[Federal Register Volume 74, Number 157 (Monday, August 17, 2009)]
[Proposed Rules]
[Pages 41522-41556]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E9-19350]
[[Page 41521]]
-----------------------------------------------------------------------
Part III
Department of Transportation
-----------------------------------------------------------------------
Federal Aviation Administration
-----------------------------------------------------------------------
14 CFR Parts 1 and 23
Certification of Turbojets; Proposed Rule
Federal Register / Vol. 74, No. 157 / Monday, August 17, 2009 /
Proposed Rules
[[Page 41522]]
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Parts 1 and 23
[Docket No. FAA-2009-0738; Notice No. 09-09]
RIN 2120-AJ22
Certification of Turbojets
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
-----------------------------------------------------------------------
SUMMARY: This action proposes to enhance safety by amending the
applicable standards for part 23 turbojet-powered airplanes--which are
commonly referred to as ``turbojets''--to reflect the current needs of
industry, accommodate future trends, address emerging technologies, and
provide for future airplane operations. This action is necessary to
eliminate the current workload of processing exemptions, special
conditions, and equivalent levels of safety findings necessary to
certificate light part 23 turbojets. The intended effect of the
proposed changes would: Standardize and simplify the certification of
part 23 turbojets; clarify areas of frequent non-standardization and
misinterpretation, particularly for electronic equipment and system
certification; and codify existing certification requirements in
special conditions for new turbojets that incorporate new technologies.
DATES: Send your comments on or before November 16, 2009.
ADDRESSES: You may send comments identified by Docket Number FAA-2009-
0738 using any of the following methods:
Federal eRulemaking Portal: Go to http://www.regulations.gov and follow the online instructions for sending your
comments electronically.
Mail: Send comments to Docket Operations, M-30, U.S.
Department of Transportation, 1200 New Jersey Avenue, SE., Room W12-
140, West Building Ground Floor, Washington, DC 20590-0001.
Hand Delivery or Courier: Bring comments to Docket
Operations in Room W12-140 of the West Building Ground Floor at 1200
New Jersey Avenue, SE., Washington, DC, between 9 a.m. and 5 p.m.,
Monday through Friday, except Federal holidays.
Fax: Fax comments to Docket Operations at 202-493-2251.
For more information on the rulemaking process, see the SUPPLEMENTARY
INFORMATION section of this document.
Privacy: We will post all comments we receive, without change, to
http://www.regulations.gov, including any personal information you
provide. Using the search function of our docket Web site, anyone can
find and read the electronic form of all comments received into any of
our dockets, including the name of the individual sending the comment
(or signing the comment for an association, business, labor union,
etc.). You may review DOT's complete Privacy Act Statement in the
Federal Register published on April 11, 2000 (65 FR 19477-78) or you
may visit http://DocketsInfo.dot.gov.
Docket: To read background documents or comments received, go to
http://www.regulations.gov at any time and follow the online
instructions for accessing the docket. Or, go to Docket Operations in
Room W12-140 of the West Building Ground Floor at 1200 New Jersey
Avenue, SE., Washington, DC, between 9 a.m. and 5 p.m., Monday through
Friday, except Federal holidays.
FOR FURTHER INFORMATION CONTACT: For technical questions concerning
this proposed rule, contact Pat Mullen, Regulations and Policy, ACE-
111, Federal Aviation Administration, 901 Locust St., Kansas City, MO
64106; telephone: (816) 329-4111; facsimile (816) 329-4090; e-mail:
[email protected]. For legal questions concerning this proposed rule,
contact Mary Ellen Loftus, ACE-7, Federal Aviation Administration, 901
Locust St., Kansas City, MO 64106; telephone: (816) 329-3764; e-mail:
[email protected].
SUPPLEMENTARY INFORMATION: Later in this preamble under the Additional
Information section, we discuss how you can comment on this proposal
and how we will handle your comments. Included in this discussion is
related information about the docket, privacy, and the handling of
proprietary or confidential business information. We also discuss how
you can get a copy of this proposal and related rulemaking documents.
Authority for This Rulemaking
The FAA's authority to issue rules on aviation safety is found in
Title 49 of the United States Code. Subtitle I, Section 106 describes
the authority of the FAA Administrator. Subtitle VII, Aviation Programs
describes in more detail the scope of the agency's authority.
This rulemaking is promulgated under the authority described in
Subtitle VII, Part A, Subpart III, Section 44701. Under that section,
the FAA is charged with promoting safe flight of civil airplanes in air
commerce by prescribing minimum standards required in the interest of
safety for the design and performance of airplanes. This regulation is
within the scope of that authority because it prescribes new safety
standards for the design of normal, utility, acrobatic, and commuter
category airplanes.
Table of Contents
I. Background
A. Historical Certification Requirements Overview
B. Aviation Rulemaking Committee (ARC) Recommendations
C. Proposed Regulatory Requirements Overview
II. Discussion of the Proposed Regulatory Requirements
III. Regulatory Notices and Analyses
IV. The Proposed Amendments
I. Background
A. Historical Certification Requirements Overview
Title 14 Code of Federal Regulations (14 CFR) part 23 provides the
airworthiness standards for Normal, Utility, Acrobatic, and Commuter
Category Airplanes. The first application for the certification of a
turbojet airplane under part 23 occurred in the 1970s before many of
the current turbine requirements were added to part 23. Prior to this,
turbojet powered airplanes were certificated to the standards under
part 25. Part 25 provides the airworthiness standards for Transport
category airplanes. A turbojet is a jet engine that develops thrust
using a turbine compressor which is propelled by high speed exhaust
gases expelled as a jet. The FAA implemented many of the certification
requirements for early part 23 turbojets through special conditions
based on 14 CFR part 25 (pre-amendment 25-42, (43 FR 2320))
requirements. Almost all special conditions applied to turbojets were
for part 23, subpart B, Flight, and subpart G, Operating Limitations
and Information.
Special conditions for part 23 certification increased performance
requirements for emerging turbojets similar to those covered by early
part 25 standards. The FAA established these special conditions to
ensure a minimum one-engine inoperative (OEI) performance level that
would be included in the airplane's limitations, thereby guaranteeing
single-engine climb performance. The level of safety provided by the
special conditions was purposely higher for the early turbojets than
for propeller-driven airplanes in the same weight band because the
manufacturers and the FAA wanted part 23 turbojets to be similar to
part 25
[[Page 41523]]
business jets. Special conditions also addressed the following safety
concerns: (1) The lack of turbine requirements in part 23, (2) the
sensitivity of turbine engines to altitude and temperature effects, and
(3) the high takeoff and landing speeds associated with turbojets that
typically required long takeoff and landing distances, as compared to
the performance of reciprocating, multiengine airplanes of that era.
In the mid-1990s, the FAA hosted a meeting for flight test pilot
representatives from the Aircraft Certification Offices. The purpose of
that meeting was to discuss how emerging 600 to 1,200 pound thrust
engines were being developed and how the FAA would certificate future
turbojet programs. The participants considered the prospect for small
single- and multi-engine turbojets. At that time, the FAA assumed that
any new part 23 turbojet would have similar characteristics to any
existing small part 25 turbojet. However, using the preliminary design
estimates from several new turbojets, FAA flight test personnel
realized these assumptions were outdated. Therefore, the FAA needed to
reevaluate its certification standards for turbojets against existing
light-weight airplanes.
The meeting participants did not want to discourage development of
small part 23 turbojets by applying significantly higher standards than
for an equivalent propeller airplane. Therefore, the participants
decided the best approach for future turbojet certification programs
was to apply the existing part 23 weight differentiator of 6,000 pounds
in establishing requirements.
B. Aviation Rulemaking Committee (ARC) Recommendations
On February 3, 2003, we published a notice announcing the creation
of the part 125/135 Aviation Rulemaking Committee.\1\ Part 125
addresses the certification and operations of airplanes having a
seating capacity of 20 or more passengers or a maximum payload capacity
of 6,000 pounds or more. Part 135 addresses the operating requirements
for commuter and on-demand operations and rules governing persons on
board such aircraft. Since some part 23 airplanes operate under parts
125 or 135, the ARC provided recommendations to the FAA for safety
standards applicable for part 23 turbojet airplanes to reflect the
current industry, industry trends, emerging technologies and operations
under parts 125 and 135, and associated regulations. The ARC also
reviewed the existing part 23 certification requirements and the
accident history of light piston-powered, multiengine airplanes up
through small turbojets used privately and for business. In addition,
the ARC reviewed the special conditions applied to part 23 turbojets.
The ARC completed its work in 2005 and submitted its recommendations to
the FAA. Those documents may be reviewed in the docket for this
proposed rule. The ARC recommended modifying forty-one 14 CFR part 23
sections as a result of its review of these areas.
---------------------------------------------------------------------------
\1\ 68 FR 5488
---------------------------------------------------------------------------
As stated earlier, the FAA's intent is to codify standards
consistent with the level of safety currently required through special
conditions. We compared the special conditions applied to part 23
turbojets, as well as several additional proposed part 23 changes, with
the ARC's recommendations. With few exceptions, the ARC recommendations
validated the FAA's long-held approach to certification of part 23
turbojets.
The ARC did not want to impose commuter category takeoff speeds for
turbojets above 6,000 pounds, nor did the ARC want to impose more
stringent requirements for one-engine inoperative (OEI) climb
performance than those established for similar-sized piston-powered and
turboprop multiengine airplanes. The FAA ultimately accepted thirty-
nine of the forty-one ARC recommendations and developed this proposed
rulemaking in accordance with them. The two recommendations we
disagreed with would have lowered the standards previously applied
through special conditions.
C. Proposed Regulatory Requirements Overview
The FAA currently issues type certificates (TCs) to part 23
turbojets using extensive special conditions, exemptions, and
equivalent levels of safety (ELOS). Until recently, this practice of
using special conditions, exemptions, and ELOS did not represent a
significant workload because there were relatively few part 23 turbojet
programs. However, in the past five years, the number of new part 23
turbojet type certification programs has increased more than 100
percent over the program numbers of the past three decades. The need to
incorporate special conditions, exemptions, and ELOS into part 23 stems
from this rise in the number of new turbojet programs and the expected
growth in the number of future programs. Codifying special conditions
would standardize and clarify the requirements for manufacturers during
the design phase of turbojets. Doing so would prevent instances where
manufacturers design turbojets and later have to demonstrate compliance
with special conditions that may require redesign. Codifying special
conditions, exemptions, and ELOS would also eliminate the
manufacturers' and the FAA's workload associated with processing these
documents and could reduce potential delays to project schedules. Many
of the proposed changes in this notice would codify certification
requirements and practices currently accomplished through use of
special conditions, exemptions, and ELOS.
We propose changes to part 1 definitions to clarify new
requirements proposed for part 23. In addition, we propose changes to
part 23 in the areas of:
Airplane categories to allow commuter category
certification of multiengine turbojets;
Flight requirements, including standards for performance,
stability, stalls, and other flight characteristics;
Structure requirements, including standards for emergency
landing conditions and fatigue evaluation;
Design and construction requirements, including standards
for flutter, takeoff warning system, brakes, personnel and cargo
accommodations, pressurization, and fire protection;
Powerplant requirements, including standards for engines,
powerplant controls and accessories, and powerplant fire protection;
Equipment requirements, including general equipment
standards and standards for instruments installation, electrical
systems and equipment, and oxygen systems; and
Operating limitations and information, including standards
for airspeed limitations, kinds of operation, markings and placards,
and airplane flight manual and approved manual material.
II. Discussion of the Proposed Regulatory Amendments
1. Part 1: Definitions Clarifying Power and Engine Terms
We propose to amend part 1 definitions for ``rated takeoff power,''
``rated takeoff thrust,'' ``turbine engine,'' ``turbojet engine,'' and
``turboprop engine.'' Defining engine-specific terms would clarify the
new requirements proposed for part 23. The need to define some of these
terms was also shown by the following communications between the FAA
and members of industry. These communications were based on the
existing part 1 definitions for ``rated takeoff power'' and ``rated
takeoff thrust'', which limit the use of these
[[Page 41524]]
power and thrust ratings to no more than five minutes for takeoff
operation.
In 1990, the Airline Transport Association (ATA) sent a letter to
the FAA asking the FAA to allow 10-minute OEI takeoff approval. At some
airports (mostly foreign), the climb gradient capability needed to
clear distant obstacles after takeoff requires more time at takeoff
thrust than 5 minutes. Using only 5 minutes of takeoff thrust to clear
distant obstacles limits the maximum allowable airplane takeoff weight.
The availability of takeoff thrust or power for use up to 10 minutes,
granted by some foreign authorities, enabled some foreign operators to
dispatch at an increased gross weight over that allowed for U.S.
operators. U.S. operators asked for equal treatment in similar
circumstances. The FAA has approved these requests when they have been
properly substantiated. This policy would also apply to operators of
part 23 turbojet-powered airplanes in order to achieve a climb gradient
necessary to clear obstacles.
2. Expanding Commuter Category to Include Turbojets
Currently, we limit commuter category airplane requirements to
propeller-driven, multiengine airplanes. The FAA has issued exemptions
to allow turbojets weighing more than 12,500 pounds to be certificated
under part 23. The proposal to change Sec. 23.3 would codify the
current FAA practice of certificating multiengine turbojets weighing up
to and including 19,000 pounds under part 23 in the commuter category.
3. Performance, Flight Characteristics, and Other Design Considerations
a. Performance
We propose to extend the commuter category performance requirements
to multiengine turbojets weighing more than 6,000 pounds. This proposal
codifies requirements that we currently impose by special conditions
for these airplanes. Amendment 23-45 (58 FR 42136) requires all
turbine-powered airplanes weighing 6,000 pounds or less to meet many of
the same performance standards for reciprocating-powered airplanes
weighing more than 6,000 pounds. The FAA has determined that turbojets
should meet a higher level of safety than reciprocating-powered
airplanes in the same weight band. By requiring turbojets over 6,000
pounds to meet the higher commuter category certification requirements,
the FAA would remain consistent in establishing more stringent
requirements for turbojet airplanes than for reciprocating airplanes.
The ARC recommended no changes to performance requirements in
Sec. Sec. 23.51, 23.53, 23.55, 23.57, 23.59 and 23.61. The ARC pointed
out that applying the commuter category takeoff performance
requirements to multiengine turbojets weighing more than 6,000 pounds
would include restrictions that could become a takeoff weight
limitation for operations. The ARC stated that these requirements are
too restrictive for part 91 operations. However, existing multiengine
turbojets weighing more than 6,000 pounds are required to meet these
standards through special conditions, and we have seen negligible
operational impact. We have no rationale or basis to support a reduced
level of safety for part 23 turbojets.
The ARC also reviewed FAA and Flight Safety Foundation accident
studies for engine failure on takeoff. The ARC determined that existing
normal category part 23 turboprops operated under part 135 have an
acceptable safety record when compared to turbojets. Furthermore,
turboprops in the accident studies were not certificated with any of
the commuter category performance requirements for climb gradients.
The ARC believed the safety record of the turboprops had more to do
with the inherent reliability of turbine engines rather than the higher
climb gradient. An ARC member suggested the higher OEI climb gradients
originated in part 25 during the large piston transport airplane engine
era. Back then, the large piston engines were prone to failure on
takeoff or initial climb, and the requirements for OEI climb gradients
were necessary for safety.
The ARC further believed raising the OEI climb performance
requirements for most multiengine airplanes was appropriate. However,
the ARC debated the appropriate OEI climb gradients for turbine-powered
airplanes over 6,000 pounds. Based on the reliability of turbine
engines, the ARC only recommended raising the climb performance to 1
percent. This matched the ARC's recommendation of 1 percent for
turbojets under 6,000 pounds. The ARC's recommendation, however, would
reduce the OEI climb performance that is currently required through
special conditions from 2 to 1 percent for turbojet-powered airplanes
over 6,000 pounds.
Existing multiengine turbojets weighing more than 6,000 pounds are
required through special conditions to meet the commuter category
performance requirements (2 percent climb gradient) for OEI. We propose
to maintain the 2 percent OEI climb gradient currently applied through
special conditions for multiengine turbojets over 6,000 pounds. This
climb gradient requirement is safe and prudent, and it is not
reasonable to reduce the level of safety that already exists with part
23 turbojets.
Although special conditions have required 2 percent OEI climb
gradient for multiengine turbojets over 6,000 pounds, there was no data
to support whether small turbojets under 6,000 pounds could meet the
higher 2 percent climb gradient while maintaining reasonable utility.
If our rule changes to Sec. Sec. 23.63 and 23.67 negatively impacted
their utility (i.e., weight-carrying ability), the rule might give the
piston-powered, multiengine airplanes a distinct market advantage.
Accident studies show that turbojets are generally safer than piston-
powered airplanes. Therefore, we wanted to compromise by proposing a
requirement that would provide an adequate minimum safety standard and
encourage production of more turbojets. One multiengine turbojet in
this weight band has been operated as an air taxi, and the FAA expects
this type of operation to grow. While this particular jet is capable of
higher climb performance, we propose only to increase the OEI climb
performance requirement to 1.2 percent because other jets in this
weight band may not be capable of the higher 2 percent climb
performance. Based on accident data, 1.2 percent provides an adequate
minimum safety standard.
Historically, piston-powered, multiengine airplanes were allowed a
lower climb requirement because they would not have any weight-carrying
utility if forced to meet the same requirements of the larger
airplanes. We are continuing this philosophy in this proposal. (See
summary in the table below.)
[[Page 41525]]
Table 1--One-Engine Inoperative Climb Requirements to 400 Feet Above Ground Level (AGL)
----------------------------------------------------------------------------------------------------------------
ARC
Multiengine type/airplane weight band Current rule recommendation FAA proposal
(percent) (percent)
----------------------------------------------------------------------------------------------------------------
Pistons >6,000 lbs....................... Measurably positive.............. 1.0 1.0
Turboprops <=6,000 lbs................... Measurably positive.............. 1.0 1.0
Turboprops >6,000 lbs.................... Measurably positive.............. 1.0 1.0
Turbojets <=6,000 lbs.................... Measurably positive.............. 1.0 1.2
Turbojets >6,000 lbs..................... 2.0 percent imposed through 1.0 2.0
special conditions.
----------------------------------------------------------------------------------------------------------------
In addition to the proposed changes in takeoff and climb
performance requirements described above, we also propose changes to
other performance rules. Currently, part 23 reflects the traditional
small airplane definition of landing configuration stall speed
(VSO). However, certification personnel have interpreted
VSO in part 23 as being the same as that in part 25. This
interpretation has resulted in an unnecessary burden to the applicant.
We are revising the part 23 requirement so that it is distinct from the
part 25 requirement and to retain the original definition of the term.
We are proposing to revise paragraphs (a) and (c) of Sec. 23.49 to
clarify the section. We are also proposing to correct the title of this
section in the CFR to ``Stalling speed'' instead of ``Stalling
period.''
VSO, by definition, is the stall speed in the maximum
landing flap configuration and is not applicable to other flap
configurations. (V speeds are defined in part 1. To simplify the
understanding of the proposed rule, we are adding this information
here.) Current Sec. 23.73 references VSO. The reference to
VSO in this paragraph is an error and should be changed to
reference the stall speed for a specified flap configuration
(VS1). The reference landing approach speed
(VREF) should be based on 1.3 times the VS1. We
propose to amend the standards to address airplanes certificated under
part 23 that may have more than one landing flap setting. We also
propose to apply the commuter category requirements for VREF
to multiengine turbojets over 6,000 pounds maximum weight. In addition,
we propose to apply the commuter category requirements for balked
landings in Sec. 23.77 to all multiengine turbine-powered airplanes
over 6,000 pounds, consistent with current special conditions for
multiengine turbojets and turbine-powered airplanes over 6,000 pounds.
b. Flight Characteristics
The FAA proposes to define ``maximum allowable speed'' and to
clarify the specific speed limitations, which include specific criteria
for VFC, VLE, or VFC/MFC as
appropriate. The proposal for Sec. 23.177 would codify special
conditions that include specific speed limitations. Furthermore, we are
adding a new paragraph to Sec. 23.175(b) to define the VFC/
MFC (maximum speed for stability characteristics) term in
part 23. This definition was inadvertently omitted in the last revision
to part 23.
The FAA proposes to amend the combined lateral-directional dynamic
stability damping requirements for airplanes that operate above 18,000
feet. The existing stability damping requirements, which apply at all
certificated altitudes, were developed when small airplanes typically
operated under 18,000 feet and were not equipped with yaw dampers. The
existing requirement remains appropriate for low altitude operations,
such as for approaches, but it is not appropriate for larger airplanes
that typically use yaw dampers and fly at altitudes well above 18,000
feet. The FAA has issued exemptions for most turbojets certificated
under part 23 because it is appropriate for high-altitude, high-speed
operations. The proposed changes to Sec. 23.181 would reduce the
stability damping requirement at 18,000 feet and above. If adopted,
this amendment would reduce the number of exemptions processed by the
FAA by codifying what is allowed as an acceptable means of compliance.
The FAA proposes to amend the existing stall requirements in
Sec. Sec. 23.201 and 23.203 to include language from the turbojet
special conditions. We propose clarifying the requirements for wings-
level and accelerated turning stalls. We also propose changing the
roll-off requirements for wings-level, high-altitude stalls.
