[Federal Register Volume 74, Number 170 (Thursday, September 3, 2009)]
[Rules and Regulations]
[Pages 45546-45550]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E9-21299]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM409; Special Conditions No. 25-386-SC]


Special Conditions: Boeing Model 737-600/-700/-700C/-800/-900 and 
900ER Series Airplanes; Seats With Inflatable Lapbelts

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions; request for comments.

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SUMMARY: These special conditions are issued for Boeing Model 737-600/-
700/-700C/-800/-900 and 900ER series airplanes. These airplanes, 
manufactured by Boeing Commercial Airplanes, will have novel or unusual 
design features associated with seats with inflatable lapbelts. Special 
Conditions No. 25-187-SC were issued on October 3, 2001, addressing 
this issue for the Boeing Model 777 series airplanes. The applicable 
airworthiness regulations do not contain adequate or appropriate safety 
standards for this design feature. These special conditions contain the 
additional safety standards that the Administrator considers necessary 
to establish a level of safety equivalent to that established by the 
existing airworthiness standards.

DATES: The effective date of these special condition is August 7, 2009. 
We must receive your comments by: October 19, 2009.

ADDRESSES: You must mail two copies of your comments to: Federal 
Aviation Administration, Transport Airplane Directorate, Attn: Rules 
Docket (ANM-113), Docket No. NM409, 1601 Lind Avenue, SW., Renton, 
Washington, 98057-3356. You may deliver two copies to the Transport 
Airplane Directorate at the above address. You must mark your comments: 
Docket No. NM409. You can inspect comments in the Rules Docket 
weekdays, except Federal holidays, between 7:30 a.m. and 4 p.m.

FOR FURTHER INFORMATION CONTACT: John Shelden, FAA, Airframe and Cabin 
Safety Branch, ANM-115, Transport Airplane Directorate, Aircraft 
Certification Service, 1601 Lind Avenue, SW., Renton, Washington 98057-
3356; telephone (425) 227-2785 facsimile (425) 227-1232.

SUPPLEMENTARY INFORMATION: The FAA has determined that notice of, and 
opportunity for public comment on, these special conditions are 
impracticable because these procedures would significantly delay 
issuance of the design approval and thus delivery of the affected 
airplanes. In addition, the substance of these special conditions has 
been subject to the public-comment process in several prior instances 
with no substantive comments received. The FAA therefore finds that 
good cause exists for making these special conditions effective upon 
issuance.

Comments Invited

    We invite interested people to take part in this rulemaking by 
sending written comments, data, or views. The most helpful comments 
reference a specific portion of the special conditions, explain the 
reason for any recommended change, and include supporting data. We ask 
that you send us two copies of written comments.
    We will file in the docket all comments we receive, as well as a 
report summarizing each substantive public contact with FAA personnel 
concerning these special conditions. You can inspect the docket before 
and after the comment closing date. If you wish to review the docket in 
person, go to the address in the ADDRESSES section of this preamble 
between 7:30 a.m. and 4 p.m., Monday through Friday, except Federal 
holidays.
    We will consider all comments we receive by the closing date for 
comments. We will consider comments filed late if it is possible to do 
so without incurring expense or delay. We may change these special 
conditions in light of the comments we receive.
    If you want the FAA to acknowledge receipt of your comments on 
these special conditions, include with your comments a self-addressed, 
stamped postcard on which you have written the docket number. We will 
stamp the date on the postcard and mail it back to you.

