Special Conditions: Airbus A318, A319, A320 and A321 Series Airplanes; Inflatable Restraints, 70257-70261 [E8-27541]

Agencies

• Federal Aviation Administration
• DEPARTMENT OF TRANSPORTATION

[Federal Register Volume 73, Number 225 (Thursday, November 20, 2008)]
[Rules and Regulations]
[Pages 70257-70261]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E8-27541]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM394; Special Conditions No. 25-375-SC]


Special Conditions: Airbus A318, A319, A320 and A321 Series 
Airplanes; Inflatable Restraints

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions; request for comments.

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SUMMARY: These special conditions are issued for the Airbus A318, A319, 
A320, and A321 series airplanes. These airplanes will have a novel or 
unusual design feature associated with a passenger restraint system 
that contains an integrated inflatable airbag installed on passenger 
seats. 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 conditions is November 12, 
2008. We must receive your comments by January 5, 2009.

ADDRESSES: You must mail two copies of your comments to: Federal 
Aviation

[[Page 70258]]

Administration, Transport Airplane Directorate, Attn: Rules Docket 
(ANM-113), Docket No. NM394, 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. NM394. 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: Dan Jacquet, FAA, Airframe and Cabin 
Safety Branch, ANM-115, Transport Airplane Directorate, 1601 Lind 
Avenue, SW., Renton, Washington 98057-3356; telephone (425) 227-2676; 
facsimile (425) 227-1320.

SUPPLEMENTARY INFORMATION: The FAA has determined that notice and 
opportunity for prior public comment hereon are impracticable because 
these procedures would significantly delay issuance of the design 
approval and thus delivery of the affected aircraft. 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 
about 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 based on the comments we receive.
    If you want us to let you know we received your comments on these 
special conditions, send us a pre-addressed, stamped postcard on which 
the docket number appears. We will stamp the date on the postcard and 
mail it back to you.

Background

    On September 2, 2008, Airbus, 1 Rond-Point Maurice Bellonte, 31707 
Blagnac, Cedex, France, applied for an amendment to Type Certificate 
No. A28NM to install the AmSafe Aviation Inflatable Restraint (AAIR) 
for head injury protection on passenger seats on Airbus A318, A319, 
A320 and A321 series airplanes. The AAIR is designed to limit passenger 
forward excursion in the event of an accident, thus reducing the 
potential for head injury (and head entrapment).
    The AAIR behaves like an automotive inflatable airbag except that 
the airbag is integrated into the passenger restraint system and 
inflates away from the seated passenger. While inflatable airbags are 
standard in the automotive industry, the use of an inflatable passenger 
restraint system is novel for commercial aviation.
    Title 14, Code of Federal Regulations (14 CFR) 25.785 requires that 
passengers be protected from head injury by either the elimination of 
any injurious object within the striking radius of the head or by 
padding. Traditionally, compliance has required either a setback of 35 
inches from any bulkhead, front seat or other rigid interior feature or 
padding where a setback was not practical. The relative effectiveness 
of these two means of injury protection was not quantified. The 
adoption of Amendment 25-64 to 14 CFR part 25, specifically Sec.  
25.562, created a new standard for protection from head injury. Airbus 
elected to comply with Sec.  25.562, except for Sec.  25.562(c)(5) 
(protection from head injury) and Sec.  25.562(c)(6) (protection from 
femur injury), for the Airbus A318, A319, and A321 series airplanes. 
The pertinent parts of Sec.  25.562 for these airplanes require that 
dynamic tests be conducted for each seat type installed in the 
airplane, and that each seat type meets certain performance measures. 
Although the head injury protection requirements of Sec.  25.562(e)(5) 
are not part of the certification basis for the affected airplanes, it 
is relevant for future compliance with Sec.  121.311(j). This 
regulation will require full compliance with Sec.  25.562 for airplanes 
manufactured on or after October 27, 2009.
    Because Sec. Sec.  25.562 and 25.785 do not adequately address 
seats with AAIRs, the FAA recognizes that we need to develop 
appropriate pass/fail criteria that do address the safety of occupants 
of those seats. These special conditions are applicable to inflatable 
restraint systems in general. However, because this initial application 
is for the AAIR, the following discussion refers specifically to the 
AAIR.
    The AAIR has two potential advantages over other means of head 
impact protection. The first is that it can provide significantly 
greater protection than would be expected with energy-absorbing pads; 
the second is that 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 part 25 standards.
    On the other hand, AAIRs are active systems and must 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 potential disadvantages 
in order to develop standards that will provide an equivalent level of 
safety to that intended by the regulations.
    There are two primary safety concerns with the use of AAIRs: (1) 
They perform properly under foreseeable operating conditions, and (2) 
they do not perform in a way that 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 AAIR 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. Airbus 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 
(occurring less than 10-9 per flight hour). The effect of an 
inadvertent deployment on a passenger sitting or standing close to the 
AAIR must also be considered. 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 
necessary.