The FAA proposes additional high-speed and high-altitude
requirements to Sec. Sec. 23.251 and 23.253 to address the new
generation of high performance part 23 airplanes. The FAA also proposes
to extend provisions from part 25, Sec. Sec. 25.251(d) and (e), to
part 23. However, we would limit the requirements to airplanes that fly
over 25,000 feet and have a Mach dive speed (MD) faster than
Mach 0.6 (M 0.6) to be consistent with part 25 requirements. The FAA
also proposes the use of VDF/MDF, which is
demonstrated flight dive speed (VDF) or Mach
(MDF) as referenced in the part 23 turbojet special
conditions.
Furthermore, we propose adding requirements in a new Sec. 23.255
that would be based on Sec. 25.255 and would address potential high-
speed Mach effects for airplanes with MD greater than M 0.6.
The FAA's approach would only apply the part 25-based requirements to
airplanes that incorporate a trimmable horizontal stabilizer, which is
consistent with the ARC's recommendation. The ARC's recommendation was
based on the positive service history with the existing fleet of part
23 and part 25 turbojets designed with conventional horizontal tails
that use trimmable elevators. The industry manufacturers have designed
airplanes that have experienced upset incidents involving out-of-trim
conditions with a trimmable horizontal stabilizer. Service experience
shows that out-of-trim conditions can occur in flight for various
reasons, and the control and maneuvering characteristics of the
airplane may be critical in recovering from upsets. The proposed
language would require exploring the airplane's high-speed control and
maneuvering characteristics.
c. Other Design Considerations
We propose to revise language in Sec. 23.703 in the introductory
text and paragraph (b) to add takeoff warning system requirements to
all airplanes over 6,000 pounds and all turbojets. The definition of an
unsafe condition, in this case, is the inability to rotate or prevent
an immediate stall after rotation. High temporary control forces that
can be quickly ``trimmed out'' would not necessarily be considered
unsafe.
We have proposed the commuter category, rejected takeoff
requirements for all multiengine turbojets over 6,000 pounds. The
higher takeoff speeds and distances for these airplanes make the
ability to stop in a specified distance a safety issue. Additional
braking considerations accompany the rejected
[[Page 41526]]
takeoff requirements. Therefore, we propose to apply the requirements
for brakes in Sec. 23.735 to all multiengine turbojets over 6,000
pounds, as well as to all commuter category airplanes.
4. Structural Considerations for Crashworthiness and High-Altitude
Operations
The FAA proposes to codify into Sec. 23.561 the recent turbojet
special conditions that were not available during the ARC's effort.
This proposal applies to single-engine turbojets with centerline
engines embedded in the fuselage. Part 23 did not encompass embedded
centerline engine installations, except for in-line propeller-pusher
types. In light of several new turbojet designs, it is prudent to
require greater engine retention strength for engines mounted aft of
the cabin. This is especially true for engines mounted inside the
fuselage behind the passengers. The proposed requirement would reduce
the potential for the engine to separate from its mounts under forward-
acting crash loads and subsequently intrude into the cabin. We recently
applied this proposed requirement to a single-engine turbojet through
special conditions.
The ARC did not consider emergency landing dynamic conditions in
Sec. 23.562. We recognize, however, that Sec. 23.562 should be
applicable to all turbojets, including those operating in the commuter
category. All manufacturers of recently certificated commuter category
turbojets have agreed to comply with Sec. 23.562. The FAA proposes to
amend Sec. 23.562 to include all commuter category turbojets. This
proposal would adopt current industry practice and ensure a consistent
level of safety for all turbojets.
At one time, the FAA proposed to apply the requirements for
emergency landing dynamic conditions to all commuter category
airplanes.\2\ Subsequently, we published new certification and
operations requirements for commuter operations.\3\ These actions
required certain commuter operators that previously conducted
operations under part 135 to conduct those operations under part 121.
This rule, in effect, eliminated the use of new part 23 airplanes with
10 seats or more in scheduled service. This action negated any
projected benefits supporting the addition of emergency landing dynamic
conditions to commuter category airplanes.
---------------------------------------------------------------------------
\2\ 58 FR 38028.
\3\ 60 FR 65832 and 61 FR 2608.
---------------------------------------------------------------------------
The commuter operators affected were those conducting scheduled
passenger-carrying operations in airplanes that have passenger-seating
configurations of 10 to 30 seats (excluding any crewmember seat) and
those conducting scheduled passenger-carrying operations in turbojet
airplanes regardless of seating configuration. The action increased
safety in scheduled passenger-carrying operations and clarified,
updated, and consolidated the certification and operations requirements
for persons who transport passengers or property by air for
compensation or hire.
In terms of overall configuration, commuter category turbojets have
little resemblance to their propeller-driven counterparts. During an
emergency landing, most commuter category turbojets will have more
structure underneath the cabin floor available to absorb energy than
traditional propeller-driven airplanes. This capability, along with the
differences in the overall airplane configuration of turbojets, would
suggest the test conditions specified in the current rule should be
applicable to all turbojets. However, commuter category airplanes
cannot exceed a maximum takeoff weight of 19,000 pounds. With this
limitation, the amount of crushable, energy absorbing structure is
small when compared to most part 25 airplanes. For this reason, we
propose to require the dynamic test conditions specified in part 23
rather than those in Sec. 25.562.
We also propose to modify the seating head injury criteria (HIC)
calculation in the proposed rule to be consistent with the HIC
definition in part 25. This proposal addresses the concern that the HIC
definition in part 23 would lead to a HIC calculation only for the
total time of the head impact, which would not necessarily maximize
HIC.
In the event of a ditching, the proposed change in Sec. 23.807
would provide an alternative to meeting the current requirement for an
emergency exit, above the waterline, on both sides of the cabin for
multiengine airplanes. Proposed section 23.807 would allow the
placement of a water barrier in the doorway before the door would be
opened as a means to comply with the above waterline exit requirement.
This barrier would be used to slow the inflow of water. The FAA has
approved the use of this barrier as an alternative to the above
waterline exit for several airplanes by issuing an ELOS finding.
Several new part 23 turbojet programs include approval for
operations at altitudes above 40,000 feet. Additionally, the FAA has
issued special conditions for operations up to 49,000 feet. We propose
rule changes for structures and the cabin environment to ensure
structural integrity of the airplane at higher altitudes. We also
propose rule changes to prevent exposure of the occupants to cabin
pressure altitudes that could cause them physiological injury or
prevent the flight crew from safely flying and landing the airplane.
We propose to amend Sec. 23.831 to add new paragraphs (c) and (d),
which include standards appropriate for airplanes operating at high
altitudes beyond those included in part 23. The proposed changes are
intended to ensure flight deck and cabin environments do not result in
the crew's mental errors or physical exhaustion that would prevent the
crew from successfully completing assigned tasks for continued safe
flight and landing. An applicant may demonstrate compliance with
paragraph (d) of this requirement if the applicant can show that the
flight deck crew's performance is not degraded.
The cabin environment must be conservatively specified such that no
occupant would incur any permanent physiological harm after
depressurization. The environmental and physiological performance
limits used for demonstrating compliance must originate from recognized
and cognizant authorities as accepted by the regulatory authority
reviewing the compliance finding.
As part of the certification process, we would consider the entire
flight profile of the airplane during the depressurization event. The
profile would include cruise and transient conditions during descent,
approach, landing, and rollout to a stop on the runway. We would not
include taxiing as a compliance consideration because the airplane
would be on the ground and could be evacuated, or flight deck windows
and cabin doors could be opened for ventilation. The condition of the
airplane from the beginning of the event to the end of the landing roll
is accounted for when assessing the safe exit of an airplane.
We chose the words ``* * * shall not adversely affect crew
performance * * *'' to mean the crew can be expected to reliably
perform either their published or trained duties, or both, to complete
a safe flight and landing. We have measured this in the past by a
person's ability to track and perform tasks. The event should not
result in expecting the crew to perform tasks beyond the procedures
defined by the manufacturer or required by existing regulations. We use
the phrase ``No occupant shall sustain permanent physiological harm''
to mean the occupants who may have required some
[[Page 41527]]
form of assistance, once treated, must be expected to return to their
normal activities.
To show compliance to the proposed rule, the applicant should
consider what would happen to the airplane and systems during
depressurization. The applicant may also consider operational
provisions, which provide for or mitigate the resulting environmental
effects to airplane occupants. If the manufacturer provides an approved
procedure(s) for depressurization, the flight deck and cabin crew may
configure the airplane to moderate either temperature or humidity
extremes, or both, on the flight deck and in the cabin. This
configuration may include turning off non-critical electrical equipment
and opening the flight deck door, or opening the flight deck window(s).
As with Sec. 23.831, we find it necessary to amend the standards
in Sec. 23.841 to prevent exposure of the occupants to cabin pressure
altitudes that could keep the flight crew from safely flying and
landing the airplane or cause permanent physiological injury to the
occupants. The intent of the proposed changes to Sec. 23.841 is to
provide airworthiness standards that allow subsonic, pressurized
turbojets to operate at their maximum achievable altitudes--the highest
altitude an applicant can choose to demonstrate the effects to several
occupant related items after decompression. The applicant must show
that: (1) The flight crew would remain alert and be able to fly the
airplane, (2) the cabin occupants would be protected from the effects
of hypoxia (i.e., deprivation of adequate oxygen supply), and (3) if
some occupants do not receive supplemental oxygen, they would be
protected against permanent physiological harm.
Existing rules require the cabin pressure control system maintain
the cabin at an altitude of not more than 15,000 feet if any probable
failure or malfunction in the pressurization system occurs. Cabin
pressure control systems on part 23 airplanes frequently exhibit a
slight overshoot above 15,000 feet cabin altitude before stabilizing
below 15,000 feet. Existing technology for cabin pressure control
systems on part 23 airplanes cannot prevent this momentary overshoot,
which prevents strict compliance with the rule. We have granted ELOS
findings for this characteristic because physiological data shows the
brief duration of the overshoot would have no significant effect on an
airplane's occupants.
Special conditions issued for part 23 turbojets are similar and,
for operating altitudes above 41,000 feet, equivalent to the
requirements in Sec. 25.841 adopted in Amendment 25-87 (61 FR 28684).
That amendment revised Sec. 25.841(a) to include requirements for
pressurized cabins that were previously covered only in special
conditions. The special conditions required consideration of specific
failures. The FAA incorporated reliability, probability, and damage
tolerance concepts addressing other failures and methods of analysis
into part 25 after the issuance of the special conditions. Sections
23.571, 23.573, and 23.574 address damage tolerance requirements. We
propose to require the use of these additional methods of analysis as
part of this rulemaking.
This proposal also specifies a more performance-based criterion,
such that failures cannot adversely affect crew performance nor result
in permanent physiological harm to passengers.
(Note: There is a different standard for the crew than the
passengers.)
Part 23 requires a warning of an excessive cabin altitude at 10,000
feet. Those regulations do not adequately address airfield operation
above 10,000 feet. Rather than disable the cabin altitude warning to
prevent nuisance warnings, we have issued ELOS findings that allow the
warning altitude setting to be shifted above the maximum approved field
elevation, not to exceed 15,000 feet. We propose to revise Sec. 23.841
to incorporate language from existing ELOSs into the regulation.
Currently, we address oxygen systems for airplanes operating above
41,000 feet using special conditions derived from part 25. A large
number of new turbojets and high-performance airplanes entering part 23
certification will operate at higher altitudes than previously
envisioned for part 23 airplanes. We are proposing revisions to
Sec. Sec. 23.1443, 23.1445, and 23.1447 to establish requirements for
oxygen systems. These new requirements would eliminate the need for
special conditions for airplanes operating above 40,000 feet.
5. General Fire Protection and Flammability Standards for Insulation
Materials
When we initially introduced powerplant fire protection provisions
in part 23, we did not foresee turbojet engines embedded in the
fuselage, nor in pylons on the aft fuselage, for airplanes certificated
to part 23 standards. We propose to add fire protection requirements
for turbojets in Sec. Sec. 23.1193, 23.1195, 23.1197, 23.1199, and
23.1201. Part 23 has historically addressed fire protection through
prevention, identification, and containment. Manufacturers have
provided prevention through minimizing the potential for ignition of
flammable fluids and vapors. Also historically, pilots had been able to
see the engines and identify the fire or use the incorporated fire
detection systems, or both. The ability to see the engine provided for
the rapid detection of a fire, which led to a fire being rapidly
extinguished. However, engine(s) embedded in the fuselage or in pylons
on the aft fuselage do not allow the pilot to see a fire.
Isolating designated fire zones, through flammable fluid shutoff
valves and firewalls, provides for containment of a fire. Containing
fires ensures that components of the engine control system function
effectively to permit a safe shutdown of the engine. We have only
required a demonstration of containment for 15 minutes. If a fire
occurs in a traditional part 23 airplane, the corrective action is to
land as soon as possible. For a small, simple airplane originally
envisioned by part 23, it is possible to descend the airplane to a
suitable landing site within 15 minutes. If the isolation means do not
extinguish the fire, the occupants can safely exit the airplane before
the fire breaches the firewall.
Simple and traditional airplanes normally have the engine located
away from critical flight control systems and the primary structure.
This location has ensured that throughout the fire event, the pilot can
continue safe flight and control of the airplane and predict the
effects of a fire. Other design features of simple and traditional
airplanes (e.g., low stall speeds and short landing distances) ensure
that even if an off-field landing occurs, the potential for a
catastrophic outcome is minimized.
Specifically for airplanes equipped with embedded engines, the
consequences of a fire in an engine embedded in the fuselage are more
varied, adverse, and difficult to predict than the engine fire for a
typical part 23 airplane. Engine(s) embedded in the fuselage offer
minimal opportunity to actually see a fire. The ability to extinguish
an engine fire becomes extremely critical due to this location. With
the engine(s) embedded in the fuselage, an engine fire could affect
both the airplane's fuselage and the empennage structure, which
includes the pitch and yaw controls. A sustained fire could result in
damage to this primary structure and loss of airplane control before a
pilot could make an emergency landing. For embedded engine
installations, we also propose requiring a two-shot fire-extinguishing
system because the metallic components
[[Page 41528]]
in the fire zone can become hot enough to reignite flammable fumes
after someone extinguishes the first fire.
We propose to upgrade flammability standards for thermal and
acoustic insulation materials used in part 23 airplanes. The current
standards do not realistically address situations where thermal or
acoustic insulation materials may contribute to propagating a fire. The
changes we propose are based on the requirements in Sec. 25.856(a),
which were adopted following accidents involving part 25 airplanes,
such as the Swissair MD-11. We believe the proposed standards would
enhance safety by reducing the incidence and severity of cabin fires,
particularly those in inaccessible areas where thermal and acoustic
insulation materials are installed.
The proposed standards include new flammability tests and criteria
that address flame propagation, which would apply to thermal/acoustic
insulation material installed in the fuselage of part 23 airplanes.
Certification tests would consist of samples of thermal/acoustic
insulation that would be exposed to a radiant heat source and a propane
burner flame for 15 seconds. The insulation must not propagate flame
more than 2 inches away from the burner. The flame time after removal
of the burner must not exceed 3 seconds on any specimen. (See proposed
Part II, Appendix F to part 23 for more details.)
Current flammability requirements focus almost exclusively on
materials located in occupied compartments (Sec. 23.853) and cargo
compartments (Sec. 23.855). The potential for an in-flight fire is not
limited to those specific compartments. Thermal/acoustic insulation can
be installed throughout the fuselage in other areas, such as
electrical/electronic compartments or surrounding air ducts, where the
potential also exists for materials to spread fire. Proposed Sec.
23.856 accounts for insulation installed within a specific compartment
in areas the regulations might not otherwise cover. Proposed Sec.
23.856 would be applicable to all part 23 airplanes, regardless of size
or passenger capacity. Advisory material describing test sample
configurations to address design details (e.g., tapes and hook-and-loop
fasteners) is available in DOT/FAA/AR-00/12, Aircraft Materials Fire
Test Handbook, dated April 2000. A copy of the handbook has been placed
in the docket for this rulemaking.
Insulation is usually constructed in what is commonly referred to
as a ``blanket.'' Insulation blankets typically consist of two things:
(1) A batting of a material generically referred to as fiberglass
(i.e., glass fiber or glass wool), and (2) a film covering to contain
the batting and to resist moisture penetration, usually metalized or
non-metalized polyethylene terephthalate (PET), or metalized polyvinyl
fluoride (PVF). Polyimide, a heat-resistant fiber used in insulation
and adhesive, is another film used on certain airplanes. Regardless of
the film type used, there are variations associated with its assembly
for manufacture that result in performance differences from a fire
safety standpoint. These variations include the density of the film,
the type and fineness of the scrim bonded to the film, and the adhesive
used to bond the scrim to the film. The scrim resembles a screen, and
the mesh can vary in fineness. The scrim is usually constructed of
either nylon or polyester and is bonded to the backside of the film to
add shape and strength to the surface area. The adhesive used to bond
the scrim to the film also varies. However, the type of adhesive used
is important because fire retardant is frequently concentrated in the
adhesive of the assembled sheet.
6. Powerplant and Operational Considerations
Current Sec. 23.777 standardizes the height and location of
powerplant controls because pilots may become confused and use the
wrong controls on propeller-driven airplanes. This requirement,
however, does not include single-power levers (which are typical for
electronically-controlled engines). The FAA currently makes an ELOS
finding for each airplane program that includes a single-power lever.
We propose to revise paragraph (d) in Sec. 23.777 to incorporate the
ELOS language.
We propose to revise Sec. 23.903, paragraph (b)(2), to add
requirements for fuselage-embedded, turbofan engine installations.
These types of engine installations may have a negative impact on
passenger safety because passengers occupy an area directly ahead of
the turbojet engine fan disk. Certain turbofan engine designs have
failure conditions that allow the fan disk to exit the front of the
engine. This failure condition occurs if engines have bearing/shaft
configurations that would allow the disk to separate from the engine
and travel forward. If the engine has demonstrated this failure mode or
if an analysis shows such a failure is conceivable, then the
requirements of this section would apply. This requirement would be
applicable to engines embedded in the airplane's fuselage where it
could move forward into areas occupied by passengers or crew when a
disk fails.
In addition to the changes described above, we also propose
requiring that electronic engine control systems meet the equipment,
systems, and installation standards of Sec. 23.1309. We have applied
this requirement to all digital engine controls in part 23 airplanes by
special condition. The proposed rule change for Sec. 23.1141 would
largely eliminate the need to issue special conditions on future
certification programs.
The ARC believed few single-engine airplane manufacturers have
analyzed the criticality of their control system to meet the
requirements of this proposed rule. The fundamental rule change
recommended by the ARC for Sec. 23.1141 was not intended to invalidate
or overrule the 14 CFR part 33 certification requirements. The proposed
change for Sec. 23.1141 is intended for consideration of the airframe/
engine interface and how that interface protects against high intensity
radiated fields (HIRF) and lightning.
Over the years, airplane engines, including turbines, generated
their own ignition system electrical power separate from the airplane's
electrical generation system. Even with a complete electrical failure
of the primary electrical systems, the engines would still run and be
fully functional. However, all new engines are not designed with self-
electrical-generation capability. Some new engines rely on the
airplane's electrical system to continue running and to be fully
functional. Revising Sec. 23.1165(f) would ensure that when approved
engines are installed on part 23 airframes, the engine ignition system
is identified as an essential load. This would ensure that those
engines have power during emergencies.\4\
---------------------------------------------------------------------------
\4\ Under the proposed changes, we would certificate new
engines, which include electronic ignition systems and engines with
electronic controls necessary for the engine's operation, through
the Engine and Propeller Directorate.
---------------------------------------------------------------------------
7. Avionics, Systems, and Equipment Changes
Updated system requirements should reduce the regulatory burden on
the applicant by clarifying and expanding the applicability of
Sec. Sec. 23.1301 and 23.1309 to specific systems and functions. Most
new part 23 airplane manufacturers are installing electronic primary
flight displays (PFD) and multifunction displays (MFD) that replace
conventional electromechanical and mechanical instruments. These new
systems also offer more capability, reliability, and features that
improve safety.
[[Page 41529]]
We propose changes that would address displays, software, hardware,
and power requirements. Besides advanced avionics and integrated
systems, we propose to update the certification requirements to
consider other advanced technologies (e.g., digital engine controls).
We intend to apply lessons learned from recent small turbojet
certification programs to update requirements for intended function and
system safety.
The ARC did not make a specific recommendation for Sec. 23.1301.
However, the FAA seeks to clarify the intent of this section because it
is frequently misinterpreted and misapplied. Clarifying the intent of
Sec. 23.1301 would improve standardization for systems and equipment
certification, particularly for non-required equipment and non-
essential functions embedded within complex avionic systems. Our intent
is for the applicant to define proper functionality and to propose a
means of compliance acceptable to the Administrator. We expect
applicants to coordinate or negotiate deviations from established means
of compliance with the Administrator as early as possible to minimize
delay to project schedules.
We propose to remove Sec. 23.1301(d), which currently states that
equipment must ``function properly when installed.'' The proposed
change would limit the scope of the rule since it would apply only to
equipment required for type certification or operation. We propose a
related change to clarify similar language in Sec. 23.1309 for proper
functionality of installed equipment.
The ARC did not make a specific recommendation for Sec. 23.1303.
