluded that enhancements
to medical kits and a requirement for airlines to carry automatic external
defibrillators were warranted. Specifically, the agency found that these
improvements would allow cabin crewmembers to deal with a broader range of
in-flight emergencies.
Status On April 12, 2001, FAA issued a final rule requiring air carriers
to equip their aircraft with enhanced emergency medical kits and automatic
external defibrillators by May 12, 2004. Most U.S. airlines have installed
this equipment in advance of the deadline.
In the future, new larger aircraft may require additional improvements to
meet passengers' medical needs. For example, new large transport aircraft,
such as the Airbus A-380, will have the capacity to carry about 555 people
on long-distance flights. Some aviation safety experts are concerned that
with the large number of passengers on these aircraft, the number of
in-flight medical emergencies will increase and additional precautions for
in-flight medical emergencies (e.g., dedicating an area for passengers who
experience medical emergencies in flight) should be considered. Airbus has
proposed a medical room in the cabin of its A-380 as an option for its
customers.
Reducing Health Risks to Passengers with Certain Medical Conditions
Background Passengers with certain medical conditions (e.g., heart and
lung diseases) can be at higher risk of health-related complications from
air travel than the general population. For example, passengers who have
limited heart or lung function or have recently had surgery or a leg
injury can be at greater risk of developing a condition known as deep vein
thrombosis (DVT) or
Appendix VII
Summaries of General Cabin OccupantSafety
and Health Advancements
travelers' thrombosis, in which blood clots can develop in the deep veins
of the legs from extended periods of inactivity. Air travel has not been
linked definitively to the development of DVT, but remaining seated for
extended periods of time, whether in one's home or on a long-distance
flight, can cause blood to pool in the legs and increase the chances of
developing DVT. In a small percentage of cases, the clots can break free
and travel to the lungs, with fatal results.
In addition, the reduced levels of oxygen available to passengers
in-flight can have detrimental health effects on passengers with heart,
circulatory, and respiratory disorders because lower levels of oxygen in
the air produce lower levels of oxygen in the body-a condition known as
hypoxia. Furthermore, changes in cabin pressure (primarily when the
aircraft ascends and descends) can negatively affect ear, nose, and throat
conditions and pose problems for those flying after certain types of
surgery (e.g., abdominal, cardiac, and eye surgery).
Status Information on the potential effects of air travel on passengers
with certain medical conditions is available; however, additional
research, such as on the potential relationship between DVT and air
travel, is ongoing. The National Research Council, in a 2001 report on
airliner cabin air quality, recommended, among other things, that FAA
increase efforts to provide information on health issues related to air
travel to crewmembers, passengers, and health professionals. According to
FAA's Federal Air Surgeon, since this recommendation was received, the
agency has redoubled its efforts to make information and recommendations
on air travel and medical issues available through its Web site
www.cami.jccbi.gov/aam-400/PassengerHandS.htm. This site also includes
links to the Web sites of other organizations with safety and health
information for air travelers, such as the Aerospace Medical Association,
the American Family Physician (Medical Advice for Commercial Air
Travelers), and the Sinus Care Center (Ears, Altitude, and Airplane
Travel), and videos on safety and health issues for pilots and air
travelers. The Aerospace Medical Association's Web site,
http://www.asma.org/publication.html, includes guidance for physicians to
use in advising passengers about the potential risks of flying based on
their medical conditions, as well as information for passengers to use in
determining whether air travel is advisable given their medical
conditions. Furthermore, some airlines currently encourage passengers to
do exercises while seated, to get up and walk around during long flights,
or to do both to improve blood circulation; however, walking around the
airplane can also
Appendix VII
Summaries of General Cabin OccupantSafety
and Health Advancements
put passengers at risk of injuries from unexpected turbulence. In
addition, a prototype of a seat has been designed with imbedded sensors,
which record the movement of a passenger and send this information to the
cabin crew for monitoring. The crew would then be able to track passengers
seated for a long time and could suggest that these passengers exercise in
their seats or walk in the cabin aisles to enhance circulation.
While FAA's Web site on passenger and pilot safety and health provides
links to related Web sites and videos (e.g., cabin occupant safety and
health issues), historically, the agency has not tracked who uses its Web
site or how frequently it is used to monitor the traveling public's
awareness and use of this site. Agency officials told us that they plan to
install a counter capability on its Civil Aerospace Medical Institute Web
site by the end of August 2003 to track the number of visits to its
aircrew and passenger health and safety Web site. The World Health
Organization has initiated a study to help determine if a linkage exists
between DVT and air travel. Further, FAA developed a brochure on DVT that
has been distributed to aviation medical examiners and cited in the
Federal Air Surgeon's Bulletin. The brochure is aimed at passengers rather
than airlines and suggests exercises that can be done to promote
circulation.