Background

    On July 8, 2008, Boeing Commercial Airplanes applied for an 
amendment to type certificate No. A16WE to include the new Boeing Model 
737-600/-700/-700C-800/-900 and 900ER series airplanes. These special 
conditions allow installation of inflatable lap belts for head injury 
protection on certain seats in Boeing Model 737-600/-700/-700C/800/-900 
and 900ER series airplanes. The FAA has issued similar special 
conditions, No. 25-187-SC and subsequently 25-187A-SC for Boeing Model 
777 series airplanes and Special Condition No. 25-148-SC for Boeing 
Model 767 series airplanes.
    The inflatable lapbelt is designed to limit occupant forward 
excursion if an accident occurs. This will reduce the potential for 
head injury, thereby reducing the Head Injury Criterion (HIC) 
measurement, required by Title 14, Code of Federal Regulations (14 
CFR), 25.562(c)(5). The inflatable lapbelt behaves similarly to an 
automotive inflatable airbag, but in this case the airbag is integrated 
into the lapbelt, and inflates away from the seated occupant. While 
inflatable airbags are now standard in the automotive industry, the use 
of an inflatable lapbelt is novel for commercial aviation.
    Title 14, Code of Federal Regulations (14 CFR) 121.311(j) requires 
that no person may operate a transport category airplane type 
certificated after January 1, 1958, and manufactured on or after 
October 27, 2009, in passenger-carrying operations, after October 27, 
2009, unless all passenger and flight attendant seats on an airplane 
operated under part 121 meet the requirements of Sec.  25.562 in effect 
on or after June 16, 1988.
    The Boeing Model 737-600/-700/-700C/-800/-900 and 900ER series 
airplanes, manufactured before October 27, 2009, operated under part 
121, are required to show compliance with certain aspects of Sec.  
25.562 as specified per Type Certificate No. A16WE. Boeing Model 737-
600/-700/-700C/-800/-900 and 900ER series airplanes manufactured on or 
after October 27, 2009, operated under part 121, must meet all of the 
requirements of Sec.  25.562 for passenger and flight attendant seats. 
It is in the interest of installers to show full compliance with Sec.  
25.562, so that an operator under part 121 may be able to use the 
airplane without having to do additional certification work. In 
addition, some foreign civil airworthiness authorities have invoked 
these same operator requirements in the form of airworthiness 
directives.
    Occupants must be protected from head injury, as required by Sec.  
25.785, by either the elimination of any injurious object within the 
striking radius of the head, or by padding. Traditionally, this has 
required a setback of 35 inches from any bulkhead or other rigid 
interior feature or, where not practical, specified types of padding. 
The relative effectiveness of these means of injury protection was not 
quantified. With the adoption of Amendment 25-64 to part 25, 
specifically Sec.  25.562, a new standard that quantifies required head 
injury protection was created.

[[Page 45547]]

    Each seat type design approved for crew or passenger occupancy 
during takeoff and landing, as required by Sec.  25.562, must 
successfully complete dynamic tests or be demonstrated by rational 
analysis based on dynamic tests of a similar type seat. In particular, 
the regulations require that persons not suffer serious head injury 
under the conditions specified in the tests, and that protection must 
be provided or the seat be designed so that the head impact does not 
exceed a HIC value of 1000 units. While the test conditions described 
for HIC are detailed and specific, it is the intent of the requirement 
that an adequate level of head injury protection be provided for 
passengers in a severe crash.
    Because Sec. Sec.  25.562 and 25.785 and associated guidance do not 
adequately address seats with inflatable lapbelts, the FAA recognizes 
that appropriate pass/fail criteria need to be developed that fully 
address the safety concerns specific to occupants of these seats.

Type Certification Basis

    Under the provisions of 14 CFR 21.101, Boeing must show that the 
Boeing Model 737-600/-700/-700C/ -800/-900 and 900ER series airplanes 
meet the applicable provisions of the regulations incorporated by 
reference in Type Certificate No. A16WE, or the applicable regulations 
in effect on the date of application for the change. The regulations 
incorporated by reference in the type certificate are commonly referred 
to as the ``original type certification basis.'' The regulations 
incorporated by reference in Type Certificate No. A16WE are as follows: 
Part 25, as amended by Amendment 25-1 through Amendment 25-77, for 
Boeing Model 737-600, -700, and -800 series airplanes, with the 
exceptions listed on the type certificate; Title 14 CFR part 25, as 
amended by Amendment 25-1 through Amendment 25-91, for Boeing Model 
737-700C and -900 series airplanes, with the exceptions listed on the 
type certificate; and part 25, as amended by Amendment 25-1 through 
Amendment 25-108, for the Boeing model 737-900ER series airplanes, with 
the exceptions listed on the type certificate.
    In addition, the certification basis includes certain special 
conditions, exemptions, or later amended sections of the applicable 
parts that are not relevant to these special conditions.
    If the regulations incorporating reference do not contain adequate 
or appropriate safety standards for the Boeing Model 737-600/-700/-
700C/ -800/-900 and 900ER series airplanes because of a novel or 
unusual design feature, special conditions are prescribed under Sec.  
21.16.
    In addition to the applicable airworthiness regulations and special 
conditions, the Boeing Model 737-600/-700/-700C/-800/-900 and 900ER 
series airplanes must comply with the fuel vent and exhaust emission 
requirements of 14 CFR part 34 and the noise certification requirements 
of 14 CFR part 36.
    The FAA issues special conditions as defined in 14 CFR 11.19, in 
accordance with Sec.  11.38, and they become part of the type 
certification basis under Sec.  21.17(a)(2).
    Special conditions are initially applicable to the model for which 
they are issued. Should the type certificate for that model be amended 
later to include any other model that incorporates the same or similar 
novel or unusual design feature, or should any other model already 
included on the same type certificate be modified to incorporate the 
same or similar novel or unusual design feature, the special conditions 
would also apply to the other model under Sec.  21.101.