However, the FAA seeks to clarify the intent of this rule to
accommodate new technology and eliminate the need to issue an ELOS for
part 23 airplanes. We propose to amend Sec. 23.1303(c) by changing the
current requirement from ``A direction indicator (non-stabilized
magnetic compass)'' to ``A magnetic direction indicator.'' Section
23.1303 does not include a direction indicator, other than the typical
non-stabilized compass for part 23 airplanes. As new technology becomes
more affordable for part 23 airplanes, many electronic flight
instrument systems will use magnetically stabilized direction
indicators (or electric compass systems) to measure and indicate the
airplane heading to provide better performance.
Current regulations require powerplant displays, referred to as
``indicators'' in Sec. 23.1305, to provide trend or rate-of-change
information. Advisory Circular (AC) 23.1311-1B, Installation of
Electronic Displays in Part 23 Airplanes, dated June 14, 2005,
currently provides a basis for an ELOS finding for digital engine
display parameters.\5\ The proposed rule changes to Sec. Sec. 23.1303,
23.1305, and 23.1311 would largely eliminate the need to issue ELOS
findings for these systems and help standardize certification of new
technology.
---------------------------------------------------------------------------
\5\ A copy of the advisory circular is available on the Internet
at http://www.faa.gov/regulations_policies/.
---------------------------------------------------------------------------
The ARC also did not make a specific recommendation for Sec.
23.1307. However, the FAA seeks to clarify language so applicants
understand they may need additional equipment to operate their
airplane. Part 23 is a minimum performance standard, and it may not
include all the required equipment for commercial operations under 14
CFR part 135. We propose to include parts 91 and 135 operations as
examples to use when deciding which equipment is necessary for an
airplane to operate at the maximum altitude.
a. System SafetyAssessment Requirements
We originally designed the system safety assessment requirements of
Sec. 23.1309 to address certification of electronic systems driven by
microprocessors and other complex systems. However, the requirements of
Sec. 23.1309 are being applied to conventional mechanical and
electromechanical systems with well-established design and
certification processes. This was not our intent, and we propose to
revise Sec. 23.1309 to clarify the intended application of the rule.
Proposed changes for Sec. 23.1309 also clarify the intent for
certification of electronic engine controls. The current section
excludes systems certificated with the engine. Therefore, we use
special conditions for all electronic engine control installation
approvals to capture the evaluation requirements of Sec. 23.1309. We
applied special conditions to the interface of the electronic engine
control system and the airplane. We also applied special conditions to
verify that the installation does not invalidate the assumptions made
during part 33 certification of the engine. This proposal would address
electronic engine controls and eliminate the need for special
conditions to apply Sec. 23.1309 to electronic engine control systems.
Proposed Sec. 23.1309(a) would have requirements for two different
types of equipment and systems installed in the airplane. Proposed
Sec. 23.1309(a)(1) would cover the equipment and systems that have no
negative safety effect and those installed to meet a regulatory
requirement. Such systems and equipment are required to ``perform as
intended under the airplane operating and environmental conditions.''
Proposed Sec. 23.1309(a)(2) would require the applicant to show that
all equipment and systems (including approved ``amenities,'' such as a
coffee pot and entertainment systems) have no safety effect on the
operation of the airplane. The phrase ``improper functioning''
identifies equipment and system failures that have a potentially
negative effect on airplane safety. Therefore, we must consider their
potential failure condition(s). Using Sec. 23.1309, we must analyze
any installed equipment or system that has potential failure
condition(s) that are catastrophic, hazardous, major, or minor to
determine their impact on the safe operation of the airplane.
We propose to clarify the certification requirements, environmental
qualification test requirements, and our intent for determining proper
``intended function'' of non-required systems and equipment that do not
have a safety effect on the airplane. A problem with the current
requirements for airplane manufacturers arises when certification
authorities question installation of non-required systems and equipment
that do not perform following their specifications and, therefore, are
``not functioning properly when installed.'' Usually, normal
installation practices can be based on a relatively simple qualitative
installation evaluation. If the possible safety impacts (including
failure modes or effects) are questionable, or isolation between
systems is provided by complex means, more formal structured evaluation
methods or a design change may be necessary. We do not require these
types of equipment and systems to function properly when installed.
However, we would require them to function when they are tested to
verify that they do not interfere with the operation of other airplane
equipment and systems and do not pose a hazard in and of themselves.
Also under proposed changes to Sec. 23.1309(a), we would replace
the conditional qualifiers of ``under any foreseeable operating
condition,'' contained in the current Sec. 23.1309(b)(1), with ``under
the airplane operating and environmental conditions.'' Our intent with
this proposal is for the applicant to take two actions. First, the
applicant must consider the full normal operating envelope of the
airplane, as defined by the airplane flight manual (AFM), with any
modification to that envelope associated with abnormal or emergency
procedures and any anticipated crew
[[Page 41530]]
action. Second, the applicant must consider the anticipated external
and internal airplane environmental conditions, as well as any
additional conditions where equipment and systems are assumed to
``perform as intended.'' We propose to make this change in response to
an observation that although certain operating conditions are
foreseeable, achieving normal performance when they exist is not always
possible (e.g., you may foresee ash clouds from volcanic eruptions, but
airplanes with current technology cannot safely fly in such clouds).
The FAA currently accepts equipment that is susceptible to failures
if these failures do not contribute significantly to the existing risks
(e.g., some degradation in functionality and capability is routinely
allowed during some environmental qualifications, such as HIRF and
lightning testing). System lightning protection specifically allows the
loss of function and capability of some electrical/electronic systems
when the airplane is exposed to lightning, if ``these functions can be
recovered in a timely manner.''
Proposed Sec. 23.1309(a)(3) is applicable for all functional
reliability, flight testing, or flight evaluations. This proposed
change clarifies the FAA's expectations for functional testing during
certification of complex systems, but it is not meant to increase the
testing burden on the applicant. The FAA's intent is to prohibit
certification of systems with known defects in required functions that
could impact safety. For example, it would not be acceptable for an
integrated avionics system to be approved until known functional
defects in required functions are corrected. The system would not be
allowed to exhibit unintended or improper functionality for flight
critical functions. The rate of occurrence of failures, malfunctions,
and design errors must be appropriate for the failure condition(s) of
the type of system and airplane.
Proposed Sec. 23.1309(b) would codify a long-established means of
compliance with current Sec. 23.1309(b) and update failure
condition(s) terminology used in related system safety assessment
documents developed by industry working groups (e.g., RTCA and the
Society of Automotive Engineers (SAE)). This means of compliance
identifies four classes of airplanes as defined in Appendix K of this
proposal and applies appropriate probability values and development
assurance levels for each class. The original text of Sec.
23.1309(b)(4) has been retained and appears as Sec. 23.1309(b)(5) in
this revision. The proposed changes to Sec. 23.1309(c) and (d) are
meant to define the proper scope and intent for applying Sec. 23.1309
depth of analysis for system safety assessments to all systems.
With proposed Sec. 23.1309(f), we would make Sec. 23.1309
compatible with the current Sec. 23.1322 (``Warning, caution, and
advisory lights'') that distinguishes between caution, warning, and
advisory lights installed on the flight deck. Rather than only
providing a warning to the flight crew, which is required by the
current rule, proposed Sec. 23.1309(f) would require that information
concerning an unsafe system operating condition(s) be provided to the
flight crew.
A warning indication would still be required if immediate action by
a flight crewmember were required. The particular method of indication
would depend on the urgency and need for flight crew awareness or
action that is necessary for the particular failure. Inherent airplane
characteristics may be used in lieu of dedicated indications and
annunciations that can be shown to be timely and effective. The use of
periodic maintenance or flight crew checks to detect significant latent
failures when they occur should not be used in lieu of practical and
reliable failure monitoring and indications.
Proposed Sec. 23.1309(f) would clarify the current rule by
specifying that the design of systems and controls, including
indications and annunciations, must reduce crew errors that could
create more hazards. The additional hazards to be minimized would be
those that are caused by inappropriate actions made by a crewmember in
response to the failure, or those that could occur after a failure. Any
procedures for the flight crew to follow after the occurrence of a
failure indication or annunciation would be described in the approved
Airplane Flight Manual (AFM), AFM revision, or AFM supplement, unless
they are accepted as part of normal aviation abilities.
Current Sec. 23.1309 (c) and (d) are not directly related to the
other safety and analysis requirements of Sec. 23.1309. The ARC
considered it appropriate to state the requirements separately for
clarity. We agree with this suggested change and propose to add a new
Sec. 23.1310 to accommodate the change. The requirements as originally
stated in current Sec. 23.1309 would not change, except for a new
section number.
We propose several changes to Sec. 23.1311(a)(5) for plain
language purposes. In proposed Sec. 23.1311(a)(5), we replace the
phrase ``individual electronic display indicators'' with ``electronic
display parameters.'' The term ``indicator'' has a long-standing
definition based on conventional, mechanical indicators; therefore, the
term has caused confusion. These electronic display parameters could be
integrated on one electronic display that is independent of the primary
flight display. In proposed Sec. 23.1311(a)(6), we add the phrase
``that provide a quick-glance sense of rate and, when appropriate,
trend information'' to clarify ``sensory cues.''
We propose to add the term ``when appropriate'' to eliminate the
requirement to display trend information when it would otherwise
provide intuitive information to the pilot. For example, the trend for
fuel burn is always negative. We propose to remove the remainder of
section (a)(6), ``* * * that are equivalent to those in the instrument
being replaced by the electronic display indicator'' to prevent
confusion since most instruments will be electronic. In proposed Sec.
23.1311(a)(7), we have added the word ``equivalent'' to make acceptable
instrument markings on electronic displays that are equivalent to those
instrument markings on conventional mechanical and electromechanical
instruments.
In proposed Sec. 23.1311(b), we replace the phrase ``remain
available to the crew, without need for immediate action'' with ``be
available within one second to the crew with a single pilot action or
by automatic means.'' The proposed language allows an applicant to take
credit for reversionary or secondary flight displays on a multi-
function flight display (MFD) that provides a secondary means of
primary flight information (PFI). This is acceptable if the display can
``be available within one second to the crew with a single pilot action
or by automatic means.'' MFD's may also display PFI as needed to ensure
continuity of operations. The display of PFI on reversionary
(secondary) displays must be arranged in the basic T-configuration.
Also, such displays must be legible and usable from the pilot's
position with minimal head movement to meet the requirements of Sec.
23.1321.
There are three acceptable methods for meeting the requirements of
Sec. 23.1311(b)--(1) Dedicated standby instruments, (2) dual primary
flight displays (PFDs), or (3) reversionary displays that display
independent attitude. The standby instruments, or another independent
PFD, would ensure that primary flight information is available to the
pilot during all phases of flight and system failures. The
[[Page 41531]]
electronic display systems with dual PFDs should incorporate dual,
independently-powered sensors that would provide primary flight
parameters (e.g., attitude heading reference system (AHRS) with
comparators and dual air data computer (ADC)). A reversionary
configuration would have a single pilot action that would force MFD
displays into reversionary mode operation by a single pilot action
within one second or less. However, the PFI must be displayed in
substantially the same format and size in the reversionary mode as it
is in normal mode. The single pilot action should be easily recognized,
readily accessible, and have the control within the pilot's primary
field of view.
The reversionary method could include an automatic reversionary
display with a single pilot action. If PFI on another display is not
provided, we would require automatic switching to ensure PFI is
available to the pilot. This automatic reversionary capability would
cover most possible malfunctions. While a total loss of the display may
not be reliably detected automatically, such a failure condition would
be obvious to the pilot. Malfunctions that result in automatic
switching would be extensive enough to ensure PFI is available at the
reliability level required by Sec. 23.1309. If such a malfunction
occurs, a single pilot action would provide a full display of the
essential information on the remaining display within one second. All
modes, sources, frequencies, and flight plan data would be exactly as
they were on the PFD before the failure.
Another reversionary method would include a means to access the
reversionary mode manually through a single pilot action. Manual
activation of the reversionary mode on the MFD through single action by
the pilot would be acceptable when procedures to activate the PFI are
accomplished before entering critical phases of flight. The PFI would
display continuously on the reversionary display during critical phases
of flight (e.g., takeoff, landing, and missed or final approach).
To meet the proposed turbojet performance requirements in subpart
B, the pilot would need accurate speed indicators while accelerating on
the runway. We propose to revise Sec. 23.1323(e) to add the
requirement to calibrate the airspeed system down to 0.8 of the minimum
value of V1. Also, we propose to adopt the language used in
part 25 for this same requirement because it is more in line with
operating new part 23 turbojets.
The proposed changes to Sec. 23.1331 would apply to instruments
that rely on a power source to provide required flight information for
instrument flight rules (IFR) operations. Consequently, this section
would apply to all flight instruments, such as those required by parts
23, 91, 121, and 135. Airplanes limited by type design to visual flight
rules (VFR) operations would not have to comply with the requirements
of proposed Sec. 23.1331(c).
Each independent power source must provide sufficient power for
normal operations throughout the approved flight envelope of the
airplane and for any operations approved for the airplane. Section
23.1331(c) would not require the installation of dual alternators or
vacuum systems on single-engine airplanes. One option would include a
dedicated battery that meets the requirements of Sec. 23.1353(h) for
electrical instrument loads essential to continued safe flight and
landing. Another option would include separately powered instruments
for primary and standby use. The last option would include performing a
system safety analysis, per Sec. 23.1309, to identify the procedures
necessary to verify the charge state of any airplane starting battery
that is used to power a stand-by system.
The ARC did not make a specific recommendation for Sec. 23.1353.
However, we propose to add additional battery endurance requirements
depending on the airplane's altitude performance. Proposed Sec.
23.1353 addresses the power needs of new all-electrical instruments,
navigation and communications equipment, and engine controls.
When Sec. 23.1353(h) was adopted, part 23 airplanes were mostly
mechanical. We did not envision all-electric, or almost all-electric,
airplanes. Current Sec. 23.1353(h) requires 30 minutes of sufficient
electrical power for a reduced or emergency group of equipment and
instrumentation. We considered 30 minutes adequate to reach VFR
conditions to continue flying to an adequate airport and to accomplish
a safe landing for traditional part 23 airplanes. We did not envision
integrated electric cockpits when we developed Sec. 23.1353(h). New
part 23 airplanes are being certificated with all-electrical
instruments, including the standby instruments. This reliance on
electric power increases the importance of ensuring adequate battery
power until the pilot can descend and make a safe landing.
Most new engines utilize electronic engine controls. These engine
controls may rely on the airplane's electrical system for power and to
control fuel and ignition. Large engines typically installed on part 25
airplanes have a dedicated power source running off the engine; as long
as the engine is running, the electronic engine control has power. Some
of the smaller, simpler engines emerging in part 23 airplanes may not
have these dedicated power sources and may rely on the airplane's
electrical system to keep functioning.
We believe that most new turbine-powered airplanes, and some
turbocharged, piston-powered airplanes, will operate at high altitudes
under IFR. Under these conditions, 30 minutes may not be adequate for
battery power because of the time it would take to descend from maximum
altitude to find visual meteorological conditions (VMC) and land, or to
perform an instrument approach for a landing. For these reasons,
proposed Sec. 23.1353(h) would extend the battery time requirement to
60 minutes for airplanes approved with a maximum altitude above 25,000
feet.
Many new single-engine airplanes are intended for use in part 135
passenger service. Proposed Sec. 23.1353(h) provides consistency with
the operating requirements for single-engine IFR in Sec. 135.163(i).
That section requires a 60-minute battery to power all emergency
equipment, as specified by the manufacturer, to allow continued safe
flight and landing.
b. Allowable Qualitative Failure Condition Probabilities
We propose to add Appendix K to show the appropriate airplane
systems probability standards, failure conditions, and related
development assurance for four certification classes of airplanes
designed to part 23 standards. Proposed Appendix K includes development
assurance levels that correlate to the software levels in RTCA/DO-178B
and the complex design assurance levels in RTCA/DO-254. We provided
quantitative values in Appendix K to indicate the order of probability
range for each certification class and failure condition.
As used in Sec. 23.1309, the FAA proposes the following
definitions for terms used in Appendix K:
i. Extremely remote failure conditions: Those failure conditions
not anticipated to occur to each airplane during its total life but
which may occur a few times when considering the total operational life
of all airplanes of this type. For quantitative assessments, refer to
the probability values shown for hazardous failure conditions in
Appendix K.
ii. Extremely improbable failure conditions: For commuter category
airplanes, those failure conditions so unlikely that they are not
anticipated to occur during the entire operational life of all
airplanes of one type. For other
[[Page 41532]]
classes of airplanes, the likelihood of occurrence may be greater. For
quantitative assessments, refer to the probability values shown for
catastrophic failure conditions in Appendix K.
iii. Probable failure conditions: Those failure conditions
anticipated to occur one or more times during the entire operational
life of each airplane. These failure conditions may be determined on
the basis of past service experience with similar components in
comparable airplane applications. For quantitative assessments, refer
to the probability values shown for minor failure conditions in
Appendix K.
iv. Remote failure conditions: Those failure conditions that are
unlikely to occur to each airplane during its total life but that may
occur several times when considering the total operational life of a
number of airplanes of this type. For quantitative assessments, refer
to the probability values shown for major failure conditions in
Appendix K.
v. Design appraisal: A qualitative appraisal of the integrity and
safety of the system design. An effective appraisal requires
experienced judgment.
vi. Development assurance level: All planned and systematic actions
used to substantiate, to an adequate level of confidence, that errors
in requirements, design, and implementation have been identified and
corrected such that the system satisfies the applicable certification
basis. (The development assurance levels in Appendix K are intended to
correlate to software levels in RTCA/DO-178B and complex hardware
design assurance levels in RTCA/DO-254 for the system or item.)
vii. Simple and conventional systems: A system is considered
``simple'' or ``conventional'' if its function, the technological means
to implement its function, and its intended usage are all the same as,
or closely similar to, that of previously approved systems commonly
used. The systems that have established an adequate service history and
the means of compliance for approval are generally accepted as
``simple'' or ``conventional.'' Simple systems do not contain software
or complex hardware requiring compliance by documents. These documents
are the developmental assurance levels assigned in RTCA/DO-178A/B,
Software Considerations in Airborne Systems and Equipment
Certification, or RTCA/DO-254, Design Assurance Guidance for Airborne
Electronic Hardware documents or later versions.
For simple and conventional installations, it may be possible to
assess a hazardous or catastrophic failure condition(s) as being
extremely remote or extremely improbable, respectively, based on an FAA
approved qualitative analysis. The basis for the assessment would be
the degree of redundancy, the established independence and isolation of
the channels, and the reliability record of the technology involved.
Satisfactory service experience on similar systems commonly used in
many airplanes may be sufficient when a close similarity is established
regarding both the system design and operating conditions.
viii. Installation appraisal: A qualitative appraisal of the
integrity and safety of the installation. Any deviations from normal
industry-accepted installation practices should be evaluated.
8. Placards, Speeds, Operating Limitations, and Information
Currently, Sec. 23.853(d)(2) requires placards for commuter
category airplanes to have red letters at least \1/2\ inch high on a
white background at least 1 inch high. The letter size is not a
requirement for the part 23 normal category or for the part 25
transport category airplanes. We propose removing the letter size
requirement from this section. We also propose removing the ashtray
requirement from this section since smoking is no longer allowed in
parts 121 and 135 operations. We propose to amend paragraph (d)(2) of
this section to read ``Lavatories must have `No Smoking' or `No Smoking
in Lavatory' placards located conspicuously on each side of the entry
door.''
Proposed Sec. 23.629 would allow the use of VDF in
place of VD for flight testing turbojets. In addition, the
proposed amendment for Sec. 23.1505 would require airspeed limits
based on a combination of analytical (VD/MD) and
demonstrated (VDF/MDF) dive speeds for turbojets.
Proposed Sec. 23.1505(c) would include specific turbojet speed
designations.
The ARC did not make a specific recommendation regarding Sec.
23.1525. However, we propose to clarify language so applicants
understand that additional equipment may be needed to operate their
airplane. Part 23 is a minimum performance standard, and it may not
include all the required equipment for operations under part 135. We
propose to include parts 91 and 135 operations as examples of the kinds
of operation authorized.
Proposed Sec. 23.1545 limits the white flap arc to reciprocating
engine airplanes. This change reflects standard practice for turbojets
and is included in all part 23 turbojet special conditions.
Proposed Sec. 23.1555(d)(3) would require fuel systems with a
calibrated fuel quantity indication system to comply with Sec.
23.1337(b)(1) while removing current placard requirements. Most modern
turbine-powered airplanes have a calibrated fuel quantity indicating
system that is density compensated and accurately indicates the actual
usable fuel quantity in each tank. When using these types of fuel
indicating systems, we consider the placards required by Sec. Sec.
23.1555(d)(1) and (2) redundant. The placards or markings required by
Sec. Sec. 23.1555(d)(1) and (2) indicate the maximum capacity of the
tank. For these reasons, we propose to remove the placard requirement
for these accurate fuel quantity indicating systems.
The placard requirements of Sec. Sec. 23.1559, 23.1563 and 23.1567
have been a source of confusion to both FAA and industry personnel
relative to placard lighting. We are proposing changes to these three
rules to clarify the intent of these requirements. The requirements
specified on the placard in Sec. 23.1559 are relative to preflight
planning, and this placard is not normally referenced in flight. As
long as the placard is ``in clear view of the pilot'' and the pilot can
view it at night using a flashlight or other means, the intent of the
rule is met. The requirement has been confusing for certification
offices and this proposal makes the placard lighting intent clear. We
propose to add a new paragraph Sec. 23.1559(d), which states ``The
placard required by this section need not be lighted.''