Improved Awareness of Radiation Exposure
Background Pilots, flight attendants, and passengers who fly frequently
are exposed to cosmic radiation at higher levels (on a cumulative basis)
than the average airline passenger and the general public living at or
near sea level. This is because they routinely fly at high altitudes,
which places them closer to outer space, which is the primary source of
this radiation. High levels of radiation have been linked to an increased
risk of cancer and potential harm to fetuses. The amount of radiation that
flight attendants and frequent fliers are exposed to-referred to as the
dose-depends on four primary factors: (1) the amount of time spent in
flight; (2) the latitude of the flight- exposure increases at higher
latitudes; for example, at the same altitude, radiation levels at the
poles are about twice those at the equator; (3) the altitude of the
flight-exposure is greater at high altitudes because the layer of
protective atmosphere becomes thinner; and (4) solar activity- exposure is
higher when solar activity increases, as it does every 11 years or so.
Peak periods of solar activity, which can increase exposure to
Appendix VII
Summaries of General Cabin OccupantSafety
and Health Advancements
radiation by 10 to 20 times, are sometimes called solar storms or solar
flares.
Status FAA's Web site currently makes available guidance on radiation
exposure levels and risks for flight and cabin crewmembers, as well as a
system for calculating radiation doses from flying specific routes and
specific altitudes. To increase crewmembers' awareness of in-flight
radiation exposure, FAA issued two Advisory Circulars for crewmembers. The
first Advisory Circular, issued in 1990, provided information on (1)
cosmic radiation and air shipments of radioactive material as sources of
radiation exposure during air travel; (2) guidelines for exposure to
radiation; (3) estimates of the amounts of radiation received on air
carriers' flights on various routes to and from, or within, the contiguous
United States; and (4) examples of calculations for estimating health
risks from exposure to radiation. The second Advisory Circular, issued in
1994, recommended training for crewmembers to inform them about in-flight
radiation exposure and known associated health risks and to assist them in
making informed decisions about their work on commercial air carriers. The
circular provided a possible outline of courses, but left it to air
carriers to gather the subject matter materials. To facilitate the
monitoring of radiation exposure levels by airliner crewmembers and the
public (e.g., frequent fliers), FAA has developed a computer model, which
is publicly available via the agency's Web site. This Web site also
provides guidance and recommendations on limiting radiation exposure.
However, it is unclear to what extent flight attendants, flight crews, and
frequent fliers are aware of and use FAA's Web site to track the radiation
exposure levels they accrue from flying. Agency officials told us that
they plan to install a counter capability its Civil Aerospace Medical
Institute Web site by the end of August 2003, to track the number of
visits to its aircrew and passenger health and safety Web site. FAA also
plans to issue an Advisory Circular by early next year, which incorporates
the findings of a just completed FAA report, "What Aircrews Should Know
About Their Occupational Exposure to Ionizing Radiation." This Advisory
Circular will include recommended actions for aircrew and information on
solar flare event notification of aircrew. While FAA provides guidance and
recommendations on limiting the levels of cosmic radiation that flight
attendants and pilots are exposed to, it has not developed any
regulations.
In contrast, the European Union issued a directive for workers in May
1996, including air carrier crewmembers (cabin and flight crews) and the
general public, on basic safety and health protections against dangers
arising from
Appendix VII
Summaries of General Cabin OccupantSafety
and Health Advancements
ionizing radiation. This directive set dose limits and required air
carriers to (1) assess and monitor the exposure of all crewmembers to
avoid exceeding exposure limits, (2) work with those individuals at risk
of high exposure levels to adjust their work or flight schedules to reduce
those levels, and (3) inform crewmembers of the health risks that their
work involves from exposure to radiation. It also required airlines to
work with female crewmembers, when they announce a pregnancy, to avoid
exposing the fetus to harmful levels of radiation. This directive was
binding for all European Union member states and became effective in May
2000. According to European safety officials, pregnant crewmembers are
often given the option of an alternative job with the airline on the
ground to avoid radiation exposure to their fetuses. Furthermore, when
flight attendants and pilots reach recommended exposure limits, European
air carriers work with crewmembers to limits or change their subsequent
flights and destinations to minimize exposure levels for the balance of
the year. Some air carriers ground crewmembers when they reach annual
exposure limits or change their subsequent flights and destinations to
minimize exposure levels for the balance of the year.