Novel or Unusual Design Features

    Boeing Model 737-600/-700/-700C/ -800/-900 and 900ER series 
airplanes will incorporate the following novel or unusual design 
features: seats with inflatable lapbelts.

Discussion

    The inflatable lapbelt has two potential advantages over other 
means of head impact protection. First, it can provide significantly 
greater protection than would be expected with energy-absorbing pads, 
and second, it can provide essentially equivalent protection for 
occupants of all stature. These are significant advantages from a 
safety standpoint, since such devices will likely provide a level of 
safety that exceeds the minimum standards of part 25. Conversely, 
inflatable lapbelts in general are active systems and must be relied 
upon to activate properly when needed, as opposed to an energy-
absorbing pad or upper torso restraint that is passive, and always 
available. Therefore, the potential advantages must be balanced against 
this and other potential disadvantages to develop standards for this 
design feature.
    The FAA has considered the installation of inflatable lapbelts to 
have two primary safety concerns: First, that they perform properly 
under foreseeable operating conditions, and second, that they do not 
perform in a manner or at such times as would constitute a hazard to 
the airplane or occupants. This latter point has the potential to be 
the more rigorous of the requirements, owing to the active nature of 
the system.
    The inflatable lapbelt will rely on electronic sensors for 
signaling and pyrotechnic charges for activation so that it is 
available when needed. These same devices could be susceptible to 
inadvertent activation, causing deployment in a potentially unsafe 
manner. The consequences of such deployment must be considered in 
establishing the reliability of the system. Boeing must substantiate 
that the effects of an inadvertent deployment in flight are either not 
a hazard to the airplane, or that such deployment is an extremely 
improbable occurrence (less than 10-9 per flight hour). The 
effect of an inadvertent deployment on a passenger or crewmember that 
might be positioned close to the inflatable lapbelt should also be 
considered. The person could be either standing or sitting. A minimum 
reliability level will have to be established for this case, depending 
upon the consequences, even if the effect on the airplane is 
negligible.
    The potential for an inadvertent deployment could be increased as a 
result of conditions in service. The installation must take into 
account wear and tear so that the likelihood of an inadvertent 
deployment is not increased to an unacceptable level. In this context, 
an appropriate inspection interval and self-test capability are 
considered necessary. Other outside influences are lightning and high 
intensity electromagnetic fields (HIRF). Existing regulations regarding 
lightning Sec.  25.1316, HIRF Sec.  25.1317, and HIRF special condition 
for the Boeing Model 737-600/-700/-700C/-800/-900 and 900ER series 
airplanes, SC-25-ANM-132, are applicable. For compliance with those 
conditions, if inadvertent deployment could cause a hazard to the 
airplane, the inflatable lapbelt is considered a critical system; if 
inadvertent deployment could cause injuries to persons, the inflatable 
lapbelt should be considered an essential system. Finally, the 
inflatable lapbelt installation should be protected from the effects of 
fire, so that an additional hazard is not created by, for example, a 
rupture of the pyrotechnic squib.
    For an effective safety system, the inflatable lapbelt must 
function properly and must not introduce any additional hazards to 
occupants as a result of its functioning. There are several areas where 
the inflatable lapbelt differs from traditional occupant protection 
systems, and requires special conditions to ensure adequate 
performance.
    Because the inflatable lapbelt is essentially a single use device, 
there is