With modern flight display equipment, the necessary information may
now be available on that equipment and is automatically illuminated as
part of the display. Therefore, we also propose to update Sec. 23.1563
to clarify requirements for night lighting of the placard. Maneuvering
speed is applicable to operations that may involve intentional large
control input and is therefore not applicable to normal night
operations. Most modern airplanes have means for the landing gear speed
to be displayed in the airspeed indicator or on lighted portions of the
landing gear control. They have the means for the airspeed indicator to
display low speed awareness or other airspeed reference information to
provide safety above VMC. Lighting this placard is
unnecessary for safety and provides another source of unwanted lighting
reflections in the cockpit.
The requirements specified in Sec. 23.1567 for the limitation
placard relate to acrobatic maneuvers and spin information related to
preflight
[[Page 41533]]
planning. Since these maneuvers are not normally conducted during night
operations, the placard information is not required for night flight.
If the placard is ``in clear view of the pilot'' and the pilot can view
the placard at night using a flashlight or other means, it meets the
intent of the rule. The proposed change to Sec. 23.1567 clarifies our
intent of this rule relative to lighting.
We propose to incorporate the existing special conditions into the
AFM requirements in Sec. Sec. 23.1583, 23.1585, and 23.1587. These are
necessary to be consistent with the performance requirements proposed
in subpart B. These requirements include the ARC recommended, single-
engine climb performance increase for turboprops.
III. Regulatory Notices and Analyses
Paperwork Reduction Act
According to the 1995 amendments to the Paperwork Reduction Act (5
CFR 1320.8(b)(2)(vi)), an agency may not collect or sponsor the
collection of information, nor may it impose an information collection
requirement unless it displays a currently valid OMB control number.
The OMB control number for this information collection will be
published in the Federal Register, after the Office of Management and
Budget approval.
International Compatibility
In keeping with U.S. obligations under the Convention on
International Civil Aviation, it is FAA policy to comply with
International Civil Aviation Organization (ICAO) Standards and
Recommended Practices to the maximum extent practicable. The FAA has
reviewed the corresponding ICAO Standards and Recommended Practices and
has identified no differences with these proposed regulations.
Regulatory Evaluation, Regulatory Flexibility Determination,
International Trade Impact Assessment, and Unfunded Mandates Assessment
Changes to Federal regulations must undergo several economic
analyses. First, Executive Order 12866 directs that each Federal agency
shall propose or adopt a regulation only upon a reasoned determination
that the benefits of the intended regulation justify its costs. Second,
the Regulatory Flexibility Act of 1980 (Pub. L. 96-354) requires
agencies to analyze the economic impact of regulatory changes on small
entities. Third, the Trade Agreements Act (Pub. L. 96-39) prohibits
agencies from setting standards that create unnecessary obstacles to
the foreign commerce of the United States. In developing U.S.
standards, this Trade Act requires agencies to consider international
standards and, where appropriate, that they be the basis of U.S.
standards. Fourth, the Unfunded Mandates Reform Act of 1995 (Pub. L.
104-4) requires agencies to prepare a written assessment of the costs,
benefits, and other effects of proposed or final rules that include a
Federal mandate likely to result in the expenditure by State, local, or
tribal governments, in the aggregate, or by the private sector, of $100
million or more annually (adjusted for inflation with base year of
1995). This portion of the preamble summarizes the FAA's analysis of
the economic impacts of this proposed rule. We suggest readers seeking
greater detail read the full regulatory evaluation, a copy of which we
have placed in the docket for this rulemaking.
In conducting these analyses, FAA has determined that this proposed
rule: (1) Has benefits that justify its costs, (2) is not an
economically ``significant regulatory action'' as defined in section
3(f) of Executive Order 12866, (3) the Office of Management and Budget
has determined this proposal is ``significant''; (4) would not have a
significant economic impact on a substantial number of small entities;
(5) would not create unnecessary obstacles to the foreign commerce of
the United States; and (6) would not impose an unfunded mandate on
state, local, or tribal governments, or on the private sector by
exceeding the threshold identified above. These analyses are summarized
below.
Total Benefits and Costs of This Rule
The estimated base case cost of this proposed rule is about
$472,000 ($443,000 in 7 percent present value terms). The estimated
safety benefits would be to avoid 14 accidents and are valued at about
$82.7 million. The estimated base case efficiency benefits to
streamline the part 23 certification process are valued at about $1.6
million. The total base case benefit is equal to the sum of the safety
and efficiency benefits and is valued at about $84.2 million.
Who Is Potentially Affected by This Rule
This proposed rulemaking will affect manufacturers and operators of
part 23 reciprocal engine, turboprop and turbojet airplanes.
Assumptions
The proposed rule makes the following assumptions:
1. The base year is 2008.
2. The average retirement age of a U.S. operated part 23 airplane
is 32 years.
3. The average part 23 airplane production life cycle is 24 years.
4. The analysis period extends for 56 (32 + 24) years.
5. U.S companies would manufacture 75 percent of the turbojets
forecasted by the FAA.
6. All business and commercial part 23 airplanes would operate in
commuter service.
7. The value of a fatality avoided is $5.8 million.
Benefits of This Rule
For part 23 airplanes, we estimated that the proposed changes would
avoid about 14 accidents over the 24-year operating lives of 37,657
new-production airplanes. The resulting benefits include averted
fatalities and injuries, loss of airplanes, investigation cost, and
collateral damages for the accidents. The safety benefits for averting
the 14 accidents are about $82.7 million ($17.8 million in 7 percent
present value terms).
Other benefits of this proposal include FAA and industry paperwork
and certification time saved by standardizing and streamlining the
certification of part 23 airplanes. The base case efficiency benefits
for standardizing and streamlining the certification process is valued
at $1.6 million.
The total base case benefit is equal to the sum of the safety and
efficiency benefits and is about $84.2 million ($19.3 million in 7
percent present value terms).
Costs of This Rule
Constant-dollar (2008$) unit costs per aircraft by 14 CFR Part 23
could be as high as: $165 for turboprop airplanes and $6,550 for
turbojet airplanes. Total incremental costs equal the constant-dollar
unit costs multiplied by the number of aircraft produced over 10 years.
The base case costs of this rule are about $472,000 ($443,000 in 7
percent present value terms) and the high case costs of this rule are
about $11.1 million ($5.0 million in 7 percent present value terms).
Alternatives Considered
Alternative 1--The FAA would continue to issue special exemptions,
exceptions and equivalent levels of safety to certificate part 23
airplanes. As that would perpetuate ``rulemaking by exemption,'' we
choose not to continue with the status quo.
Alternative 2--The FAA continue to enforce the current regulations
that affect single engine climb performance.
[[Page 41534]]
The FAA rejected this alternative because the accident rate on twin
piston engine and turboprop airplanes identified a safety issue that
had to be addressed.
Regulatory Flexibility Determination
The Regulatory Flexibility Act of 1980 (Pub. L. 96-354) (RFA)
establishes ``as a principle of regulatory issuance that agencies shall
endeavor, consistent with the objectives of the rule and of applicable
statutes, to fit regulatory and informational requirements to the scale
of the businesses, organizations, and governmental jurisdictions
subject to regulation. To achieve this principle, agencies are required
to solicit and consider flexible regulatory proposals and to explain
the rationale for their actions to assure that such proposals are given
serious consideration.'' The RFA covers a wide-range of small entities,
including small businesses, not-for-profit organizations, and small
governmental jurisdictions.
Agencies must perform a review to determine whether a rule will
have a significant economic impact on a substantial number of small
entities. If the agency determines that it will, the agency must
prepare a regulatory flexibility analysis as described in the RFA.
However, if an agency determines that a rule is not expected to have a
significant economic impact on a substantial number of small entities,
section 605(b) of the RFA provides that the head of the agency may so
certify and a regulatory flexibility analysis is not required. The
certification must include a statement providing the factual basis for
this determination, and the reasoning should be clear.
The FAA believes that this proposed rule would not have a
significant impact on a substantial number of entities. The purpose of
this analysis is to provide the reasoning underlying the FAA
determination.
First, we will discuss the reasons why the FAA is considering this
action. We will follow with a discussion of the objective of, and legal
basis for, the proposed rule. Next we explain there are no relevant
federal rules which may overlap, duplicate, or conflict with the
proposed rule. Lastly, we will describe and provide an estimate of the
number of small entities affected by the proposed rule and why the FAA
believes this proposed rule would not result in a significant economic
impact on a substantial number of small entities.
We now discuss the reasons why the FAA is considering this action.
The FAA proposes this action to amend safety and applicability
standards of the part 23 turbojet industry to reflect the current needs
of the industry, accommodate future trends, address emerging
technologies, and provide for future aircraft operations. This proposal
primarily standardizes and streamlines the certification of part 23
turbojet airplanes. The intent of the proposed changes to parts 1 and
23 are necessary to eliminate the current workload of exemptions,
special conditions, and equivalent levels of safety determinations
necessary to certificate part 23 turbojets. These proposed part 23
changes will also clarify areas of frequent non-standardization and
misinterpretation and provide appropriate safety and applicability
standards that reflect the current state of the industry, emerging
technologies and new types of operations for all part 23 airplanes;
including turbojet, turboprop and reciprocating engine airplanes.
The FAA currently issues type certificates (TCs) for part 23
turbojets using extensive special conditions. Issuance of TCs has not
been significant until now because there were few part 23 turbojet
programs. However, in the past five years, the number of new turbojet
certification programs in part 23 has increased more than 100 percent
over the past three decades.
The need to incorporate these special conditions into part 23 stems
from both the existing number of new jet programs and the expected
future jet programs. Codifying these special conditions will allow
manufacturers to know the requirements during their design phase
instead of designing the turbojet and then having to apply for special
conditions that may ultimately require a redesign. Codifying will also
reduce the manufacturers and FAA's paper process required to TC an
airplane and reduces the potential for program delays. These proposed
changes would also clarify areas of frequent non-standardization and
misinterpretation, particularly for electronic equipment and system
certification.
The revisions include general definitions, error correction, and
specific requirements for performance and handling characteristics to
ensure safe operation of part 23 transport category airplanes. The
proposed revisions would apply to all future new part 23 turbojet,
turboprop and reciprocating engine airplane certifications.
We now discuss the legal basis for, and objective of, the proposed
rule. Next, we discuss if there are relevant federal rules, which may
overlap, duplicate, or conflict with the proposed rule.
The FAA's authority to issue rules on aviation safety is found in
Title 49 of the United States Code. Subtitle I, Section 106 describes
the authority of the FAA Administrator. Subtitle VII, Aviation
Programs, describes in more detail the scope of the agency's authority.
This rulemaking is promulgated under the authority described in
Subtitle VII, Part A, Subpart III, Section 44701. Under that section,
the FAA is charged with promoting safe flight of civil aircraft in air
commerce by prescribing minimum standards required in the interest of
safety for the design and performance of aircraft. This regulation is
within the scope of that authority because it prescribes new safety
standards for the design of part 23 normal, utility, acrobatic, and
commuter category airplanes.
Accordingly, this proposed rule will amend Title 14 of the Code of
Federal Regulations to address deficiencies in current regulations
regarding the certification of part 23 light jets, turboprops and
reciprocating engine airplanes. The proposed rule would clarify areas
of frequent non-standardization and misinterpretation and codify
certification requirements that currently exist in special conditions.
The FAA is unaware the proposed rule will overlap, duplicate, or
conflict with existing Federal Rules.
We now discuss our methodology to determine the number of small
entities for which the proposed rule will apply.
Under the RFA, the FAA must determine whether a proposed rule
significantly affects a substantial number of small entities. This
determination is typically based on small entity size and cost
thresholds that vary depending on the affected industry.
Using the size standards from the Small Business Administration for
Air Transportation and Aircraft Manufacturing, we defined companies as
small entities if they have fewer than 1,500 employees.\6\
---------------------------------------------------------------------------
\6\ 13 CFR 121.201, Size Standards Used to Define Small Business
Concerns, Sector 48-49 Transportation, Subsector 481 Air
Transportation.
---------------------------------------------------------------------------
There are 11 U.S. aircraft manufacturers currently producing part
23 airplanes and could be affected by this proposal. These
manufacturers are American Champion, Cessna, Cirrus, Eclipse, Hawker
Beechcraft, Liberty, Maule, Mooney, Piper, Quest, and Sino Swearingen.
Using information provided by the World Aviation Directory,
Internet filings and industry contacts, manufacturers that are
subsidiary
[[Page 41535]]
businesses of larger businesses, manufacturers that are foreign owned,
and businesses with more than 1,500 employees were eliminated from the
list of entities. Cessna and Hawker Beechcraft are businesses with more
than 1,500 employees and Cirrus and Liberty are foreign owned. We found
no source of employment or revenue data for American Champion. For the
remaining businesses, we obtained company revenue and employment from
the above sources.
The base year for the proposed rule is 2008. Although the FAA
forecasts traffic and air carrier fleets, we can not determine the
number of new entrants nor who will be in business in the future.
Therefore we use current U.S. manufacturer's revenue and employment in
order to determine the number of operators this proposal would affect.
The methodology discussed above resulted in the following six U.S.
part 23 aircraft manufacturers, with less than 1,500 employees, shown
in Table RF1.
Table RF1
------------------------------------------------------------------------
Company Employees Annual revenue
------------------------------------------------------------------------
Quest................................. 60 $4,600,000
Maule................................. 86 5,700,000
Piper................................. 100 7,600,000
Mooney................................ 400 42,083,000
Sino Swearingen....................... 400 25,300,000
Eclipse............................... 1,000 36,700,000
------------------------------------------------------------------------
The majority of this proposal affects the certification of
turbojets and has a minor affect on the certification of turboprop and
reciprocating engine airplanes by clarifying frequent non-
standardization and misinterpretations of the current part 23 rules.
From the list of part 23 small entity U.S. airplane manufacturers
above, only Eclipse and Sino Swearingen produce turbojet airplanes and
Piper and Quest produce turboprop airplanes. The remaining part 23
small entity U.S. airplane manufacturers produce reciprocating engine
airplanes.
In the regulatory evaluation, we estimated that operators of newly
certificated part 23 airplanes would incur additional fuel costs.
Additionally, operators could incur costs from added weight and a
reduced payload capacity. The U.S. Census Bureau data on the Small
Business Administration's Web site shows an estimate of the total
number of small business entities who could be affected if they
purchase newly certificated part 23 airplanes.\7\ The U.S. Census
Bureau data lists 39,754 small entities in the Non-scheduled Air
Transportation Industry that employ less than 500 employees. Many of
these non-scheduled businesses are in part 25. Other small businesses
may own aircraft and not be included in the U.S. Census Bureau Non-
scheduled Air Transportation Industry category. The estimate of the
affect of this proposal on the total number of small entities that
operate part 23 airplanes is developed below.
---------------------------------------------------------------------------
\7\ http://www.sba.gov/advo/research/us05_n6.pdf.
---------------------------------------------------------------------------
We now discuss our methodology to estimate the costs of this
proposal to the small entities part 23 airplane manufacturers and
operators. We will also discuss why the FAA believes this proposed rule
would not result in a significant economic impact to part 23 airplane
manufacturers and operators.
In 2003, we published a notice (68 FR 5488) creating the part 125/
135 Aviation Rulemaking Committee (ARC). FAA and the part 23 industry
have worked together to develop common certification part 23 airplane
requirements proposed in this rulemaking. We contacted the part 23
aircraft manufacturers, the ARC, and General Aviation Manufacturers
Association (GAMA) (an industry association for part 23 aircraft
manufacturers) for specific cost estimates for each proposed section
change for this rule. Not every party we contacted responded to our
request for costs. Many of the ARC members, from the domestic and
international manufacturing community, collaborated and filed a joint
cost estimate for this proposed rule. We are basing our cost estimates
for this proposed rule from these part 23 U.S. aircraft manufacturers,
ARC members and GAMA.
The part 23 U.S. airplane manufacturers, ARC members, and industry
association informed us that this proposed rulemaking would add
manufacturer certification costs for fire extinguishing systems, climb,
and take-off warning systems. Industry informed us that this proposal
would save the manufacturers design time for the certification of
cockpit controls. Industry has also informed us that every other
proposed section of this rule is either clarifying, error correcting,
or would only add minimal to no costs.
The proposed rule adds certification requirements for the following
part 23 airplane categories:
1. All turbojet airplanes,
2. All turbojet airplanes with a MTOW less than 6,000 pounds,
3. All turboprop airplanes,
4. All reciprocal engine airplanes, and
5. All reciprocal twin engine airplanes with a MTOW greater than
6,000 pounds.
In some cases the proposed regulations only affect part 23
airplanes operated in revenue service. Any part 23 airplane could be
used as a business airplane to haul passengers and cargo in commercial
service. We estimated the business versus personal use of a part 23
airplane by analyzing the number of all US-operated airplanes from
Table 3.1 of the 2006 General Aviation and Part 135 Activity Survey.
Table 3.1 shows the breakout of the 2006 General Aviation fleet by
business, corporate, instructional, aerial applications, aerial
observations, aerial other, external load, other work, sight see, air
medical, other, part 135 Air Taxi, Air Tours, and Air Medical airplane
usage. For the purpose of estimating the cost of this proposal, we
assume all business part 23 airplane operators from Table 3.1 of the
2006 General Aviation and Part 135 Activity Survey would operate in
Commuter service. Table RF2 shows these results.
[[Page 41536]]
Table RF2--2006 General Aviation and Part 135 Activity Survey--Table 3.1
----------------------------------------------------------------------------------------------------------------
Aircraft type Total active Personal % Personal % Business
----------------------------------------------------------------------------------------------------------------
Piston.......................................... 163,743 118,618 72.44 27.56
Turboprop....................................... 8,063 1,177 14.60 85.40
Turbojet........................................ 10,379 750 7.23 92.77
----------------------------------------------------------------------------------------------------------------
Table RF3 shows the results of the proposed sections that add (or
subtract) incremental costs by increasing design or flight testing
times, adds weight, or reducing payload.
Table RF3
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Certification Flight Operation Part 23 Airplane Categories Affected
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Twin
Turbojet reciprocal
Design Flight Additional Payload <6,000 Reciprocal engine
Part 23 Section Section title hours test weight reduction Turbojet Turboprop engine >6,000 Category
hours MTOW
MTOW
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
23.1193(g), 23.1195(a), 23.1197, Cowling and Nacelle, ......... 50 25 .......... .......... .......... X .......... .......... Commuter.
23.1199, 23.1201. Fire Extinguisher
Systems, Fire
Extinguishing Agents,
Extinguishing Agent
Containers, Fire
Extinguishing System
Materials.
23.63, 23.67, 23.77.................. Climb: General, Climb-- ......... ......... .......... 10% .......... X X .......... X All.
One Engine, Balked
Landing.
23.703............................... Take-Off Warning System. 1,000 25 .......... .......... .......... X X .......... X All.
23.777............................... Cockpit Controls........ -25 ......... .......... .......... X .......... X X .......... All.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
We estimated part 23 airplane manufacturer fixed (added
certification plus flight test hours) and operator variable (added fuel
burn plus 10 percent reduction in payload) costs and applied our
estimated costs to expected fleet delivered in compliance with this
proposal. The total cost of this rule is the sum of the fixed
certification cost plus the airplane fuel-burn variable cost multiplied
by the expected fleet delivered over the analysis period.
The total fixed certification compliance cost equals the average
compliance cost multiplied by the expected number of certifications of
newly delivered part 23 turbojet, turboprop and reciprocating engine
airplane. In the regulatory evaluation we estimated a base case and
high case range for the certification costs. This range was based on
the estimated number of new turbojet certifications. In the base case,
we estimated five new turbojet certifications in the analysis interval.
In the high case, we estimated eight new turbojet certifications. We
will use the high cost case scenario for this analysis.
We estimated the certification costs for fire extinguishing
systems, climb, and take-off warning systems. Based on the hours
provided by the part 23 U.S. airplane manufacturers, ARC members and
industry association and the Economic Values For FAA Investment and
Regulatory Decisions, A Guide for the hourly rates.\8\ Table RF4 shows
the incremental certification costs estimate we calculated.
---------------------------------------------------------------------------
\8\ http://www.faa.gov/regulations_policies/policy_guidance/benefit_cost/media/050404%20Critical%20Values%20Dec%2031%20Report%2007Jan05.pdf.
Table RF4--High Cost Scenario for Part 23 Manufacturers
----------------------------------------------------------------------------------------------------------------
Costs Recip Commuter TP TJ < 6,000
----------------------------------------------------------------------------------------------------------------
Design.......................................................... $0 $152,020 $94,496
Design.......................................................... (9,501) (3,801) (22,803)
Flight Test..................................................... 0 114,400 93,489
Total High Cost................................................. (9,501) 262,620 165,181
Certifications........................................ 5 4 12
Cost per Cert................................................... (1,900) 65,655 13,765
----------------------------------------------------------------------------------------------------------------
We applied the estimated incremental certification costs to the
each of the small part 23 airplane manufacturing average number of
historical certifications over a ten-year period. We then divided the
small part 23 airplane
[[Page 41537]]
manufacturer's annual revenue by the incremental costs. Table RF5 shows
these results.