Occupational Safety and Health Standards for Flight Attendants
Background In 1975, FAA assumed responsibility from the Occupational
Health and Safety Administration (OSHA) for establishing safety and health
standards for flight attendants. However, FAA has only recently begun to
take action to provide this workforce with OSHA-like protections. For
example, in August 2000, FAA and OSHA entered into a memorandum of
understanding and issued a joint report in December 2000, which identified
safety and health concerns for the flight attendant workforce and the
extent to which OSHA-type standards could be used without compromising
aviation safety. On September 29, 2001, the DOT Office of the Inspector
General (DOT IG) reported that FAA had made little progress toward
providing flight attendants with workplace protections and urged FAA to
address the recommendations in the December 2000 report and move forward
with setting safety and health standards for the flight attendant
workforce. In April 2002, the DOT IG reported that FAA and OSHA had made
no progress since it issued its report in September 2001. According to FAA
officials, the
Appendix VII
Summaries of General Cabin OccupantSafety
and Health Advancements
joint FAA and OSHA effort was put on hold because of other priorities that
arose in response to the events of September 11, 2001.
Status FAA has not yet established occupational safety and health
standards to protect the flight attendant workforce. FAA is conducting
research and collecting data on flight attendants' injuries and illnesses.
On March 4, 2003, FAA announced the creation of a voluntary program for
air carriers, called the Aviation Safety and Health Partnership Program.
Through this program, the agency intends to enter into partnership
agreements with participating air carriers, which will, at a minimum, make
data on their employees' injuries and illnesses available to FAA for
collection and analysis. FAA will then establish an Aviation Safety and
Health Program Aviation Rule-Making Committee to provide advice and
recommendations to
o develop the scope and core elements of the partnership program
agreement;
o review and analyze the data on employees' injuries and illnesses;
o identify the scope and extent of systematic trends in employees'
injuries and illnesses;
o recommend remedies to FAA that use all current FAA protocols, including
rule-making activities if warranted, to abate hazards to employees; and
o create any other advisory and oversight functions that FAA deems
necessary.
FAA plans to select members to provide a balance of viewpoints, interests,
and expertise. The program preserves FAA's complete and exclusive
responsibility for determining whether proposed abatements of safety and
health hazards would compromise or negatively affect aviation safety.
FAA is also funding research through the National Institute for
Occupational Safety and Health (NIOSH) to, among other things, determine
the effects of flying on the reproductive health of flight attendants,
much of
Appendix VII
Summaries of General Cabin OccupantSafety
and Health Advancements
which has been completed.2 FAA plans to monitor cabin air quality on a
selected number of flights, which will help it set standards for the
flight attendant workforce.
The Association of Flight Attendants has collected a large body of data on
flight attendants' injuries and illnesses, which it considers sufficient
for use in establishing safety and health standards for its workforce.
Officials from the association do not believe that FAA needs to collect
additional data before starting the standard-setting process.
The European Union has occupational safety and health standards in place
to protect flight attendants, including standards for monitoring their
levels of radiation exposure. An official from an international
association of flight attendants told us that while flight attendants in
Europe have concerns similar to those of flight attendants in the United
States (e.g., concerns about air quality in airliner cabins), the European
Union places a heavier emphasis on worker safety and health, including
safety and health protections for flight attendants.
2NIOSH is also conducting research on airliner cabin environmental
quality, respiratory symptoms of flight attendants, and disease
transmission.
Appendix VIII
Application of a Cost Analysis Methodology to Inflatable Lap Belts
The following illustrates how a cost analysis might be conducted on each
of the potential advancements discussed in this report. Costs estimated
through this analysis could then be weighed against the potential lives
saved and injuries avoided from implementing the advancements. This
methodology would allow advancements to be compared using comparable cost
data that when combined with similar analyses of effectiveness to help
decisionmakers determine which advancements would be most effective in
saving lives and avoiding injuries, taking into account their costs. The
methodology provides for developing a cost estimate despite significant
uncertainties by making use of historical data (e.g, historical variations
in fuel prices) and best engineering judgments (e.g., how much weight an
advancement will add and how much it will cost to install, operate, and
maintain). The methodology formally takes into account the major sources
of uncertainty and from that information develops a range of cost
estimates, including a most likely cost estimate. Through a common
approach for analyzing costs, the methodology facilitates the development
of comparable estimates. This methodology can be applied to advancements
in various stages of development.
Inflatable Lap Belts Inflatable lap belts are designed to protect
passengers from a fatal impact with the interior of the airplane, the most
common cause of death in survivable accidents. Inflatable seat belts adapt
advanced automobile technology to airplane seats in the form of seat belts
with air bags embedded in them. Several hundred of these seatbelt airbags
have been installed in commercial airliners in bulkhead rows.
Summary of Results We calculated that requiring these belts on an
average-sized airplane in the U.S. passenger fleet would be likely to cost
from $98,000 to $198,000 and to average about $140,000 over the life of
the airplane. On an annual basis, the cost would be likely to range from
$8,000 to $17,000 and to average $12,000.