[[Page 70259]]

    Other outside influences are lightning and high intensity radiated 
fields (HIRF). Since the sensors that trigger deployment are 
electronic, they must be protected from the effects of these threats. 
Existing regulations regarding lightning (Sec.  25.1316) and HIRF 
(Sec.  25.1317) are applicable in lieu of any other lightning and HIRF 
special conditions that have been adopted for the affected airplanes.
    For the purposes of compliance, if inadvertent deployment could 
cause a hazard to the airplane, the AAIR is considered a critical 
system; if inadvertent deployment could cause injuries to persons, the 
AAIR is considered an essential system. Finally, the AAIR installation 
should be protected from the effects of fire, so that an additional 
hazard is not created by, for example, a rupture of a pyrotechnic 
squib.
    In order to be an effective safety system, the AAIR must function 
properly and must not introduce any additional hazards to occupants as 
a result of its functioning. There are several areas where the AAIR 
differs from traditional occupant protection systems, and requires 
special conditions to ensure adequate performance.
    Because the AAIR is essentially a single use device, there is the 
potential that it could deploy under crash conditions that are not 
sufficiently severe as to require head injury protection from the AAIR. 
Since an actual crash is frequently composed of a series of impacts 
before the airplane comes to rest, this could render the AAIR 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 protection according to the severity of the impact. 
Therefore, the AAIR installation should be such that the AAIR will 
provide protection when it is required and will not expend its 
protection when it is not needed. There is no requirement for the AAIR 
to provide protection for multiple impacts, where more than one impact 
would require protection.
    Since each passenger'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 considering that unoccupied seats may have AAIR that are 
active.
    Since there is a wide range in the size of passengers, the AAIR 
must be effective over the entire range. The FAA has historically 
considered the range from the fifth percentile female to the ninety-
fifth percentile male as the range of passengers to take into account. 
In this case, the FAA is proposing consideration of an even broader 
range of passengers, due to the nature of the AAIR installation and its 
close proximity to the passenger. In a similar vein, passengers may 
assume the brace position for those accidents where an impact is 
anticipated. Test data indicate that passengers in the brace position 
do not require supplemental protection, so that it will not be 
necessary to show that the AAIR will enhance the brace position. 
However, the AAIR must not introduce a hazard in that case by deploying 
into the seated, braced passenger.
    Another area of concern is the use of seats occupied by children, 
whether lap-held, in approved child safety seats, or occupying the seat 
directly. 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 an appropriate limitation on 
usage.
    Since the AAIR 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 a means of protection in a 
crash or after a crash, 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 AAIR 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 AAIR would be 
deflated at the time that persons would be trying to leave their seats. 
Nonetheless, it is considered appropriate to specify a time interval 
after which the AAIR may not impede rapid egress. Ten seconds has been 
chosen as a reasonable time, since it corresponds to the maximum time 
allowed for an exit to be openable. In actuality, it is unlikely that 
an exit would be prepared this quickly in an accident severe enough to 
warrant deployment of the AAIR, and the AAIR will likely deflate much 
quicker than ten seconds.
    The manufacturers of the inflatable lap belts have been unable thus 
far to develop a fabric that meets the inflation requirements for the 
bag and the flammability requirements of Part I(a)(1)(ii) of appendix F 
of part 25. The fabrics that have been developed that meet the 
flammability requirements 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 and has acceptable deployment 
characteristics.
    Finally, it should be noted that the special conditions are 
applicable to the AAIR 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 a separate finding and must consider the combined effects of all 
such systems installed.

Type Certification Basis

    Under the provisions of Sec.  21.101, Airbus must show that the 
A318, A319, A320 and A321 series airplanes, as changed, continue to 
meet the applicable provisions of the regulations incorporated by 
reference in Type Certificate No. A28NM 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 for each individual airplane model are defined within Type 
Certificate Data Sheet (TCDS) A28NM.
    In addition, the certification basis includes other regulations and 
special conditions that are not pertinent to these special conditions.
    If the Administrator finds that the applicable airworthiness 
regulations (i.e., 14 CFR part 25) do not contain adequate or 
appropriate safety standards for the Airbus A318, A319, A320 and A321 
series airplanes, because of a novel or unusual design feature, special 
conditions are prescribed under the provisions of Sec.  21.16.
    In addition to the applicable airworthiness regulations and special 
conditions, each airplane model 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 Sec.  11.19, under 
Sec.  11.38 and they become part of the type certification basis under 
Sec.  21.101.
    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 novel or 
unusual design feature, or should any other model included on the same 
type certificate be modified to incorporate the same novel or unusual 
design

[[Page 70260]]

feature, the special conditions would also apply to the other model.