Table RF5
--------------------------------------------------------------------------------------------------------------------------------------------------------
Annual Average certs 10 Estimated cert
Company Employees revenue years Airplane certificated cost Percent
--------------------------------------------------------------------------------------------------------------------------------------------------------
Quest......................... 60 $4,600,000 1.00....................... Turboprop.................. $65,655 1.43
Maule......................... 86 5,700,000 0.20....................... Recip...................... -380 -0.01
Piper......................... 100 7,600,000 1.00 (Recip) + 33 (TP)..... Recip + Turboprop.......... 65,022 0.86
Mooney........................ 400 42,083,000 0.17....................... Recip...................... -317 0.00
Sino Swearingen............... 400 25,300,000 1.00....................... Turbojet................... 13,765 0.05
Eclipse....................... 1,000 36,700,00 1.00....................... Turbojet................... 13,765 0.04
--------------------------------------------------------------------------------------------------------------------------------------------------------
We estimated that the incremental fixed certification cost this
proposed rule would be less than one percent in five of the six small
entity part 23 airplane manufacturers, and less than 1.5 percent in the
remaining one. We do not believe these are significant economic costs.
Further, we believe that the manufacturers of the part 23 airplanes
would have additional costs savings associated with the proposal
standardizes and streamlining the certification process. Additional
costs savings of the proposed changes to parts 1 and 23 would be to
eliminate the current workload of exemptions, special conditions, and
equivalent levels of safety necessary to certificate part 23 turbojets
and by clarifying frequent non-standardization and misinterpretations
of current part 23 rules.
To estimate the incremental variable costs to a part 23 operator,
we multiplied the annual per-unit fuel burn cost by the expected fleet
delivered over the analysis interval.
In the regulatory evaluation, we estimated a minimal base and high
case cost for the 10 percent loss in capacity occurs the operators may
incur. The base case was a no cost scenario because the average GA
airplane has about 3.7 seats and flies about half full.\9\ The cargo
load factor for all cargo carriers is 60 percent.\10\ Therefore, we
conclude that the 10 percent reduction in payload caused by the
proposed sections on climb and balked landings could have a minimum
cost impact on part 23 airplanes for the base case. For the high case
we realize that a percentage of the part 23 airplanes, in commuter
service, could have a load factor over 90 percent on some of their
flights. Although we believe any capacity affected would be distributed
over other flights in the operator's network, we estimate the cost of a
10 percent payload capacity reduction. Table RF6 shows the results of
our calculations.
---------------------------------------------------------------------------
\9\ Table 3.15 of the Economic Values For FAA Investment and
Regulatory Decisions, A Guide
\10\ Ibid.
Table RF6
----------------------------------------------------------------------------------------------------------------
Recip TurboProp Commuter TP Total TJ TJ<6,000
----------------------------------------------------------------------------------------------------------------
Base Case Cost.................. $0 $0 $8,430 $0 $0
High Case Cost.................. $0 $0 $1,413,692 $0 $3,086,919
Number of A/P................... 23,160 1,248 1,066 11,040 1,143
Base Case Cost / A/P............ $0 $0 $8 $0 $0
High Case Cost / A/P............ $0 $0 $1,326 $0 $2,700
A/P Value....................... $431,681 $3,389,054 $3,389,054 $6,300,000 $6,300,000
% Base of Value................. 0.00% 0.00% 0.00% 0.00% 0.00%
% High of Value................. 0.00% 0.00% 0.04% 0.00% 0.04%
----------------------------------------------------------------------------------------------------------------
For this proposal, our high case estimate for small business part
23 operators of turboprop airplanes would pay an additional $1,326 to
operate a newly certificated airplane. Operators of newly certificated
and delivered part 23 turbojet airplanes with a maximum take off weight
less than 6,000 pounds would pay an additional $2,700 to operate a
newly certificated airplane. Operators would not incur these costs
unless they purchase a newly certificated part 23 airplane.
We do not believe that these proposals costs would be a significant
impact to small entity operators because, even for the high-cost case,
the compliance costs of this proposal to operators would only be 0.04
percent for a turboprop and 0.04 percent for a turbojet with a maximum
take-off weight less than 6,000 pounds, of the price of a newly
certificated airplane.
Therefore the FAA certifies that this proposed rule would not have
a significant economic impact on a substantial number of small
entities. The FAA solicits comments regarding this determination.
International Trade Impact Assessment
The Trade Agreements Act of 1979 (Pub. L. 96-39) prohibits Federal
agencies from establishing any standards or engaging in related
activities that create unnecessary obstacles to the foreign commerce of
the United States. Legitimate domestic objectives, such as safety, are
not considered unnecessary obstacles. The statute also requires
consideration of international standards and, where appropriate, that
they be the basis for U.S. standards. The FAA has assessed the
potential effect of this final rule and has no basis for believing the
rule will impose substantially different costs on domestic and
international entities. Thus the FAA believes the rule has a neutral
trade impact.
Unfunded Mandates Assessment
Title II of the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-
4) requires each Federal agency to prepare
[[Page 41538]]
a written statement assessing the effects of any Federal mandate in a
proposed or final agency rule that may result in an expenditure of $100
million or more (in 1995 dollars) in any one year by State, local, and
tribal governments, in the aggregate, or by the private sector; such a
mandate is deemed to be a ``significant regulatory action.'' The FAA
currently uses an inflation-adjusted value of $136.1 million in lieu of
$100 million. This proposed rule does not contain such a mandate;
therefore, the requirements of Title II of the Act do not apply.
Executive Order 13132, Federalism
The FAA has analyzed this proposed rule under the principles and
criteria of Executive Order 13132, Federalism. We determined that this
action would not have a substantial direct effect on the States, on the
relationship between the national Government and the States, or on the
distribution of power and responsibilities among the various levels of
government, and, therefore, would not have federalism implications.
Regulations Affecting Intrastate Aviation in Alaska
Section 1205 of the FAA Reauthorization Act of 1996 (110 Stat.
3213) requires the Administrator, when modifying regulations in Title
14, Code of Federal Regulations in a manner affecting intrastate
aviation in Alaska, to consider the extent to which Alaska is not
served by transportation modes other than aviation and to establish
appropriate regulatory distinctions. Because this proposed rule would
apply to the certification of future designs of transport category
airplanes and their subsequent operation, it could, if adopted, affect
intrastate aviation in Alaska. The FAA, therefore, specifically
requests comments on whether there is justification for applying the
proposed rule differently in intrastate operations in Alaska.
Environmental Analysis
FAA Order 1050.1E identifies FAA actions that are categorically
excluded from preparation of an environmental assessment or
environmental impact statement under the National Environmental Policy
Act in the absence of extraordinary circumstances. The FAA has
determined this proposed rulemaking action qualifies for the
categorical exclusion identified in paragraph 312(f) and involves no
extraordinary circumstances.
Regulations That Significantly Affect Energy Supply, Distribution, or
Use
The FAA has analyzed this NPRM under Executive Order 13211, Actions
Concerning Regulations that Significantly Affect Energy Supply,
Distribution, or Use (May 18, 2001). We have determined that it is not
a ``significant energy action'' under the executive order because while
it is a ``significant regulatory action,'' it is not likely to have a
significant adverse effect on the supply, distribution, or use of
energy.
Additional Information
Comments Invited
The FAA invites interested persons to participate in this
rulemaking by submitting written comments, data, or views. We also
invite comments relating to the economic, environmental, energy, or
federalism impacts that might result from adopting the proposals in
this document. The most helpful comments reference a specific portion
of the proposal, explain the reason for any recommended change, and
include supporting data. To ensure the docket does not contain
duplicate comments, please send only one copy of written comments, or
if you are filing comments electronically, please submit your comments
only one time.
We will file in the docket all comments we receive, as well as a
report summarizing each substantive public contact with FAA personnel
concerning this proposed rulemaking. Before acting on this proposal, we
will consider all comments we receive on or before the closing date for
comments. We will consider comments filed after the comment period has
closed if it is possible to do so without incurring expense or delay.
We may change this proposal in light of the comments we receive.
Proprietary or Confidential Business Information
Do not file in the docket information that you consider to be
proprietary or confidential business information. Send or deliver this
information directly to the person identified in the FOR FURTHER
INFORMATION CONTACT section of this document. You must mark the
information that you consider proprietary or confidential. If you send
the information on a disk or CD ROM, mark the outside of the disk or CD
ROM, and also identify electronically within the disk or CD ROM the
specific information that is proprietary or confidential.
Under 14 CFR 11.35(b), when we are aware of proprietary information
filed with a comment, we do not place it in the docket. We hold it in a
separate file to which the public does not have access, and we place a
note in the docket that we have received it. If we receive a request to
examine or copy this information, we treat it as any other request
under the Freedom of Information Act (5 U.S.C. 552). We process such a
request under the DOT procedures found in 49 CFR part 7.
Availability of Rulemaking Documents
You can get an electronic copy of rulemaking documents using the
Internet by--
1. Searching the Federal eRulemaking Portal (http://www.regulations.gov);
2. Visiting the FAA's Regulations and Policies web page at http://www.faa.gov/regulations_policies/; or
3. Accessing the Government Printing Office's Web page at http://www.gpoaccess.gov/fr/index.html.
You can also get a copy by sending a request to the Federal
Aviation Administration, Office of Rulemaking, ARM-1, 800 Independence
Avenue SW., Washington, DC 20591, or by calling 202-267-9680. Make sure
to identify the docket number or notice number of this rulemaking.
You may access all documents the FAA considered in developing this
proposed rule, including economic analyses and technical reports, from
the Internet through the Federal eRulemaking Portal referenced in
paragraph (1).
List of Subjects
14 CFR Part 1
Air transportation.
14 CFR Part 23
Aviation Safety, Signs, Symbols, Aircraft.
The Proposed Amendments
In consideration of the foregoing, the Federal Aviation
Administration proposes to amend Chapter I of Title 14, Code of Federal
Regulations, as follows:
PART 1--DEFINITIONS AND ABBREVIATIONS
1. The authority citation for part 1 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
2. Revise the definitions of ``Rated takeoff power'' and ``Rated
takeoff thrust'' and add the definitions of ``Turbine engine'',
``Turbojet engine'', and ``Turboprop engine'' in alphabetical order in
Sec. 1.1 to read as follows:
Sec. 1.1 General definitions.
* * * * *
[[Page 41539]]
Rated takeoff power, with respect to reciprocating, turbopropeller,
and turboshaft engine type certification, means the approved brake
horsepower that is developed statically under standard sea level
conditions, within the engine operating limitations established under
part 33 of this chapter, and limited in use--
(1) To periods of not more than 5 minutes for takeoff operations
with reciprocating, turbopropeller, and turboshaft engines; and
(2) When specifically requested by the engine manufacturer, to
periods of not more than 10 minutes for one-engine-inoperative takeoff
operations with turbopropeller engines.
Rated takeoff thrust, with respect to turbojet engine type
certification, means the approved turbojet thrust that is developed
statically under standard sea level conditions, without fluid injection
and without the burning of fuel in a separate combustion chamber,
within the engine operating limitations established under part 33 of
this chapter, and limited in use--
(1) To periods of not more than 5 minutes for takeoff operations;
and
(2) When specifically requested by the engine manufacturer, to
periods of not more than 10 minutes for one-engine-inoperative takeoff
operations.
* * * * *
Turbine engine, with respect to part 23 airplane type
certification, consists of an air compressor, a combustion section, and
a turbine. Thrust is produced by increasing the velocity of the air
flowing through the engine.
Turbojet engine, with respect to part 23 airplane type
certification, is a turbine engine which produces its thrust entirely
by accelerating the air through the engine.
Turboprop engine, with respect to part 23 airplane type
certification, is a turbine engine which drives a propeller through a
reduction gearing arrangement. Most of the energy in the exhaust gases
is converted into torque, rather than using its acceleration to drive
the airplane.
* * * * *
PART 23--AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND
COMMUTER CATEGORY AIRPLANES
3. The authority citation for part 23 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701-44702, 44704.
4. Amend Sec. 23.3 by revising the first sentence in paragraph (d)
to read as follows:
Sec. 23.3 Airplane categories.
* * * * *
(d) The commuter category is limited to multiengine airplanes that
have a seating configuration, excluding pilot seats, of 19 or less, and
a maximum certificated takeoff weight of 19,000 pounds or less. * * *
* * * * *
5. Amend Sec. 23.45 by revising the introductory text of paragraph
(h) to read as follows:
Sec. 23.45 General.
* * * * *
(h) For multiengine turbojet powered airplanes over 6,000 pounds in
the normal, utility, and acrobatic category and commuter category
airplanes the following also apply:
* * * * *
6. Amend Sec. 23.49 by revising the section heading and the
introductory text of paragraphs (a) and (c) to read as follows:
Sec. 23.49 Stalling speed.
(a) VSO (maximum landing flap configuration) and
VS1 are the stalling speeds or the minimum steady flight
speeds, in knots (CAS), at which the airplane is controllable with--
* * *
(c) Except as provided in paragraph (d) of this section,
VSO at maximum weight may not exceed 61 knots for--
* * * * *
7. Amend Sec. 23.51 by revising paragraph (b)(1) introductory text
and paragraph (c) introductory text to read as follows:
Sec. 23.51 Takeoff speeds.
* * * * *
(b) * * *
(1) For multiengine airplanes, the highest of--
* * *
(c) For normal, utility, and acrobatic category multiengine
turbojet airplanes of more than 6,000 pounds maximum weight and
commuter category airplanes, the following apply:
* * * * *
8. Amend Sec. 23.53 by revising paragraph (c) to read as follows:
Sec. 23.53 Takeoff performance.
* * * * *
(c) For normal, utility, and acrobatic category multiengine
turbojet airplanes of more than 6,000 pounds maximum weight and
commuter category airplanes, takeoff performance, as required by
Sec. Sec. 23.55 through 23.59, must be determined with the operating
engine(s) within approved operating limitations.
9. Amend Sec. 23.55 by revising the introductory text to read as
follows:
Sec. 23.55 Accelerate-stop distance.
For normal, utility, and acrobatic category multiengine turbojet
airplanes of more than 6,000 pounds maximum weight and commuter
category airplanes, the accelerate-stop distance must be determined as
follows:
* * * * *
10. Amend Sec. 23.57 by revising the introductory text to read as
follows:
Sec. 23.57 Takeoff path.
For normal, utility, and acrobatic category multiengine turbojet
airplanes of more than 6,000 pounds maximum weight and commuter
category airplanes, the takeoff path is as follows:
* * * * *
11. Amend Sec. 23.59 by revising the introductory text to read as
follows:
Sec. 23.59 Takeoff distance and takeoff run.
For normal, utility, and acrobatic category multiengine turbojet
airplanes of more than 6,000 pounds maximum weight and commuter
category airplanes, the takeoff distance and, at the option of the
applicant, the takeoff run, must be determined.
* * * * *
12. Amend Sec. 23.61 by revising the introductory text to read as
follows:
Sec. 23.61 Takeoff flight path.
For normal, utility, and acrobatic category multiengine turbojet
airplanes of more than 6,000 pounds maximum weight and commuter
category airplanes, the takeoff flight path must be determined as
follows:
* * * * *
13. Amend Sec. 23.63 by revising the introductory text of
paragraphs (c) and (d) to read as follows:
Sec. 23.63 Climb: General.
* * * * *
(c) For reciprocating engine-powered airplanes of more than 6,000
pounds maximum weight, single-engine turbines, and multiengine turbine
airplanes of 6,000 pounds or less maximum weight in the normal,
utility, and acrobatic category, compliance must be shown at weights as
a function of airport altitude and ambient temperature, within the
operational limits established for takeoff and landing, respectively,
with--
* * * * *
(d) For multiengine turbine airplanes over 6,000 pounds maximum
weight in the normal, utility, and acrobatic category and commuter
category airplanes, compliance must be shown at weights as a function
of airport altitude
[[Page 41540]]
and ambient temperature within the operational limits established for
takeoff and landing, respectively, with--
* * * * *
14. Amend Sec. 23.67 by:
a. Revising paragraph (b) introductory text and (b)(1) introductory
text;
b. Redesignating paragraph (c) as paragraph (d)
c. Revising newly redesignated paragraph (d) introductory text,
paragraph (d)(2) introductory text, paragraph (d)(3) introductory text,
and paragraph (d)(4) introductory text; and
d. Adding new paragraph (c).
The revisions and addition read as follows:
Sec. 23.67 Climb: One-engine inoperative.
* * * * *
(b) For normal, utility, and acrobatic category reciprocating
engine-powered airplanes of more than 6,000 pounds maximum weight, and
turbopropeller-powered airplanes in the normal, utility, and acrobatic
category--
(1) The steady gradient of climb at an altitude of 400 feet above
the takeoff may be no less than 1 percent with the--
* * * * *
(c) For normal, utility, and acrobatic category turbojet engine-
powered airplanes of 6,000 pounds or less maximum weight--
(1) The steady gradient of climb at an altitude of 400 feet above
the takeoff may be no less than 1.2 percent with the--
(i) Critical engine inoperative;
(ii) Remaining engine(s) at takeoff power;
(iii) Landing gear retracted;
(iv) Wing flaps in the takeoff position(s); and
(v) Climb speed equal to that achieved at 50 feet in the
demonstration of Sec. 23.53.
(2) The steady gradient of climb may not be less than 0.75 percent
at an altitude of 1,500 feet above the takeoff surface, or landing
surface, as appropriate, with the--
(i) Critical engine inoperative:
(ii) Remaining engine(s) at not more than maximum continuous power;
(iii) Landing gear retracted;
(iv) Wing flaps retracted; and
(v) Climb speed not less than 1.2 VS1.
(d) For turbojet powered airplanes over 6,000 pounds maximum weight
in the normal, utility and acrobatic category and commuter category
airplanes, the following apply:
* * * * *
(2) Takeoff; landing gear retracted. The steady gradient of climb
at an altitude of 400 feet above the takeoff surface must be at least
2.0 percent of two-engine airplanes, 2.3 percent for three-engine
airplanes, and 2.6 percent for four-engine airplanes with--
* * * * *
(3) Enroute. The steady gradient of climb at an altitude of 1,500
feet above the takeoff or landing surface, as appropriate, must be at
least 1.2 percent for two-engine airplanes, 1.5 percent for three-
engine airplanes, and 1.7 percent for four-engine airplanes with--
* * * * *
(4) Discontinued approach. The steady gradient of climb at an
altitude of 400 feet above the landing surface must be at least 2.1
percent for two-engine airplanes, 2.4 percent for three-engine
airplanes, and 2.7 percent for four-engine airplanes, with--
* * * * *
15. Revise Sec. 23.73 to read as follows:
Sec. 23.73 Reference landing approach speed.
(a) For normal, utility, and acrobatic category reciprocating
engine-powered airplanes of 6,000 pounds or less maximum weight, the
reference landing approach speed, VREF, may not be less than
the greater of VMC, determined in Sec. 23.149(b) with the
wing flaps in the most extended takeoff position, and 1.3
VS1.
(b) For normal, utility, and acrobatic category turbine powered
airplanes of 6,000 pounds or less maximum weight, turboprops of more
than 6,000 pounds maximum weight, and reciprocating engine-powered
airplanes of more than 6,000 pounds maximum weight, the reference
landing approach speed, VREF, may not be less than the
greater of VMC, determined in Sec. 23.149(c), and 1.3
VS1.
(c) For normal, utility, and acrobatic category turbojet engine-
powered airplanes of more than 6,000 pounds maximum weight and commuter
category airplanes, the reference landing approach speed,
VREF, may not be less than the greater of 1.05
VMC, determined in Sec. 23.149(c), and 1.3 VS1.
16. Amend Sec. 23.77 by revising the introductory text of
paragraphs (b) and (c) to read as follows:
Sec. 23.77 Balked landing.
* * * * *
(b) Each normal, utility, and acrobatic category reciprocating
engine-powered and single engine turbine powered airplane of more than
6,000 pounds maximum weight, and multiengine turbine engine-powered
airplane of 6,000 pounds or less maximum weight in the normal, utility,
and acrobatic category must be able to maintain a steady gradient of
climb of at least 2.5 percent with--
* * * * *
(c) Each normal, utility, and acrobatic multiengine turbine powered
airplane over 6,000 pounds maximum weight and each commuter category
airplane must be able to maintain a steady gradient of climb of at
least 3.2 percent with--
* * * * *
17. Amend Sec. 23.175 by adding a new paragraph (b)(3) to read as
follows:
Sec. 23.175 Demonstration of static longitudinal stability.
* * * * *
(b) * * *
(3) Maximum speed for stability characteristics, VFC/MFC.
VFC/MFC may not be less than a speed midway
between VMO/MMO and VDF/MDF
except that, for altitudes where Mach number is the limiting factor,
MFC need not exceed the Mach number at which effective speed
warning occurs.
* * * * *
18. Amend Sec. 23.177 by revising paragraphs (a), (b), and (d) to
read as follows:
Sec. 23.177 Static directional and lateral stability.
(a)(1) The static directional stability, as shown by the tendency
to recover from a wings level sideslip with the rudder free, must be
positive for any landing gear and flap position appropriate to the
takeoff, climb, cruise, approach, and landing configurations. This must
be shown with symmetrical power up to maximum continuous power, and at
speeds from 1.2 VS1 up to the landing gear or wing flap
operating limit speeds, or VNO or VFC/
MFC, whichever is appropriate.