[[Page 45548]]

the potential that it could deploy under crash conditions that are not 
sufficiently severe as to require head injury protection from the 
inflatable lapbelt. Since an actual crash is frequently composed of a 
series of impacts before the airplane comes to rest, this could render 
the inflatable lapbelt useless if a larger impact follows the initial 
impact. This situation does not exist with energy absorbing pads or 
upper torso restraints, which tend to provide continuous protection 
regardless of severity or number of impacts in a crash event. 
Therefore, the inflatable lapbelt installation should be such that the 
inflatable lapbelt will provide protection when it is required, by not 
expending its protection during a less severe impact. Also, it is 
possible to have several large impact events during the course of a 
crash, but there will be no requirement for the inflatable lapbelt to 
provide protection for multiple impacts.
    Since each occupant's restraint system provides protection for that 
occupant only, the installation must address seats that are unoccupied. 
It will be necessary to show that the required protection is provided 
for each occupant regardless of the number of occupied seats and that 
unoccupied seats may have lapbelts that are active.
    The inflatable lap belt should be effective for a wide range of 
occupants. The FAA has historically considered the range from the fifth 
percentile female to the ninety-fifth percentile male as the range of 
occupants that must be taken into account. In this case, the FAA is 
proposing consideration of a broader range of occupants, due to the 
nature of the lapbelt installation and its close proximity to the 
occupant. In a similar vein, these persons could have assumed the brace 
position, for those accidents where an impact is anticipated. Test data 
indicate that occupants in the brace position do not require 
supplemental protection, so it would not be necessary to show that the 
inflatable lapbelt will enhance the brace position. However, the 
inflatable lapbelt must not introduce a hazard when it is deployed into 
a seated, braced occupant.
    Another area of concern is the use of seats, so equipped, by 
children whether they are lap-held, sitting in approved child safety 
seats, or occupying the seat directly. Although specifically prohibited 
by the FAA operating regulations, the use of the supplementary loop 
belt (``belly belt'') may be required by other civil aviation 
authorities, and should also be considered with the end goal of meeting 
those regulations. Similarly, if the seat is occupied by a pregnant 
woman, the installation needs to address such usage, either by 
demonstrating that it will function properly, or by adding appropriate 
limitation on usage.
    Since the inflatable lapbelt will be electrically powered, there is 
the possibility that the system could fail due to a separation in the 
fuselage. Since this system is intended as crash/post-crash protection 
means, failure due to fuselage separation is not acceptable. As with 
emergency lighting, the system should function properly if such a 
separation occurs at any point in the fuselage.
    Since the inflatable lapbelt is likely to have a large volume 
displacement, the inflated bag could potentially impede egress of 
passengers. Since the bag deflates to absorb energy, it is likely that 
an inflatable lapbelt would be deflated when persons try to leave their 
seats. Nonetheless, it is appropriate to specify a time interval after 
which the inflatable lapbelt may not impede rapid egress. The maximum 
time allowed for an exit to open fully after actuation is ten seconds, 
according to Sec.  25.809(b)(2). Therefore it was chosen as the time 
interval that the inflatable lapbelt must not impede rapid egress from 
the seat after it is deployed. In actuality, it is unlikely that an 
exit would be prepared by a flight attendant this quickly in an 
accident severe enough to warrant deployment of the inflatable lapbelt. 
The inflatable lapbelt will likely deflate much quicker then ten 
seconds.
    This potential impediment to rapid egress is even more critical at 
the seats installed in the emergency exit rows. Installation of the 
inflatable restraints at the Type III exit rows presents different 
egress concerns as compared with front row seats. However, the need to 
address egress is already part of the special conditions so there is no 
change to the special conditions at this time. As noted below, the 
method of compliance with the special condition may involve specific 
considerations when the inflatable restraint is installed at Type III 
exits. From Sec.  25.813 there are clear requirements that there must 
be access to the exit from the main aisle in the form of an 
unobstructed passageway, and no interference in opening the exit. The 
restraint system must not create an impediment to the access to, and 
the opening, of the exit. These lap belts should be evaluated in the 
exit row under existing regulations (Sec. Sec.  25.809 and 25.813) and 
guidance material. The inflatable lap belts must also be evaluated in 
post crash conditions, and should be evaluated using representative 
restraint systems in the bag deployed condition.
    This evaluation would include reviewing the access to and opening 
of the exit, specifically for obstructions in the egress path, and any 
interferences in opening the exit. Each unique interior configuration 
must be considered, e.g., passageway width, single or dual passageways 
with outboard seat removed, etc. If the restraint creates any 
obstruction or interference, it is likely that it could impede the 
rapid egress of the airplane. In some cases, the passenger is the one 
who will open the exit, such as a Type III over wing hatch. Project 
specific means-of-compliance guidance is likely necessary if these 
restraint systems are installed at the Type III exit rows.
    Finally, it should be noted that the special conditions are 
applicable to the inflatable lapbelt system as installed. The special 
conditions are not an installation approval. Therefore, while the 
special conditions relate to each such system installed, the overall 
installation approval is separate, and must consider the combined 
effects of all such systems installed.
    Boeing is proposing to install the following novel or unusual 
design feature of inflatable lap belts on certain seats of Boeing Model 
737-600/-700/ -700C/-800/-900 and 900ER series airplanes, to reduce the 
potential for head injury if an accident occurs. The inflatable lapbelt 
works similar to an automotive inflatable airbag, except that the 
airbag is integrated with the lap belt of the restraint system.
    The performance criteria for head injury protection in objective 
terms is stated in Sec.  25.562. However, none of these criteria are 
adequate to address the specific issues raised concerning seats with 
inflatable lapbelts. The FAA has therefore determined that, in addition 
to the requirements of part 25, special conditions are needed to 
address requirements particular to the installation of seats with 
inflatable lapbelts.
    Accordingly, in addition to the passenger injury criteria specified 
in Sec.  25.785, these special conditions are proposed for the Boeing 
Model 737 series airplanes equipped with inflatable lapbelts. Other 
conditions may be developed, as needed, based on further FAA review and 
discussions with the manufacturer and civil aviation authorities.
    For a passenger safety system, the inflatable lapbelt is unique in 
that it is both an active and entirely autonomous device. While the 
automotive industry has good experience with inflatable airbags, the 
conditions of use and reliance on the inflatable lapbelt as the sole 
means of injury protection are quite