Novel or Unusual Design Features

    The Airbus A318, A319, A320 and A321 series airplanes will 
incorporate the following novel or unusual design features: These 
airplanes as modified by Airbus will have a passenger restraint system 
that contains an integrated inflatable airbag device installed on 
passenger seats. The AAIR will be installed to reduce the potential for 
head injury in the event of an accident. The AAIR works like an 
automotive airbag, except that the airbag is integrated with the 
passenger restraint system. The AAIR is considered a novel design for 
transport category airplanes and was not considered as part of the 
original type certification basis.
    Section 25.785 states the performance criteria for head injury 
protection in objective terms. However, none of these criteria are 
adequate to address the specific issues raised concerning seats with 
AAIR. The FAA has therefore determined that, in addition to the 
requirements of 14 CFR part 25, special conditions are needed to 
address requirements particular to installation of seats with AAIR.
    Accordingly, in addition to the passenger injury criteria specified 
in Sec.  25.785, these special conditions are adopted for the Airbus 
A318, A319, A320 and A321 series airplanes equipped with AAIR. Other 
conditions may be developed, as needed, based on further FAA review and 
discussions with the manufacturer and civil aviation authorities.

Discussion

    From the standpoint of a passenger safety system, the airbag is 
unique in that it is both an active and entirely autonomous device. 
While the automotive industry has good experience with airbags, the 
conditions of use and reliance on the airbag as the sole means of 
injury protection are quite 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 activation system.
    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 
airbags is a relatively rare event, and because the consequences of an 
inadvertent activation are potentially quite severe, these latter 
requirements are probably the more rigorous from a design standpoint.

 Applicability

    As discussed above, these special conditions are applicable to 
Airbus A318, A319, A320 and A321 series airplanes. Should Airbus apply 
at a later date for a change to type certificate to include another 
model incorporating the same novel or unusual design feature, the 
special conditions would apply to that model as well.

Conclusion

    This action affects only certain novel or unusual design features 
on Airbus A318, A319, A320 and A321 series airplanes. It is not a rule 
of general applicability.
    The substance of these special conditions has been subjected to the 
notice and comment period in several prior instances and has been 
derived without substantive change from those previously issued. It is 
unlikely that prior public comment would result in a significant change 
from the substance contained herein. For this reason and because a 
delay would significantly affect the certification of the airplane, 
which is imminent, the FAA has determined that prior public notice and 
comment are unnecessary and impracticable and that good cause exists 
for adopting these special conditions upon issuance. The FAA is 
requesting comments to allow interested persons to submit views that 
may not have been submitted in response to the prior opportunities for 
comment described above.

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

0
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 Airbus A318, A319, A320 and A321 
series airplanes, as modified by installation of inflatable restraints.
    1. Seats with inflatable restraints. It must be shown that the 
inflatable restraints will deploy and provide protection under crash 
conditions where it is necessary to prevent serious head injury or head 
entrapment. 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 restraints must provide a consistent approach to 
energy absorption throughout that range. 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 restraints 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 restraints from being 
either incorrectly buckled or incorrectly installed such that the 
inflatable restraints 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 restraints 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 restraints must not introduce 
injury mechanisms to 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 
restraints, 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 restraints will not impede 
rapid egress of occupants 10 seconds after its deployment.
    9. If lithium non-rechargeable batteries are used to power the 
inflatable restraints, the batteries must be DO-227 and UL compliant. 
However, if rechargeable lithium batteries are used,

[[Page 70261]]

additional special conditions may apply.
    10. The inflatable restraints must function properly after loss of 
normal airplane electrical power and after a transverse separation of 
the fuselage at the most critical location. A separation at the 
location of the lap belt does not have to be considered.
    11. It must be shown that the inflatable restraints will not 
release hazardous quantities of gas or particulate matter into the 
cabin.
    12. The inflatable restraints installation must be protected from 
the effects of fire such that no hazard to occupants will result.
    13. The system must be protected from lightning and HIRF. The 
threats specified in Special Conditions No. 25-ANM-23 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.
    14. There must be a means for a crewmember to verify the integrity 
of the inflatable restraints activation system prior to each flight or 
it must be demonstrated to reliably operate between inspection 
intervals.
    15. 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 November 12, 2008.
Stephen P. Boyd,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E8-27541 Filed 11-19-08; 8:45 am]
BILLING CODE 4910-13-P