(2) The angle of sideslip for these tests must be appropriate to
the type of airplane. The rudder pedal force may not reverse at larger
angles of sideslip, up to that at which full rudder is used or a
control force limit in Sec. 23.143 is reached, whichever occurs first,
and at speeds from 1.2 VS1 to VO.
(b)(1) The static lateral stability, as shown by the tendency to
raise the low wing in a sideslip with the aileron controls free, may
not be negative for any landing gear and flap position appropriate to
the takeoff, climb, cruise, approach, and landing configurations. This
must be shown with symmetrical power from idle up to 75 percent of
maximum continuous power at speeds from 1.2 VS1 in the
takeoff configuration(s) and at speeds from 1.3 VS1 in other
configurations, up to the maximum allowable airspeed for the
configuration being investigated, (VFE,
[[Page 41541]]
VLE, VNO, VFC/MFC,
whichever is appropriate) in the takeoff, climb, cruise, descent, and
approach configurations. For the landing configuration, the power must
be that necessary to maintain a 3-degree angle of descent in
coordinated flight.
(2) The static lateral stability may not be negative at 1.2
VS1 in the takeoff configuration, or at 1.3 VS1
in other configurations.
(3) The angle of sideslip for these tests must be appropriate to
the type of airplane, but in no case may the constant heading sideslip
angle be less than that obtainable with a 10 degree bank or, if less,
the maximum bank angle obtainable with full rudder deflection or 150
pound rudder force.
* * * * *
(d)(1) In straight, steady slips at 1.2 VS1 for any
landing gear and flap position appropriate to the takeoff, climb,
cruise, approach, and landing configurations, and for any symmetrical
power conditions up to 50 percent of maximum continuous power, the
aileron and rudder control movements and forces must increase steadily,
but not necessarily in constant proportion, as the angle of sideslip is
increased up to the maximum appropriate to the type of airplane.
(2) At larger slip angles, up to the angle at which the full rudder
or aileron control is used or a control force limit contained in Sec.
23.143 is reached, the aileron and rudder control movements and forces
may not reverse as the angle of sideslip is increased.
(3) Rapid entry into, and recovery from, a maximum sideslip
considered appropriate for the airplane may not result in
uncontrollable flight characteristics.
19. Amend Sec. 23.181 by revising paragraph (b) to read as
follows:
Sec. 23.181 Dynamic stability.
* * * * *
(b) Any combined lateral-directional oscillations (``Dutch roll'')
occurring between the stalling speed and the maximum allowable speed
appropriate to the configuration of the airplane with the primary
controls in both free and fixed position, must be damped to 1/10
amplitude in:
(1) Seven (7) cycles below 18,000 feet, and
(2) Thirteen (13) cycles from 18,000 feet to the certified maximum
altitude.
* * * * *
20. Amend Sec. 23.201 by revising paragraphs (d) and (e) and by
adding a new paragraph (f) to read as follows:
Sec. 23.201 Wings level stall.
* * * * *
(d) During the entry into and the recovery from the maneuver, it
must be possible to prevent more than 15 degrees of roll or yaw by the
normal use of controls except as provided for in paragraph (e) of this
section.
(e) For airplanes approved with a maximum operating altitude above
25,000 feet, during the entry into and the recovery from stalls
performed above 25,000 feet, it must be possible to prevent more than
25 degrees of roll or yaw by the normal use of controls.
(f) Compliance with the requirements of this section must be shown
under the following conditions:
(1) Wing flaps: Retracted, fully extended, and each intermediate
normal operating position, as appropriate for the phase of flight.
(2) Landing gear: Retracted and extended as appropriate for the
altitude.
(3) Cowl flaps: Appropriate to configuration.
(4) Spoilers/speedbrakes: Retracted and extended unless they have
little to no effect at low speeds.
(5) Power:
(i) Power/Thrust off; and
(ii) For reciprocating engine powered airplanes: 75 percent maximum
continuous power. However, if the power-to-weight ratio at 75 percent
of maximum continuous power results in nose-high attitudes exceeding 30
degrees, the test must be carried out with the power required for level
flight in the landing configuration at maximum landing weight and a
speed of 1.4 VSO, except that the power may not be less than
50 percent of maximum continuous power; or
(iii) For turbine engine powered airplanes: The maximum engine
thrust, except that it need not exceed the thrust necessary to maintain
level flight at 1.6 VS1 (where VS1 corresponds to
the stalling speed with flaps in the approach position, the landing
gear retracted, and maximum landing weight).
(6) Trim at 1.5 VS1 or the minimum trim speed, whichever
is higher.
(7) Propeller: Full increase r.p.m. position for the power off
condition.
21. Amend Sec. 23.203 by revising paragraph (c) to read as
follows:
Sec. 23.203 Turning flight and accelerated turning stalls.
* * * * *
(c) Compliance with the requirements of this section must be shown
under the following conditions:
(1) Wings flaps: Retracted, fully extended, and each intermediate
normal operating position as appropriate for the phase of flight.
(2) Landing gear: Retracted and extended as appropriate for the
altitude.
(3) Cowl flaps: Appropriate to configuration.
(4) Spoilers/speedbrakes: Retracted and extended unless they have
little to no effect at low speeds.
(5) Power:
(i) Power/Thrust off; and
(ii) For reciprocating engine powered airplanes: 75 percent maximum
continuous power. However, if the power-to-weight ratio at 75 percent
of maximum continuous power results in nose-high attitudes exceeding 30
degrees, the test may be carried out with the power required for level
flight in the landing configuration at maximum landing weight and a
speed of 1.4 VSO, except that the power may not be less than
50 percent of maximum continuous power; or
(iii) For turbine engine powered airplanes: The maximum engine
thrust, except that it need not exceed the thrust necessary to maintain
level flight at 1.6 VS1 (where VS1 corresponds to
the stalling speed with flaps in the approach position, the landing
gear retracted, and maximum landing weight).
(6) Trim: The airplane trimmed at 1.5 VS1.
(7) Propeller: Full increase rpm position for the power off
condition.
22. Revise Sec. 23.251 to read as follows:
Sec. 23.251 Vibration and buffeting.
(a) There may be no vibration or buffeting severe enough to result
in structural damage, and each part of the airplane must be free from
excessive vibration, under any appropriate speed and power conditions
up to VD/MD, or VDF/MDF for
turbojets. In addition, there may be no buffeting in any normal flight
condition, including configuration changes during cruise, severe enough
to interfere with the satisfactory control of the airplane or cause
excessive fatigue to the flight crew. Stall warning buffeting within
these limits is allowable.
(b) There may be no perceptible buffeting condition in the cruise
configuration in straight flight at any speed up to VMO/
MMO, except stall buffeting, which is allowable.
(c) For airplanes with MD greater than M 0.6 and a
maximum operating altitude greater than 25,000 feet, the positive
maneuvering load factors at which the onset of perceptible buffeting
occurs must be determined with the airplane in the cruise configuration
for the ranges of airspeed or Mach number, weight, and altitude for
which the airplane is to be certificated. The envelopes of load factor,
speed, altitude, and weight must provide a sufficient range of speeds
and load factors for
[[Page 41542]]
normal operations. Probable inadvertent excursions beyond the
boundaries of the buffet onset envelopes may not result in unsafe
conditions.
23. Amend Sec. 23.253 by revising paragraphs (b)(1) and (b)(2),
and by adding a new paragraph (b)(3) to read as follows:
Sec. 23.253 High speed characteristics.
* * * * *
(b) * * *
(1) Exceptional piloting strength or skill;
(2) Exceeding VD/MD, or VDF/
MDF for turbojet, the maximum speed shown under Sec.
23.251, or the structural limitations; and
(3) Buffeting that would impair the pilot's ability to read the
instruments or to control the airplane for recovery.
* * * * *
24. Section 23.255 is added to subpart B to read as follows:
Sec. 23.255 Out of trim characteristics.
For airplanes with an MD greater than M 0.6 and that
incorporate a trimmable horizontal stabilizer, the following
requirements for out-of-trim characteristics apply:
(a) From an initial condition with the airplane trimmed at cruise
speeds up to VMO/MMO, the airplane must have
satisfactory maneuvering stability and controllability with the degree
of out-of-trim in both the airplane nose-up and nose-down directions,
which results from the greater of the following:
(1) A three-second movement of the longitudinal trim system at its
normal rate for the particular flight condition with no aerodynamic
load (or an equivalent degree of trim for airplanes that do not have a
power-operated trim system), except as limited by stops in the trim
system, including those required by Sec. 23.655(b) for adjustable
stabilizers; or
(2) The maximum mis-trim that can be sustained by the autopilot
while maintaining level flight in the high speed cruising condition.
(b) In the out-of-trim condition specified in paragraph (a) of this
section, when the normal acceleration is varied from +l g to the
positive and negative values specified in paragraph (c) of this
section, the following apply:
(1) The stick force versus g curve must have a positive slope at
any speed up to and including VFC/MFC; and
(2) At speeds between VFC/MFC and
VDF/MDF, the direction of the primary
longitudinal control force may not reverse.
(c) Except as provided in paragraphs (d) and (e) of this section,
compliance with the provisions of paragraph (a) of this section must be
demonstrated in flight over the acceleration range as follows:
(1) -1 g to +2.5g; or
(2) 0 g to 2.0g, and extrapolating by an acceptable method to -1g
and +2.5g.
(d) If the procedure set forth in paragraph (c)(2) of this section
is used to demonstrate compliance and marginal conditions exist during
flight test with regard to reversal of primary longitudinal control
force, flight tests must be accomplished from the normal acceleration
at which a marginal condition is found to exist to the applicable limit
specified in paragraph (b)(1) of this section.
(e) During flight tests required by paragraph (a) of this section,
the limit maneuvering load factors, prescribed in Sec. Sec. 23.333(b)
and 23.337, need not be exceeded. In addition, the entry speeds for
flight test demonstrations at normal acceleration values less than 1g
must be limited to the extent necessary to accomplish a recovery
without exceeding VDF/MDF.
(f) In the out-of-trim condition specified in paragraph (a) of this
section, it must be possible from an overspeed condition at
VDF/MDF to produce at least 1.5g for recovery by
applying not more than 125 pounds of longitudinal control force using
either the primary longitudinal control alone or the primary
longitudinal control and the longitudinal trim system. If the
longitudinal trim is used to assist in producing the required load
factor, it must be shown at VDF/MDF that the
longitudinal trim can be actuated in the airplane nose-up direction
with the primary surface loaded to correspond to the least of the
following airplane nose-up control forces:
(1) The maximum control forces expected in service, as specified in
Sec. Sec. 23.301 and 23.397.
(2) The control force required to produce 1.5g.
(3) The control force corresponding to buffeting or other phenomena
of such intensity that it is a strong deterrent to further application
of primary longitudinal control force.
25. Amend Sec. 23.561 by adding new paragraphs (e)(1) and (e)(2)
to read as follows:
Sec. 23.561 General.
* * * * *
(e) * * *
(1) For turbojet engines mounted inside the fuselage, aft of the
cabin, it must be shown by test or analysis that the engine and
attached accessories, and the engine mounting structure--
(i) Can withstand a forward acting static ultimate inertia load
factor of 18.0g plus the maximum takeoff engine thrust; or
(ii) The airplane structure is designed to deflect the engine and
its attached accessories away from the cabin should the engine mounts
fail.
(2) [Reserved]
26. Amend Sec. 23.562 by revising paragraphs (a) introductory
text, (b) introductory text, and (c)(5)(ii) to read as follows:
Sec. 23.562 Emergency landing dynamic conditions.
(a) Each seat/restraint system for use in a normal, utility, or
acrobatic category airplane, or in a commuter category turbojet powered
airplane, must be designed to protect each occupant during an emergency
landing when--
* * * * *
(b) Except for those seat/restraint systems that are required to
meet paragraph (d) of this section, each seat/restraint system for crew
or passenger occupancy in a normal, utility, or acrobatic category
airplane, or in a commuter category turbojet powered airplane, must
successfully complete dynamic tests or be demonstrated by rational
analysis supported by dynamic tests, in accordance with each of the
following conditions. These tests must be conducted with an occupant
simulated by an anthropomorphic test dummy (ATD) defined by 49 CFR part
572, subpart B, or an FAA-approved equivalent, with a nominal weight of
170 pounds and seated in the normal upright position.
* * * * *
(c) * * *
(5) * * *
(ii) The value of HIC is defined as--
[GRAPHIC] [TIFF OMITTED] TP17AU09.000
[[Page 41543]]
Where:
t1 is the initial integration time, expressed in seconds,
t2 is the final integration time, expressed in seconds,
and a(t) is the total acceleration vs. time curve for the head
expressed as a multiple of g (units of gravity).
* * * * *
27. Amend Sec. 23.571 by adding a new paragraph (d) to read as
follows:
Sec. 23.571 Metallic pressurized cabin structures.
* * * * *
(d) If certification for operation above 41,000 feet is requested,
a damage tolerance evaluation of the fuselage pressure boundary per
Sec. 23.573(b) must be conducted and the evaluation must factor in the
environmental requirements of Sec. 23.841.
28. Amend Sec. 23.573 by adding a new paragraph (c) to read as
follows:
Sec. 23.573 Damage tolerance and fatigue evaluation of structure.
* * * * *
(c) If certification for operation above 41,000 feet is requested,
the damage tolerance evaluation of this paragraph for the fuselage
pressure boundary must factor in the requirements of Sec. 23.841.
29. Amend Sec. 23.574 by adding a new paragraph (c) to read as
follows:
Sec. 23.574 Metallic damage tolerance and fatigue evaluation of
commuter category airplanes.
* * * * *
(c) If certification for operation above 41,000 feet is requested,
the damage tolerance evaluation of this paragraph for the fuselage
pressure boundary must factor in the requirements of Sec. 23.841.
30. Amend Sec. 23.629 by revising paragraphs (b)(1), (b)(3),
(b)(4), and (c) to read as follows:
Sec. 23.629 Flutter.
* * * * *
(b) * * *
(1) Proper and adequate attempts to induce flutter have been made
within the speed range up to VD/MD;
* * * * *
(3) A proper margin of damping exists at VD/
MD, or VDF/MDF for turbojet airplanes;
and
(4) As VD/MD (or VDF/
MDF for turbojet airplanes) is approached, there may not be
a large or rapid reduction in damping.
(c) Any rational analysis used to predict freedom from flutter,
control reversal and divergence must cover all speeds up to 1.2
VD/MD, or 1.2 VDF/MDF for
turbojet airplanes.
* * * * *
31. Amend Sec. 23.703 by revising the introductory text and
paragraph (b) to read as follows:
Sec. 23.703 Takeoff warning system.
For all airplanes with a maximum weight more than 6,000 pounds and
all turbojet airplanes, unless it can be shown that a lift or
longitudinal trim device that affects the takeoff performance of the
airplane would not give an unsafe takeoff configuration when selected
out of an approved takeoff position, a takeoff warning system must be
installed and meet the following requirements:
* * * * *
(b) For the purpose of this section, an unsafe takeoff
configuration is the inability to rotate or the inability to prevent an
immediate stall after rotation.
32. Amend Sec. 23.735 by revising paragraph (e) to read as
follows:
Sec. 23.735 Brakes.
* * * * *
(e) For airplanes required to meet Sec. 23.55, the rejected
takeoff brake kinetic energy capacity rating of each main wheel brake
assembly may not be less than the kinetic energy absorption
requirements determined under either of the following methods--
(1) The brake kinetic energy absorption requirements must be based
on a conservative rational analysis of the sequence of events expected
during a rejected takeoff at the design takeoff weight.
(2) Instead of a rational analysis, the kinetic energy absorption
requirements for each main wheel brake assembly may be derived from the
following formula--
KE = 0.0443 WV\2\/N
Where:
KE = Kinetic energy per wheel (ft.-lbs.);
W = Design takeoff weight (lbs.);
V = Ground speed, in knots, associated with the maximum value of
V1 selected in accordance with Sec. 23.51(c)(1);
N = Number of main wheels with brakes.
33. Amend Sec. 23.777 by revising paragraph (d) to read as
follows:
Sec. 23.777 Cockpit controls.
* * * * *
(d) When separate and distinct control levers are co-located (such
as located together on the pedestal), the control location order from
left to right must be power (thrust) lever, propeller (rpm control),
and mixture control (condition lever and fuel cut-off for turbine-
powered airplanes). Power (thrust) levers must be at least one inch
higher or longer than propeller (rpm control) or mixture controls to
make them more prominent. Carburetor heat or alternate air control must
be to the left of the throttle or at least eight inches from the
mixture control when located other than on a pedestal. Carburetor heat
or alternate air control, when located on a pedestal, must be aft or
below the power (thrust) lever. Supercharger controls must be located
below or aft of the propeller controls. Airplanes with tandem seating
or single-place airplanes may utilize control locations on the left
side of the cabin compartment; however, location order from left to
right must be power (thrust) lever, propeller (rpm control), and
mixture control.
* * * * *
34. Amend Sec. 23.807 by adding a new paragraph (e)(3) to read as
follows:
Sec. 23.807 Emergency exits.
* * * * *
(e) * * *
(3) In lieu of paragraph (e)(2) of this section, if any side exit
or exits cannot be above the waterline, a device may be placed at each
of such exit(s) prior to ditching. This device must slow the inflow of
water when such exit(s) is opened with the airplane in a ditching
emergency. For commuter category airplanes, the clear opening of such
exit or exits must meet the requirements defined in paragraph (d) of
this section.
35. Amend Sec. 23.831 by adding paragraphs (c) and (d) to read as
follows:
Sec. 23.831 Ventilation.
* * * * *
(c) For turbojet powered pressurized airplanes, under normal
operating conditions and in the event of any probable failure
conditions of any system which would adversely affect the ventilating
air, the ventilation system must provide reasonable passenger comfort.
The ventilation system must also provide a sufficient amount of
uncontaminated air to enable the crew members to perform their duties
without undue discomfort or fatigue and to provide reasonable passenger
comfort. For normal operating conditions, the ventilation system must
be designed to provide each occupant with at least 0.55 pounds of fresh
air per minute. In the event of the loss of one source of fresh air,
the supply of fresh airflow must not be less than 0.4 pounds per minute
for any period exceeding five minutes.
(d) Other probable and improbable Environmental Control System
failure conditions that adversely affect the passenger and crew
compartment environmental conditions may not affect crew performance so
as to result in a hazardous condition, and no occupant shall sustain
permanent physiological harm.
[[Page 41544]]
36. Amend Sec. 23.841 by revising paragraphs (a) and (b)(6), and
by adding paragraphs (c), (d), and (e) to read as follows:
Sec. 23.841 Pressurized cabins.
(a) If certification for operation above 25,000 feet is requested,
the airplane must be able to maintain a cabin pressure altitude of not
more than 15,000 feet, in the event of any probable failure condition
in the pressurization system. During the decompression, the cabin
altitude shall not exceed 15,000 feet for more than 10 seconds and
25,000 feet for any duration.
(b) * * *
(6) Warning indication at the pilot station to indicate when the
safe or preset pressure differential is exceeded and when a cabin
pressure altitude of 10,000 feet is exceeded. The 10,000 foot cabin
altitude warning may be increased up to 15,000 feet for operations from
high altitude airfields (10,000 to 15,000 feet) provided:
(i) The landing or the take off modes (normal or high altitude) are
clearly indicated to the flight crew.
(ii) Selection of normal or high altitude airfield mode requires no
crew action beyond normal pressurization system operation.
(iii) The pressurization system is designed to ensure cabin
altitude does not exceed 10,000 feet when in flight above flight level
(FL) 250.
(iv) The pressurization system and cabin altitude warning system is
designed to ensure cabin altitude warning at 10,000 feet when in flight
above FL250.
* * * * *
(c) If certification for operation above 41,000 feet and not more
than 45,000 feet is requested,
(1) The airplane must prevent cabin pressure altitude from
exceeding the following after decompression from any probable
pressurization system failure in conjunction with any undetected,
latent pressurization system failure condition:
(i) If depressurization analysis shows that the cabin altitude does
not exceed 25,000 feet, the pressurization system must prevent the
cabin altitude from exceeding the cabin altitude-time history shown in
Figure 1 of this section.
(ii) Maximum cabin altitude is limited to 30,000 feet. If cabin
altitude exceeds 25,000 feet, the maximum time the cabin altitude may
exceed 25,000 feet is 2 minutes; time starting when the cabin altitude
exceeds 25,000 feet and ending when it returns to 25,000 feet.
(2) The airplane must prevent cabin pressure altitude from
exceeding the following after decompression from any single
pressurization system failure in conjunction with any probable fuselage
damage:
(i) If depressurization analysis shows that the cabin altitude does
not exceed 37,000 feet, the pressurization system must prevent the
cabin altitude from exceeding the cabin altitude-time history shown in
Figure 2 of this section.
(ii) Maximum cabin altitude is limited to 40,000 feet. If cabin
altitude exceeds 37,000 feet, the maximum time the cabin altitude may
exceed 25,000 feet is 2 minutes; time starting when the cabin altitude
exceeds 25,000 feet and ending when it returns to 25,000 feet.
(3) In showing compliance with paragraphs (c)(1) and (c)(2) of this
section, it may be assumed that an emergency descent is made by an
approved emergency procedure. A 17-second crew recognition and reaction
time must be applied between cabin altitude warning and the initiation
of an emergency descent. Fuselage structure, engine and system failures
are to be considered in evaluating the cabin decompression.