[[Page 45549]]

different. In automobile installations, the airbag is a supplemental 
system and works in conjunction with an upper torso restraint. In 
addition, the crash event is more definable and of typically shorter 
duration, which can simplify the activation logic. The airplane-
operating environment is also quite different from automobiles and 
includes the potential for greater wear and tear, and unanticipated 
abuse conditions (due to galley loading, passenger baggage, etc.). 
Airplanes also operate where exposure to high intensity electromagnetic 
fields could affect the lapbelt activation system.
    The current Special Conditions for the Boeing Model 777 series 
airplanes, Special Conditions No. 25-187A-SC, was amended to address 
flammability of the airbag material. The manufacturer of the inflatable 
lapbelt was unable to develop a fabric that would meet the inflation 
requirements for the bag and the flammability requirements of Part 
I(a)(1)(ii) of appendix F to part 25. The fabrics that were developed 
that met the flammability requirement did not produce acceptable 
deployment characteristics. However, the manufacturer was able to 
develop a fabric that meets the less stringent flammability 
requirements of Part I(a)(1)(iv) of appendix F to part 25 which has 
acceptable deployment characteristics.
    Part I of appendix F to part 25 specifies the flammability 
requirements for interior materials and components. There is no 
reference to inflatable restraint systems in appendix F, because such 
devices did not exist at the time the flammability requirements were 
written. The existing requirements are based on both material types, as 
well as use, and have been specified in light of the state-of-the-art 
of materials available to perform a given function. Without a specific 
reference, the default requirement would be for the type of material 
used to make the inflatable restraint, which is a fabric in this case. 
However, in writing a special condition, the FAA must also consider the 
use of the material, and whether the default requirement is 
appropriate. In this case, the specialized function of the inflatable 
restraint means that highly specialized materials are needed. The 
standard normally applied to fabrics is a 12-second vertical ignition 
test. However, materials that meet this standard do not perform 
adequately as inflatable restraints. Since the safety benefit of the 
inflatable restraint is very significant, the flammability standard 
appropriate for these devices should not screen out suitable materials 
and thereby effectively eliminate the use of inflatable restraints. The 
FAA will need to establish a balance between the safety benefit of the 
inflatable restraint and its flammability performance. Right now, the 
2.5-inch per minute horizontal test is considered to provide that 
balance. As the state-of-the-art in materials progresses (which is 
expected), the FAA may change this standard in subsequent special 
conditions to account for improved materials.
    The following special conditions can be characterized as addressing 
either the safety performance of the system, or the system's integrity 
against inadvertent activation. Because a crash requiring use of the 
inflatable lapbelts is a rare event, and because the consequences of an 
inadvertent activation are potentially quite severe, these latter 
requirements are probably more rigorous from a design standpoint.

Applicability

    These special conditions are applicable to the Boeing Model 737-
600/-700/-700C/-800/-900 and 900ER series airplanes. Should Boeing 
apply at a later date for a change to the type certificates to include 
another model that incorporates the same novel or unusual design 
feature, or should any other model already included on the same type 
certificate be modified to incorporate the same or similar novel or 
unusual design feature, the special conditions would also apply to the 
other model as well.