We considered several factors to explain this range of possible costs. The
installation price of these belts is subject to uncertainty because of
their limited production to date. In addition, these belts add weight to
an aircraft, resulting in additional fuel costs. Fuel costs depend on the
price of jet fuel and on how many hours the average airplane operates,
both subject to uncertainty. Table 5 lists the results of our cost
analysis for an average-sized airplane in the U.S. fleet.
Appendix VIII
Application of a Cost Analysis Methodology
to Inflatable Lap Belts
Table 4: Costs to Equip an Average-sized Airplane in the U.S. Fleet with
Inflatable Lap Seat Belts, Estimated under Alternative Scenarios (In 2002
discounted dollars) Cost scenario
Cost Low Average High 95 percentilea
Life-cycle $98,000 $140,000 $198,000 $186,000
Annualized $8,000 $12,000 $17,000 $16,000
Per ticketb $0.08 $0.13 $0.19 $0.18
Source: GAO analysis.
aFor example, a 95 percentile estimate means that there is a 95 percent
probability that the total life-cycle costs per airplane will be $186,000
or less.
bCost rounded to the nearest cent.
According to our analysis, the life-cycle and annualized cost estimates in
table 5 are influenced most by variations in jet fuel prices, followed by
the average number of hours flown per year and the installation price of
the belts. The cost per ticket is influenced most by variations in jet
fuel prices, followed by the average number of hours flown per year, the
number of aircraft in the U.S. fleet, and the number of passenger tickets
issued.
Methodology To analyze the cost of inflatable lap belts, we collected data
on key cost variables from a variety of sources. Information on the belts'
installation price, annual maintenance and refurbishment costs, and added
weight was obtained from belt manufacturers. Historical information on jet
fuel prices, extra gallons of jet fuel consumed by a heavier airplane,
average hours flown per year, average number of seats per airplane, number
of airplanes in the U.S. fleet, and number of passenger tickets issued per
year was obtained from FAA and DOT's Office of Aviation Statistics.
To account for variation in the values of these cost variables, we
performed a Monte Carlo simulation.1 In this simulation, values were
randomly drawn 10,000 times from probability distributions characterizing
possible values
1"Monte Carlo simulation is a widely used computational method for
generating probability distributions of variables that depend on other
variables or parameters represented as probability distributions. Monte
Carlo methods are to be contrasted with the deterministic methods used to
generate specific single number or point estimates." Susan Poulter, "Monte
Carlo Simulation in Environmental Risk Assessment - Science, Policy And
Legal Issues," 9 Risk: Health, Safety & Environment 7 [Winter 1998].
Appendix VIII
Application of a Cost Analysis Methodology
to Inflatable Lap Belts
for the number of seat belts per airplane, seat belt installation price,
jet fuel price, number of passenger tickets, number of airplanes, and
hours flown.2 This simulation resulted in forecasts of the life-cycle cost
per airplane, the annualized cost per airplane, and the cost per ticket.
Major assumptions in the cost analysis are described by probability
distributions selected for these cost variables. For jet fuel prices,
average number of hours flown per year, and average number of seats per
airplane, historical data were matched against possible probability
distributions.3 Mathematical tests were performed to find the best fit
between each probability distribution and the data set's distribution. For
the installation price, number of passenger tickets, and number of
airplanes, less information was available.4 For these variables, we
selected probability distributions that are widely used by researchers.
Table 6 lists the type of probability distribution and the relevant
parameters of each distribution for the cost variables.
Table 5: Key Assumptions
Type of Mean or Standard
Cost distribution average deviation Minimum Maximum Likeliest Mode Scale
variable
Fuel price lognormal $0.93 $0.33
Seats lognormal 161 8
Installation triangular $300 $600 $450
price
Hours extreme 2,353 2,643 539
value
Airplanes normal 4,438 399
Tickets normal 419 35
Source: GAO analysis.
2A probability distribution is a set of all possible events and their
associated probabilities. Probability refers to the likelihood of an
event.
3Historical data from 1975 through 2001 were available for the number of
seats per plane, and from 1977 through 2002 for jet fuel prices. Aircraft
utilization data for 2001 were available for annual hours per aircraft.
4Historical data from 1995 through 2001 were available for the number of
planes and tickets.
Appendix IX
GAO Contacts and Staff Acknowledgments
GAO Contacts Gerald L. Dillingham (202) 512-2834 Glen Trochelman (202)
512-2834 Beverly Norwood (202) 512-2834
Staff In addition to those named above, Chuck Bausell, Helen Chung,
Elizabeth Eisenstadt, David Ehrlich, Bert Japikse, Sarah Lynch, Sara Ann
Acknowledgments Moessbauer, and Anthony Patterson made key contributions
to this report.
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