[GRAPHIC] [TIFF OMITTED] TP17AU09.001
Note: For Figure 1, time starts at the moment cabin altitude
exceeds 10,000 feet during decompression.
[[Page 41545]]
[GRAPHIC] [TIFF OMITTED] TP17AU09.002
Note: For Figure 2, time starts at the moment cabin altitude
exceeds 10,000 feet during decompression.
(d) If certification for operation above 45,000 feet and not more
than 51,000 feet is requested--
(1) Pressurized cabins must be equipped to provide a cabin pressure
altitude of not more than 8,000 feet at the maximum operating altitude
of the airplane under normal operating conditions.
(2) The airplane must prevent cabin pressure altitude from
exceeding the following after decompression from any failure condition
not shown to be extremely improbable:
(i) Twenty-five thousand (25,000) feet for more than 2 minutes, or
(ii) Forty thousand (40,000) feet for any duration.
(3) Fuselage structure, engine and system failures are to be
considered in evaluating the cabin decompression.
(4) In addition to the cabin altitude indicating means in (b)(6) of
this section, an aural or visual signal must be provided to warn the
flight crew when the cabin pressure altitude exceeds 10,000 feet.
(5) The sensing system and pressure sensors necessary to meet the
requirements of (b)(5), (b)(6), and (d)(4) of this section and Sec.
23.1447(e), must, in the event of low cabin pressure, actuate the
required warning and automatic presentation devices without any delay
that would significantly increase the hazards resulting from
decompression.
(e) If certification for operation above 41,000 feet is requested,
additional damage-tolerance requirements are necessary to prevent
fatigue damage that could result in a loss of pressure that exceeds the
requirements of paragraphs (c) and (d) of this section. Sufficient full
scale fatigue test evidence must be provided to demonstrate that this
type of pressure loss due to fatigue cracking will not occur within the
Limit of Validity of the Maintenance program for the airplane. In
addition, a damage tolerance evaluation of the fuselage pressure
boundary must be performed assuming visually detectable cracks and the
maximum damage size for which the requirements of paragraphs (c) and
(d) of this section can be met. Based on this evaluation, inspections
or other procedures must be established and included in the Limitations
Section of the Instructions for Continued Airworthiness required by
Sec. 23.1529.
37. Amend Sec. 23.853 by revising paragraph (d)(2) to read as
follows:
Sec. 23.853 Passenger and crew compartment interiors.
* * * * *
(d) * * *
(2) Lavatories must have ``No Smoking'' or ``No Smoking in
Lavatory'' placards located conspicuously on each side of the entry
door.
* * * * *
38. Add a new Sec. 23.856 to read as follows:
Sec. 23.856 Thermal/Acoustic insulation materials.
Thermal/acoustic insulation material installed in the fuselage must
meet the flame propagation test requirements of part II of Appendix F
to this part, or other approved equivalent test requirements. This
requirement does not apply to ``small parts,'' as defined in part I of
Appendix F of this part.
39. Amend Sec. 23.903 by revising paragraph (b)(2) to read as
follows:
Sec. 23.903 Engines.
* * * * *
(b) * * *
(2) For engines embedded in the fuselage behind the cabin, the
effects of a fan exiting forward of the inlet case (fan disconnect)
must be addressed, the passengers must be protected, and the airplane
must have the ability to maintain controlled flight and landing.
* * * * *
40. Amend Sec. 23.1141 by adding a new paragraph (h) to read as
follows:
Sec. 23.1141 Powerplant controls: General.
* * * * *
(h) Electronic engine control system installations must meet the
requirements of Sec. 23.1309.
41. Amend Sec. 23.1165 by revising paragraph (f) to read as
follows:
Sec. 23.1165 Engine ignition systems.
* * * * *
(f) In addition, for commuter category airplanes, each turbine
engine ignition system must be an essential electrical load.
42. Amend Sec. 23.1193 by revising paragraph (g) to read as
follows:
Sec. 23.1193 Cowling and nacelle.
* * * * *
(g) In addition, for all turbojet airplanes and commuter category
airplanes, the airplane must be designed so that no fire originating in
any engine compartment can enter, either through openings or by burn
through, any other region where it would create additional hazards.
43. Amend Sec. 23.1195 by revising the introductory text of
paragraph (a) and by revising paragraph (a)(2) to read as follows:
[[Page 41546]]
Sec. 23.1195 Fire extinguishing systems.
(a) For all turbojet airplanes and commuter category airplanes,
fire extinguishing systems must be installed and compliance shown with
the following:
* * * * *
(2) The fire extinguishing system, the quantity of the
extinguishing agent, the rate of discharge, and the discharge
distribution must be adequate to extinguish fires. An individual ``one
shot'' system may be used, except for engine(s) embedded in the
fuselage, where a ``two-shot'' system is required.
* * * * *
44. Amend Sec. 23.1197 by revising the introductory text to read
as follows:
Sec. 23.1197 Fire extinguishing agents.
For all turbojet airplanes and commuter category airplanes, the
following applies:
* * * * *
45. Amend Sec. 23.1199 by revising the introductory text to read
as follows:
Sec. 23.1199 Extinguishing agent containers.
For all turbojet airplanes and commuter category airplanes, the
following applies:
* * * * *
46. Amend Sec. 23.1201 by revising the introductory text to read
as follows:
Sec. 23.1201 Fire extinguishing systems materials.
For all turbojet airplanes and commuter category airplanes, the
following apply:
* * * * *
47. Revise Sec. 23.1301 by revising paragraphs (b) and (c) and by
removing paragraph (d) to read as follows:
Sec. 23.1301 Function and installation.
* * * * *
(b) Be labeled as to its identification, function, or operating
limitations, or any applicable combination of these factors; and
(c) Be installed according to limitations specified for that
equipment.
48. Amend Sec. 23.1303 by revising paragraph (c) to read as
follows:
Sec. 23.1303 Flight and navigation instruments.
* * * * *
(c) A magnetic direction indicator.
* * * * *
49. Amend Sec. 23.1305 by adding a new paragraph (f) to read as
follows:
Sec. 23.1305 Powerplant instruments.
* * * * *
(f) Powerplant indicators must either provide trend or rate-of-
change information, or have the ability to:
(1) Allow the pilot to assess necessary trend information quickly,
including if and when this information is needed during engine restart;
(2) Allow the pilot to assess how close the indicated parameter is
relative to a limit;
(3) Forewarn the pilot before the parameter reaches an operating
limit; and
(4) For multiengine airplanes, allow the pilot to quickly and
accurately compare engine-to-engine data.
50. Revise Sec. 23.1307 to read as follows:
Sec. 23.1307 Miscellaneous equipment.
The equipment necessary for an airplane to operate at the maximum
operating altitude and in the kinds of operations (e.g., part 91, part
135) and meteorological conditions for which certification is requested
and is approved in accordance with Sec. 23.1559 must be included in
the type design.
51. Revise Sec. 23.1309 to read as follows:
Sec. 23.1309 Equipment, systems, and installations.
The requirements of this section, except as identified below, are
applicable, in addition to specific design requirements of part 23, to
any equipment or system as installed in the airplane. This section is a
regulation of general requirements. It does not supersede any specific
requirements contained in another section of part 23. This section
should be used to determine software and hardware development assurance
levels. This section does not apply to the performance, flight
characteristics requirements of subpart B of this part, and structural
loads and strength requirements of subparts C and D of this part, but
it does apply to any system on which compliance with the requirements
of subparts B, C, D, and E of this part are based. The flight structure
such as wing, empennage, control surfaces and their simple, or simple
and conventional systems, the fuselage, engine mounting, and landing
gear and their related primary attachments are excluded. For example,
it does not apply to an airplane's inherent stall characteristics or
their evaluation of Sec. 23.201, but it does apply to a stick pusher
(stall barrier) system installed to attain compliance with Sec.
23.201.
(a) The airplane equipment and systems must be designed and
installed so that:
(1) Those required for type certification or by operating rules, or
whose improper functioning would reduce safety, perform as intended
under the airplane operating and environmental conditions, including
radio frequency energy and the effects (both direct and indirect) of
lightning strikes.
(2) Those required for type certification or by operating rules and
other equipment and systems do not adversely affect the safety of the
airplane or its occupants, or the proper functioning of those covered
by paragraph (a)(1) of this section.
(3) For minor, major, hazardous, or catastrophic failure
condition(s), the results of certification testing must not be
inconsistent with the results of the safety analysis process.
(b) The airplane systems and associated components for the
appropriate classes of airplane, considered separately and in relation
to other systems, must be designed and installed so that:
(1) Each catastrophic failure condition is extremely improbable and
does not result from a single failure;
(2) Each hazardous failure condition is extremely remote;
(3) Each major failure condition is remote; and
(4) Each failure condition meets the relationship among airplane
classes, probabilities, severity of failure condition(s), and software
and complex hardware development assurance levels shown in Appendix K
of this part.
(5) Compliance with the requirements of paragraph (b)(2) of this
section may be shown by analysis and, where necessary, by appropriate
ground, flight, or simulator tests. The analysis must consider--
(i) Possible modes of failure, including malfunctions and damage
from external sources;
(ii) The probability of multiple failures and the probability of
undetected faults;
(iii) The resulting effects of the airplane and occupants,
considering the stage of flight and operating conditions; and
(iv) The crew warning cues, corrective action required, and the
crew's capability of determining faults.
(c) Functional failure condition(s) that are classified as minor do
not require a quantitative analysis, but verification by a design and
installation appraisal is required.
(d) Systems with major failure condition(s)--
(1) May be verified by a qualitative analysis, if the systems are
simple, simple and conventional, or conventional and redundant.
(2) Must be verified by a qualitative and quantitative analysis, if
the systems
[[Page 41547]]
do not meet the condition(s) prescribed in paragraph (d)(1) of this
section.
(e) Systems with hazardous or catastrophic failure condition(s)--
(1) May be verified by a qualitative and quantitative analysis, if
the systems are simple and conventional.
(2) Must be verified by a qualitative and quantitative analysis if
the systems are not simple and conventional.
(f) Information concerning an unsafe system operating condition(s)
must be provided to the crew to enable them to take appropriate
corrective action. A warning indication must be provided if immediate
corrective action is required. Systems and controls, including
indications and annunciations must be designed to minimize crew errors,
which could create additional hazards.
52. Add a new Sec. 23.1310 to read as follows:
Sec. 23.1310 Power source capacity and distribution.
(a) Each item of equipment, each system, and each installation
whose functioning is required by this chapter and that requires a power
supply is an ``essential load'' on the power supply. The power sources
and the system must be able to supply the following power loads in
probable operating combinations and for probable durations:
(1) Loads connected to the power distribution system with the
system functioning normally.
(2) Essential loads after failure of--
(i) Any one engine on two-engine airplanes, or
(ii) Any two engines on an airplane with three or more engines, or
(iii) Any power converter or energy storage device.
(3) Essential loads for which an alternate source of power is
required, as applicable, by the operating rules of this chapter, after
any failure or malfunction in any one power supply system, distribution
system, or other utilization system.
(b) In determining compliance with paragraph (a)(2) of this
section, the power loads may be assumed to be reduced under a
monitoring procedure consistent with safety in the kinds of operations
authorized. Loads not required in controlled flight need not be
considered for the two-engine-inoperative condition on airplanes with
three or more engines.
53. Amend Sec. 23.1311 by revising paragraphs (a)(5), (a)(6),
(a)(7), and paragraph (b) to read as follows:
Sec. 23.1311 Electronic display instrument systems.
(a) * * *
(5) Have an independent magnetic direction indicator and an
independent secondary mechanical altimeter, airspeed indicator, and
attitude instrument or electronic display parameters for the altitude,
airspeed, and attitude that are independent from the airplane's primary
electrical power system. These secondary instruments may be installed
in panel positions that are displaced from the primary positions
specified by Sec. 23.1321(d), but must be located where they meet the
pilot's visibility requirements of Sec. 23.1321(a).
(6) Incorporate sensory cues that provide a quick glance sense of
rate and, when appropriate, trend information to the pilot.
(7) Incorporate equivalent visual displays of the instrument
markings required by Sec. Sec. 23.1541 through 23.1553, or visual
displays that alert the pilot to abnormal operational values or
approaches to established limitation values, for each parameter
required to be displayed by this part.
(b) The electronic display indicators, including their systems and
installations, and considering other airplane systems, must be designed
so that one display of information essential for continued safe flight
and landing will be available within one second to the crew with a
single pilot action or by automatic means for continued safe operation,
after any single failure or probable combination of failures.
* * * * *
54. Amend Sec. 23.1323 by revising paragraph (e) to read as
follows:
Sec. 23.1323 Airspeed indicating system.
* * * * *
(e) In addition, for normal, utility, and acrobatic category
multiengine turbojet airplanes of more than 6,000 pounds maximum weight
and commuter category airplanes, each system must be calibrated to
determine the system error during the accelerate-takeoff ground run.
The ground run calibration must be determined--
(1) From 0.8 of the minimum value of V1 to the maximum
value of V2, considering the approved ranges of altitude and
weight, and
(2) The ground run calibration must be determined assuming an
engine failure at the minimum value of V1.
* * * * *
55. Amend Sec. 23.1331 by revising paragraph (c) to read as
follows:
Sec. 23.1331 Instruments using a power source.
* * * * *
(c) For certification for Instrument Flight Rules (IFR) operations
and for the heading, altitude, airspeed, and attitude, there must be at
least:
(1) Two independent sources of power (not driven by the same engine
on multiengine airplanes), and a manual or an automatic means to select
each power source; or
(2) An additional display of parameters for heading, altitude,
airspeed, and attitude that is independent from the airplane's primary
electrical power system.
56. Amend Sec. 23.1353 by revising paragraph (h) to read as
follows:
Sec. 23.1353 Storage battery design and installation.
* * * * *
(h) In the event of a complete loss of the primary electrical power
generating system, the battery must be capable of providing electrical
power to those loads that are essential to continued safe flight and
landing for:
(1) At least 30 minutes for airplanes that are certificated with a
maximum altitude of 25,000 feet or less, and
(2) At least 60 minutes for airplanes that are certificated with a
maximum altitude over 25,000 feet.
57. Revise Sec. 23.1443 to read as follows:
Sec. 23.1443 Minimum mass flow of supplemental oxygen.
(a) If the airplane is to be certified above 40,000 feet, a
continuous flow oxygen system must be provided for each passenger and
crewmember.
(b) If continuous flow oxygen equipment is installed, an applicant
must show compliance with the requirements of either paragraphs (b)(1)
and (b)(2) or paragraph (b)(3) of this section:
(1) For each passenger, the minimum mass flow of supplemental
oxygen required at various cabin pressure altitudes may not be less
than the flow required to maintain, during inspiration and while using
the oxygen equipment (including masks) provided, the following mean
tracheal oxygen partial pressures:
(i) At cabin pressure altitudes above 10,000 feet up to and
including 18,500 feet, a mean tracheal oxygen partial pressure of 100mm
Hg when breathing 15 liters per minute, Body Temperature, Pressure,
Saturated (BTPS) and with a tidal volume of 700cc with a constant time
interval between respirations.
(ii) At cabin pressure altitudes above 18,500 feet up to and
including 40,000 feet, a mean tracheal oxygen partial pressure of
83.8mm Hg when breathing 30 liters per minute, BTPS, and with a tidal
volume of 1,100cc with a constant time interval between respirations.
[[Page 41548]]
[GRAPHIC] [TIFF OMITTED] TP17AU09.003
(2) For each flight crewmember, the minimum mass flow may not be
less than the flow required to maintain, during inspiration, a mean
tracheal oxygen partial pressure of 149mm Hg when breathing 15 liters
per minute, BTPS, and with a maximum tidal volume of 700cc with a
constant time interval between respirations.
(3) The minimum mass flow of supplemental oxygen supplied for each
user must be at a rate not less than that shown in the following figure
for each altitude up to and including the maximum operating altitude of
the airplane.
(c) If demand equipment is installed for use by flight crewmembers,
the minimum mass flow of supplemental oxygen required for each flight
crewmember may not be less than the flow required to maintain, during
inspiration, a mean tracheal oxygen partial pressure of 122mm Hg up to
and including a cabin pressure altitude of 35,000 feet, and 95 percent
oxygen between cabin pressure altitudes of 35,000 and 40,000 feet, when
breathing 20 liters per minutes BTPS. In addition, there must be means
to allow the crew to use undiluted oxygen at their discretion.
(d) If first-aid oxygen equipment is installed, the minimum mass
flow of oxygen to each user may not be less than 4 liters per minute,
STPD. However, there may be a means to decrease this flow to not less
than 2 liters per minute, STPD, at any cabin altitude. The quantity of
oxygen required is based upon an average flow rate of 3 liters per
minute per person for whom first-aid oxygen is required.
(e) As used in this section:
(1) BTPS means Body Temperature, and Pressure, Saturated (which is
37 [deg]C, and the ambient pressure to which the body is exposed, minus
47mm Hg, which is the tracheal pressure displaced by water vapor
pressure when the breathed air becomes saturated with water vapor at 37
[deg]C).
(2) STPD means Standard Temperature and Pressure, Dry (which is 0
[deg]C at 760mm Hg with no water vapor).
58. Amend Sec. 23.1445 by adding a new paragraph (c) to read as
follows:
Sec. 23.1445 Oxygen distribution system.
* * * * *
(c) If the flight crew and passengers share a common source of
oxygen, a means to separately reserve the minimum supply required by
the flight crew must be provided.
59. Amend Sec. 23.1447 by adding a new paragraph (g) to read as
follows:
Sec. 23.1447 Equipment standards for oxygen dispensing units.
* * * * *
(g) If the airplane is to be certified for operation above 40,000
feet, a quick-donning oxygen mask system, with a pressure demand, mask
mounted regulator must be provided for the flight crew. This dispensing
unit must be immediately available to the flight crew when seated at
their station and installed so that it:
(1) Can be placed on the face from its ready position, properly
secured, sealed, and supplying oxygen upon demand, with one hand,
within five seconds and without disturbing eyeglasses or causing delay
in proceeding with emergency duties, and
(2) Allows, while in place, the performance of normal communication
functions.
60. Amend Sec. 23.1505 by revising paragraph (c) to read as
follows:
Sec. 23.1505 Airspeed limitations.
* * * * *
(c) Paragraphs (a) and (b) of this section do not apply to turbine
airplanes or the airplanes for which a design diving speed
VD/MD is established under Sec. 23.335(b)(4).
For those airplanes, a maximum operating limit speed (VMO/
MMO airspeed or Mach number, whichever is critical at a
particular altitude) must be established as a speed that may not be
deliberately exceeded in any regime of flight (climb, cruise, or
descent) unless a higher speed is authorized for flight test or pilot
training operations. VMO/MMO must be established
so that it is not greater than the design cruising speed VC/
MC and so that it is sufficiently below VD/
MD, or VDF/MDF for turbojets, and the
maximum speed shown under Sec. 23.251 to make it highly improbable
that the latter speeds will be inadvertently exceeded in operations.
The speed margin between VMO/MMO and
VD/MD,
[[Page 41549]]
or VDF/MDF for turbojets, may not be less than
that determined under Sec. 23.335(b), or the speed margin found
necessary in the flight tests conducted under Sec. 23.253.
61. Revise Sec. 23.1525 to read as follows:
Sec. 23.1525 Kinds of operation.
The kinds of operation authorized (e.g., VFR, IFR, day, night, part
91, part 135) and the meteorological conditions (e.g., icing) to which
the operation of the airplane is limited or from which it is
prohibited, must be established appropriate to the installed equipment.
62. Amend Sec. 23.1545 by revising paragraph (d) to read as
follows:
Sec. 23.1545 Airspeed indicator.
* * * * *
(d) Paragraphs (b)(1) through (b)(4) and paragraph (c) of this
section do not apply to airplanes for which a maximum operating speed
VMO/MMO is established under Sec. 23.1505(c).
For those airplanes, there must either be a maximum allowable airspeed
indication showing the variation of VMO/MMO with
altitude or compressibility limitations (as appropriate), or a radial
red line marking for VMO/MMO must be made at the
lowest value of VMO/MMO established for any
altitude up to the maximum operating altitude for the airplane.
63. Amend Sec. 23.1555 by adding a new paragraph (d)(3) to read as
follows:
Sec. 23.1555 Control markings.
* * * * *
(d) * * *
(3) For fuel systems having a calibrated fuel quantity indication
system complying with Sec. 23.1337(b)(1) and accurately displaying the
actual quantity of usable fuel in each selectable tank, no fuel
capacity placards outside of the fuel quantity indicator are required.
* * * * *
64. Amend Sec. 23.1559 by adding a new paragraph (d) to read as
follows:
Sec. 23.1559 Operating limitations placard.
* * * * *
(d) The placard(s) required by this section need not be lighted.
65. Amend Sec. 23.1563 by adding a new paragraph (d) to read as
follows:
Sec. 23.1563 Airspeed placards.
* * * * *
(d) The airspeed placard required by this section need not be
lighted if the landing gear operating speed is indicated on the
airspeed indicator or other lighted area such as the landing gear
control and the airspeed indicator has features such as low speed
awareness that provide ample warning prior to VMC.
66. Amend Sec. 23.1567 by adding a new paragraph (e) to read as
follows:
Sec. 23.1567 Flight maneuver placard.
* * * * *
(e) The placards required by this section need not be lighted.