Conclusion

    This action affects only certain novel or unusual design features 
on the Boeing Model 737-600/-700/-700C/ -800/-900 and 900ER series 
airplanes. It is not a rule of general applicability, and it affects 
only Boeing Model 737-600/ -700/-700C/-800/-900 and 900ER series 
airplanes listed on Type Certificate No. A16WE.

List of Subjects in 14 CFR Part 25

    Aircraft, Aviation safety, reporting and recordkeeping 
requirements.

0
The authority citation for these special conditions is as follows:

    Authority:  49 U.S.C. 106(g), 40113, 44701, 44702, 44704.

The Special Conditions

    Accordingly, pursuant to the authority delegated to me by the 
administrator, the following special conditions are issued as part of 
the type certification basis for the Boeing Model 737-600/-700/-700C/-
800/ and 900ER series airplanes with inflatable lapbelts installed.

1. Seats With Inflatable Lapbelts

    It must be shown that the inflatable lapbelt will deploy and 
provide protection under crash conditions where it is necessary to 
prevent serious head injury. The means of protection must take into 
consideration a range of stature from a two-year-old child to a ninety-
fifth percentile male. The inflatable lapbelt must provide a consistent 
approach to energy absorption throughout that range of occupants. In 
addition, the following situations must be considered:
    a. The seat occupant is holding an infant.
    b. The seat occupant is a child in a child restraint device.
    c. The seat occupant is a child not using a child restraint device.
    d. The seat occupant is a pregnant woman.
    2. The inflatable lapbelt must provide adequate protection for each 
occupant regardless of the number of occupants of the seat assembly, 
considering that unoccupied seats may have active seatbelts.
    3. The design must prevent the inflatable lapbelt from being either 
incorrectly buckled or incorrectly installed such that the inflatable 
lapbelt would not properly deploy. Alternatively, it must be shown that 
such deployment is not hazardous to the occupant, and will provide the 
required head injury protection.
    4. It must be shown that the inflatable lapbelt system is not 
susceptible to inadvertent deployment as a result of wear and tear, or 
inertial loads resulting from in-flight or ground maneuvers (including 
gusts and hard landings), likely to be experienced in service.
    5. Deployment of the inflatable lapbelt must not introduce injury 
mechanisms the seated occupant, or result in injuries that could impede 
rapid egress. This assessment should include an occupant who is in the 
brace position when it deploys and an occupant whose belt is loosely 
fastened.
    6. It must be shown that an inadvertent deployment, that could 
cause injury to a standing or sitting person, is improbable.
    7. It must be shown that inadvertent deployment of the inflatable 
lapbelt, during the most critical part of the flight, will either not 
cause a hazard to the airplane or is extremely improbable.
    8. It must be shown that the inflatable lapbelt will not impede 
rapid egress of occupants 10 seconds after its deployment.
    9. The system must be protected from lightning and HIRF. The 
threats specified in existing regulations

[[Page 45550]]

regarding lightning, Sec.  25.1316, HIRF, Sec.  25.1317, and existing 
HIRF special conditions for the Boeing Model 737-600/-700/-700C/-800/-
900 and 900ER series airplanes, SC-25-ANM-132, are incorporated by 
reference for the purpose of measuring lightning and HIRF protection. 
For the purposes of complying with HIRF requirements, the inflatable 
lapbelt system is considered a ``critical system'' if its deployment 
could have a hazardous effect on the airplane; otherwise it is 
considered an ``essential'' system.
    10. The inflatable lapbelt must function properly after loss of 
normal aircraft electrical power, and after a transverse separation of 
the fuselage at the most critical location. A separation at the 
location of the lapbelt does not have to be considered.
    11. It must be shown that the inflatable lapbelt will not release 
hazardous quantities of gas or particulate matter into the cabin.
    12. The inflatable lapbelt installation must be protected from the 
effects of fire such that no hazard to occupants will result.
    13. There must be a means for a crewmember to verify the integrity 
of the inflatable lapbelt activation system prior to each flight or it 
must be demonstrated to reliably operate between inspection intervals.
    14. The inflatable material may not have an average burn rate of 
greater than 2.5 inches/minute when tested using the horizontal 
flammability test as defined in 14 CFR part 25, appendix F, part I, 
paragraph (b)(5).

    Issued in Renton, Washington, on August 7, 2009.
Stephen P. Boyd,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E9-21299 Filed 9-2-09; 8:45 am]
BILLING CODE 4910-13-P