67. Amend Sec. 23.1583 as follows:
a. Revise the introductory text of paragraphs (c)(3) and (c)(4);
b. Redesignate paragraphs (c)(4)(iii) and (c)(4)(iv) as paragraphs
(c)(4)(ii)(A) and (c)(4)(ii)(B); and
c. Revise paragraph (c)(5) introductory text to read as follows:
Sec. 23.1583 Operating limitations.
* * * * *
(c) * * *
(3) For reciprocating engine-powered airplanes of more than 6,000
pounds maximum weight, single-engine turbines, and multiengine turbine
airplanes 6,000 pounds or less maximum weight in the normal, utility,
and acrobatic category, performance operating limitations as follows--
* * * * *
(4) For normal, utility, and acrobatic category multiengine
turbojet powered airplanes over 6,000 pounds and commuter category
airplanes, the maximum takeoff weight for each airport altitude and
ambient temperature within the range selected by the applicant at
which--
* * * * *
(5) For normal, utility, and acrobatic category multiengine
turbojet powered airplanes over 6,000 pounds and commuter category
airplanes, the maximum landing weight for each airport altitude within
the range selected by the applicant at which--
* * * * *
68. Amend Sec. 23.1585 by revising paragraph (f) introductory text
to read as follows:
Sec. 23.1585 Operating procedures.
* * * * *
(f) In addition to paragraphs (a) and (c) of this section, for
normal, utility, and acrobatic category multiengine turbojet powered
airplanes over 6,000 pounds, and commuter category airplanes, the
information must include the following:
* * * * *
69. Amend Sec. 23.1587 by revising paragraph (d) introductory text
to read as follows:
Sec. 23.1587 Performance information.
* * * * *
(d) In addition to paragraph (a) of this section, for normal,
utility, and acrobatic category multiengine turbojet powered airplanes
over 6,000 pounds, and commuter category airplanes, the following
information must be furnished--
* * * * *
70. Amend Appendix F to Part 23 by:
a. Redesignating the existing text as Part I and adding a new Part
I heading;
b. Removing the introductory paragraph; and
c. Adding a new Part II.
The additions read as follows:
APPENDIX F TO PART 23--TEST PROCEDURE
Part I--Acceptable Test Procedure for Self-Extinguishing Materials for
Showing Compliance With Sec. Sec. 23.853, 23.855 and 23.1359
* * * * *
Part II--Test Method To Determine the Flammability and Flame
Propagation Characteristics of Thermal/Acoustic Insulation Materials
Use this test method to evaluate the flammability and flame
propagation characteristics of thermal/acoustic insulation when
exposed to both a radiant heat source and a flame.
(a) Definitions.
``Flame propagation'' means the furthest distance of the
propagation of visible flame towards the far end of the test
specimen, measured from the midpoint of the ignition source flame.
Measure this distance after initially applying the ignition source
and before all flame on the test specimen is extinguished. The
measurement is not a determination of burn length made after the
test.
``Radiant heat source'' means an electric or air propane panel.
``Thermal/acoustic insulation'' means a material or system of
materials used to provide thermal and/or acoustic protection.
Examples include fiberglass or other batting material encapsulated
by a film covering and foams.
``Zero point'' means the point of application of the pilot
burner to the test specimen.
(b) Test apparatus.
[[Page 41550]]
[GRAPHIC] [TIFF OMITTED] TP17AU09.004
(1) Radiant panel test chamber. Conduct tests in a radiant panel
test chamber (see figure F1 above). Place the test chamber under an
exhaust hood to facilitate clearing the chamber of smoke after each
test. The radiant panel test chamber must be an enclosure 55 inches
(1397 mm) long by 19.5 (495 mm) deep by 28 (710 mm) to 30 inches
(maximum) (762 mm) above the test specimen. Insulate the sides,
ends, and top with a fibrous ceramic insulation, such as Kaowool MTM
board. On the front side, provide a 52 by 12-inch (1321 by 305 mm)
draft-free, high-temperature, glass window for viewing the sample
during testing. Place a door below the window to provide access to
the movable specimen platform holder. The bottom of the test chamber
must be a sliding steel platform that has provision for securing the
test specimen holder in a fixed and level position. The chamber must
have an internal chimney with exterior dimensions of 5.1 inches (129
mm) wide, by 16.2 inches (411 mm) deep by 13 inches (330 mm) high at
the opposite end of the chamber from the radiant energy source. The
interior dimensions must be 4.5 inches (114 mm) wide by 15.6 inches
(395 mm) deep. The chimney must extend to the top of the chamber
(see figure F2).
[GRAPHIC] [TIFF OMITTED] TP17AU09.005
(2) Radiant heat source. Mount the radiant heat energy source in
a cast iron frame or equivalent. An electric panel must have six, 3-
inch wide emitter strips. The emitter strips must be perpendicular
to the length of the panel. The panel must have a radiation surface
of 12 \7/8\ by 18 \1/2\ inches (327 by 470 mm). The panel must be
capable of operating at temperatures up to 1300 [deg]F (704 [deg]C).
An air propane panel must be made of a porous refractory material
and have a radiation surface of 12 by 18 inches (305 by 457 mm). The
panel must be capable of operating at temperatures up to 1,500
[deg]F (816 [deg]C). See figures 3a and 3b.
[[Page 41551]]
[GRAPHIC] [TIFF OMITTED] TP17AU09.006
(i) Electric radiant panel. The radiant panel must be 3-phase
and operate at 208 volts. A single-phase, 240 volt panel is also
acceptable. Use a solid-state power controller and microprocessor-
based controller to set the electric panel operating parameters.
(ii) Gas radiant panel. Use propane (liquid petroleum gas--2.1
UN 1075) for the radiant panel fuel. The panel fuel system must
consist of a venturi-type aspirator for mixing gas and air at
approximately atmospheric pressure. Provide suitable instrumentation
for monitoring and controlling the flow of fuel and air to the
panel. Include an air flow gauge, an air flow regulator, and a gas
pressure gauge.
(iii) Radiant panel placement. Mount the panel in the chamber at
30 degrees to the horizontal specimen plane, and 7\1/2\ inches above
the zero point of the specimen.
(3) Specimen holding system.
(i) The sliding platform serves as the housing for test specimen
placement. Brackets may be attached (via wing nuts) to the top lip
of the platform in order to accommodate various thicknesses of test
specimens. Place the test specimens on a sheet of Kaowool MTM board
or 1260 Standard Board (manufactured by Thermal Ceramics and
available in Europe), or equivalent, either resting on the bottom
lip of the sliding platform or on the base of the brackets. It may
be necessary to use multiple sheets of material based on the
thickness of the test specimen (to meet the sample height
requirement). Typically, these non-combustible sheets of material
are available in \1/4\ inch (6 mm) thicknesses. See figure F4. A
sliding platform that is deeper than the 2-
[[Page 41552]]
inch (50.8 mm) platform shown in figure F4 is also acceptable as
long as the sample height requirement is met.
[GRAPHIC] [TIFF OMITTED] TP17AU09.007
(ii) Attach a \1/2\ inch (13 mm) piece of Kaowool MTM board or
other high temperature material measuring 41\1/2\ by 8\1/4\ inches
(1054 by 210 mm) to the back of the platform. This board serves as a
heat retainer and protects the test specimen from excessive
preheating. The height of this board must not impede the sliding
platform movement (in and out of the test chamber). If the platform
has been fabricated such that the back side of the platform is high
enough to prevent excess preheating of the specimen when the sliding
platform is out, a retainer board is not necessary.
(iii) Place the test specimen horizontally on the non-
combustible board(s). Place a steel retaining/securing frame
fabricated of mild steel, having a thickness of \1/8\ inch (3.2 mm)
and overall dimensions of 23 by 13\1/8\ inches (584 by 333 mm) with
a specimen opening of 19 by 10\3/4\ inches (483 by 273 mm) over the
test specimen. The front, back, and right portions of the top flange
of the frame must rest on the top of the sliding platform, and the
bottom flanges must pinch all 4 sides of the test specimen. The
right bottom flange must be flush with the sliding platform. See
figure F5.
[GRAPHIC] [TIFF OMITTED] TP17AU09.008
[[Page 41553]]
(4) Pilot Burner. The pilot burner used to ignite the specimen
must be a BernzomaticTM commercial propane venturi torch with an
axially symmetric burner tip and a propane supply tube with an
orifice diameter of 0.006 inches (0.15 mm). The length of the burner
tube must be 2\7/8\ inches (71 mm). The propane flow must be
adjusted via gas pressure through an in-line regulator to produce a
blue inner cone length of \3/4\ inch (19 mm). A \3/4\ inch (19 mm)
guide (such as a thin strip of metal) may be soldered to the top of
the burner to aid in setting the flame height. The overall flame
length must be approximately 5 inches long (127 mm). Provide a way
to move the burner out of the ignition position so that the flame is
horizontal and at least 2 inches (50 mm) above the specimen plane.
See figure F6.
[GRAPHIC] [TIFF OMITTED] TP17AU09.009
(5) Thermocouples. Install a 24 American Wire Gauge (AWG) Type K
(Chromel- Alumel) thermocouple in the test chamber for temperature
monitoring. Insert it into the chamber through a small hole drilled
through the back of the chamber. Place the thermocouple so that it
extends 11 inches (279 mm) out from the back of the chamber wall,
11\1/2\ inches (292 mm) from the right side of the chamber wall, and
is 2 inches (51 mm) below the radiant panel. The use of other
thermocouples is optional.
(6) Calorimeter. The calorimeter must be a one-inch cylindrical
water-cooled, total heat flux density, foil type Gardon Gage that
has a range of 0 to 5 BTU/ft\2\ -second (0 to 5.7 Watts/cm\2\).
(7) Calorimeter calibration specification and procedure.
(i) Calorimeter specification.
(A) Foil diameter must be 0.25 0.005 inches (6.35
0.13 mm).
(B) Foil thickness must be 0.0005 0.0001 inches
(0.013 0.0025 mm).
(C) Foil material must be thermocouple grade Constantan.
(D) Temperature measurement must be a Copper Constantan
thermocouple.
(E) The copper center wire diameter must be 0.0005 inches (0.013
mm).
(F) The entire face of the calorimeter must be lightly coated
with ``Black Velvet'' paint having an emissivity of 96 or greater.
(ii) Calorimeter calibration.
(A) The calibration method must be by comparison to a like
standardized transducer.
(B) The standardized transducer must meet the specifications
given in paragraph VI(b)(6) of this appendix.
(C) Calibrate the standard transducer against a primary standard
traceable to the National Institute of Standards and Technology
(NIST).
(D) The method of transfer must be a heated graphite plate.
(E) The graphite plate must be electrically heated, have a clear
surface area on each side of the plate of at least 2 by 2 inches (51
by 51 mm), and be \1/8\ inch \1/16\ inch thick (3.2
1.6 mm).
(F) Center the 2 transducers on opposite sides of the plates at
equal distances from the plate.
(G) The distance of the calorimeter to the plate must be no less
than 0.0625 inches (1.6 mm), nor greater than 0.375 inches (9.5 mm).
(H) The range used in calibration must be at least 0-3.5 BTUs/
ft\2\ second (0-3.9 Watts/cm\2\) and no greater than 0-5.7 BTUs/
ft\2\ second (0-6.4 Watts/cm\2\).
(I) The recording device used must record the 2 transducers
simultaneously or at least within \1/10\ of each other.
(8) Calorimeter fixture. With the sliding platform pulled out of
the chamber, install the calorimeter holding frame and place a sheet
of non-combustible material in the bottom of the sliding platform
adjacent to the holding frame. This will prevent heat losses during
calibration. The frame must be 13\1/8\ inches (333 mm) deep (front
to back) by 8 inches (203 mm) wide and must rest on the top of the
sliding platform. It must be fabricated of \1/8\ inch (3.2 mm) flat
stock steel and have an opening that accommodates a \1/2\ inch (12.7
mm) thick piece of refractory board, which is level with the top of
the sliding platform. The board must have three 1-inch (25.4 mm)
diameter holes drilled through the board for calorimeter insertion.
The distance to the radiant panel surface from the centerline of the
first hole (``zero'' position) must be 7\1/2\ \1/8\
inches (191 3 mm). The distance between the centerline
of the first hole to the centerline of the second hole must be 2
inches (51 mm). It must also be the same distance from the
centerline of the second hole to the centerline of the third hole.
See figure F7. A calorimeter holding frame that differs in
construction is acceptable as long as the height from the centerline
of the first hole to the radiant panel and the distance between
holes is the same as described in this paragraph.
[[Page 41554]]
[GRAPHIC] [TIFF OMITTED] TP17AU09.010
(9) Instrumentation. Provide a calibrated recording device with
an appropriate range or a computerized data acquisition system to
measure and record the outputs of the calorimeter and the
thermocouple. The data acquisition system must be capable of
recording the calorimeter output every second during calibration.
(10) Timing device. Provide a stopwatch or other device,
accurate to 1 second/hour, to measure the time of
application of the pilot burner flame.
(c) Test specimens.
(1) Specimen preparation. Prepare and test a minimum of three
test specimens. If an oriented film cover material is used, prepare
and test both the warp and fill directions.
(2) Construction. Test specimens must include all materials used
in construction of the insulation (including batting, film, scrim,
tape, etc.). Cut a piece of core material such as foam or
fiberglass, and cut a piece of film cover material (if used) large
enough to cover the core material. Heat sealing is the preferred
method of preparing fiberglass samples, since they can be made
without compressing the fiberglass (``box sample''). Cover materials
that are not heat sealable may be stapled, sewn, or taped as long as
the cover material is over-cut enough to be drawn down the sides
without compressing the core material. The fastening means should be
as continuous as possible along the length of the seams. The
specimen thickness must be of the same thickness as installed in the
airplane.
(3) Specimen Dimensions. To facilitate proper placement of
specimens in the sliding platform housing, cut non-rigid core
materials, such as fiberglass, 12\1/2\ inches (318 mm) wide by 23
inches (584 mm) long. Cut rigid materials, such as foam, 11\1/2\
\1/4\ inches (292 mm 6 mm) wide by 23
inches (584 mm) long in order to fit properly in the sliding
platform housing and provide a flat, exposed surface equal to the
opening in the housing.
(d) Specimen conditioning. Condition the test specimens at 70
5 [deg]F (21 2 [deg]C) and 55 percent
10 percent relative humidity, for a minimum of 24 hours
prior to testing.
(e) Apparatus Calibration.
(1) With the sliding platform out of the chamber, install the
calorimeter holding frame. Push the platform back into the chamber
and insert the calorimeter into the first hole (``zero'' position).
See figure F7. Close the bottom door located below the sliding
platform. The distance from the centerline of the calorimeter to the
radiant panel surface at this point must be 7\1/2\ inches \1/8\ (191 mm 3). Before igniting the radiant
panel, ensure that the calorimeter face is clean and that there is
water running through the calorimeter.
(2) Ignite the panel. Adjust the fuel/air mixture to achieve 1.5
BTUs/feet\2\ -second 5 percent (1.7 Watts/cm\2\ 5 percent) at the ``zero'' position. If using an electric
panel, set the power controller to achieve the proper heat flux.
Allow the unit to reach steady state (this may take up to 1 hour).
The pilot burner must be off and in the down position during this
time.
(3) After steady-state conditions have been reached, move the
calorimeter 2 inches (51 mm) from the ``zero'' position (first hole)
to position 1 and record the heat flux. Move the calorimeter to
position 2 and record the heat flux. Allow enough time at each
position for the calorimeter to stabilize. Table 1 depicts typical
calibration values at the three positions.
Table 1--Calibration Table
------------------------------------------------------------------------
Position BTU's/feet\2\ sec Watts/cm\2\
------------------------------------------------------------------------
``Zero'' Position............... 1.5 1.7
Position 1...................... 1.51-1.50-1.49 1.71-1.70-1.69
Position 2...................... 1.43-1.44 1.62-1.63
------------------------------------------------------------------------
(4) Open the bottom door, remove the calorimeter and holder
fixture. Use caution as the fixture is very hot.
(f) Test Procedure.
(1) Ignite the pilot burner. Ensure that it is at least 2 inches
(51 mm) above the top of the platform. The burner must not contact
the specimen until the test begins.
(2) Place the test specimen in the sliding platform holder.
Ensure that the test sample surface is level with the top of the
platform. At ``zero'' point, the specimen surface must be 7\1/2\
inches \1/8\ inch (191 mm 3) below the
radiant panel.
(3) Place the retaining/securing frame over the test specimen.
It may be necessary (due to compression) to adjust the sample (up or
down) in order to maintain the distance from the sample to the
radiant panel (7\1/2\ inches \1/8\ inch (191 mm 3) at ``zero'' position). With film/fiberglass assemblies, it
is critical to make a slit in the film cover to purge any air
inside. This allows the operator to maintain the proper test
specimen position (level with the top of the platform) and to allow
ventilation of gases during testing. A longitudinal slit,
approximately 2 inches (51 mm) in length, must be centered 3 inches
\1/2\ inch (76 mm 13 mm) from the left
flange of the securing frame. A utility knife is acceptable for
slitting the film cover.
(4) Immediately push the sliding platform into the chamber and
close the bottom door.
[[Page 41555]]
(5) Bring the pilot burner flame into contact with the center of
the specimen at the ``zero'' point and simultaneously start the
timer. The pilot burner must be at a 27 degree angle with the sample
and be approximately \1/2\ inch (12 mm) above the sample. See figure
F7. A stop, as shown in figure F8, allows the operator to position
the burner correctly each time.
[GRAPHIC] [TIFF OMITTED] TP17AU09.011
(6) Leave the burner in position for 15 seconds and then remove
to a position at least 2 inches (51 mm) above the specimen.
(g) Report.
(1) Identify and describe the test specimen.
(2) Report any shrinkage or melting of the test specimen.
(3) Report the flame propagation distance. If this distance is
less than 2 inches, report this as a pass (no measurement required).
(4) Report the after-flame time.
(h) Requirements.
(1) There must be no flame propagation beyond 2 inches (51 mm)
to the left of the centerline of the pilot flame application.
(2) The flame time after removal of the pilot burner may not
exceed 3 seconds on any specimen.
71. Add a new Appendix K to part 23 to read as follows:
Appendix K to Part 23--Relationship Among Airplane Classes,
Probabilities, Severity of Failure Conditions, and Software and Complex
Hardware Development Assurance Levels
--------------------------------------------------------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------------------------------------------------------
Classification of failure No safety effect Minor Major Hazardous Catastrophic
conditions
--------------------------------------------------------------------------------------------------------------------------------------------------------
Allowable qualitative probability No probability Probable Remote Extremely remote Extremely improbable
requirement
--------------------------------------------------------------------------------------------------------------------------------------------------------
Effect on Airplane................. No effect on Slight reduction in Significant reduction Large reduction in Normally with hull
operational functional in functional functional loss.
capabilities or capabilities or capabilities or capabilities or
safety. safety margins. safety margins. safety margins.
Effect on Occupants................ Inconvenience for Physical discomfort Physical distress to Serious or fatal Multiple fatalities
passengers. for passengers. passengers, possibly injury to an
including injuries. occupant.
Effect on Flight Crew.............. No effect on flight Slight increase in Physical discomfort Physical distress or Fatal Injury or
crew. workload or use of or a significant excessive workload incapacitation.
emergency procedures. increase in workload. impairs ability to
perform tasks.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Classes of Airplanes Allowable Quantitative Probabilities and Software (SW) and Complex Hardware (HW) Development Assurance Levels (Note
2)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Class I
(Typically SRE under 6,000). HW Development P=C, S=D. S=D. S=C.
Assurance Levels
Requirement.
Class II
(Typically MRE, STE, or MTE under No Probability or SW & <10-3, Note 1, P=D.... <10-5, Notes 1 & 4, <10-6, Notes 4, P=C, <10-7, Note 3, P=C,
6,000). HW Development P=C, S=D. S=C. S=C.
Assurance Levels
Requirement.
[[Page 41556]]
Class III
(Typically SRE, STE, MRE, & MTE No Probability or SW & <10-3, Note 1, P=D.... <10-5, Notes 1 & 4, <10-7, Notes 4, P=C, <10-8, Note 3, P=B,
equal or over 6,000). HW Development P=C, S=D. S=C. S=C.
Assurance Levels
Requirement.
Class IV
(Typically Commuter Category)...... No Probability or SW & <10-3, Note 1, P=D.... <10-5, Notes 1 & 4, <10-7, Notes 4, P=B, <10-9, Note 3, P=A,
HW Development P=C, S=D. S=C. S=B.
Assurance Levels
Requirement.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note 1: Numerical values indicate an order of probability range and are provided here as a reference.
Note 2: The alphabets denote the typical SW and HW Development Assurance Levels for Primary System (P) and Secondary System (S). For example, HW or SW
Development Assurance Level A on Primary System is noted by P=A.
Note 3: At airplane function level, no single failure will result in a Catastrophic Failure Condition.
Note 4: Secondary System (S) may not be required to meet probability goals. If installed, S must meet stated criteria.
Acronyms: SRE--single, reciprocating engine, MRE--multiple, reciprocating engines, STE--single, turbine engine, MTE--multiple, turbine engines, SW--
software, HW--hardware.
Issued in Washington, DC, on August 6, 2009.
Dorenda D. Baker,
Director, Aircraft Certification Service, Office of Aviation Safety.
[FR Doc. E9-19350 Filed 8-14-09; 8:45 am]
BILLING CODE 4910-13-P