[Federal Register Volume 69, Number 235 (Wednesday, December 8, 2004)]
[Rules and Regulations]
[Pages 70885-70887]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-26979]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 23

[Docket No. CE210; Special Conditions No. 23-153-SC]


Special Conditions: AMSAFE, Incorporated, Sky International A1, 
A1A, A1B, Inflatable Five-Point Seatbelt Airbag Restraint

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions.

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SUMMARY: These special conditions are issued for an AMSAFE, Inc. 
Inflatable Five-Point Seatbelt Airbag Restraint on Sky International 
models A1, A1A, and A1B. These airplanes, as modified by AMSAFE, Inc. 
will have novel and unusual design features associated with the upper-
torso restraint portions of the 5-point safety belt, which contains an 
integrated airbag device. The applicable airworthiness regulations do 
not contain adequate or appropriate safety standards for this design 
feature. These special conditions contain the additional safety 
standards the Administrator considers necessary to establish a level of 
safety equivalent to that established by the existing airworthiness 
standards.

DATES: Effective Date: The effective date of these special conditions 
is November 24, 2004.

FOR FURTHER INFORMATION CONTACT: Mr. Pat Mullen, Federal Aviation 
Administration, Aircraft Certification Service, Small Airplane 
Directorate, ACE-111, 901 Locust, Kansas City, Missouri, 816-329-4128, 
fax 816-329-4090, e-mail: [email protected].

SUPPLEMENTARY INFORMATION:

Background

    On January 15, 2004, AMSAFE, Inc. Aviation Inflatable Restraints 
Division, 1043 North 47th Avenue, Phoenix, AZ 85043, applied for a 
supplemental type certificate for the installation of a five-point 
safety belt restraint system incorporating an inflatable airbag for the 
pilot and co-pilot seats of the Sky International model A1, A1A, and 
A1B airplanes. Models A1, A1A, and A1B are single engine, two-place 
airplanes, arranged in a tandem configuration.
    The inflatable restraint system is a five-point safety belt 
restraint system consisting of a lapbelt and dual shoulder harnesses. 
An inflatable airbag is attached to one of the shoulder harnesses, and 
the other shoulder harness is of conventional construction. The 
inflatable portion of the restraint system will rely on sensors to 
electronically activate the inflator for deployment. The inflatable 
restraint system will be installed on both the pilot and co-pilot 
seats.
    In the event of an emergency landing, the airbag will inflate and 
provide a protective cushion between the occupant's head and structure 
within the airplane cockpit. This will reduce the potential for head 
and torso injury. The inflatable restraint behaves in a manner that is 
similar to an automotive airbag, but in this case, the airbag is 
integrated into one of the shoulder harnesses. While airbags and 
inflatable restraints are standard in the automotive industry, the use 
of an inflatable five-point restraint system is novel for general 
aviation operations.
    The FAA has determined that this project will be accomplished on 
the basis of providing the same current level of safety of the Sky 
International A1, A1A, and A1B occupant restraint systems. The FAA has 
two primary safety concerns with the installation of airbags or 
inflatable restraints:
     That they perform properly under foreseeable operating 
conditions; and
     That they do not perform in a manner or at such times to 
impede the pilot's ability to maintain control of the airplane or 
constitute a hazard to the airplane or occupants.
    The latter point has the potential to be the more rigorous of the 
requirements. An unexpected deployment while conducting the takeoff or 
landing phases of flight may result in an unsafe condition. The 
unexpected deployment may either startle the pilot, or generate a force 
sufficient to cause a sudden movement of the control stick. Either 
action could result in a loss of control of the airplane, the 
consequences of which are magnified due to the low operating altitudes 
during these phases of flight. The FAA has considered this when 
establishing the special conditions.
    The inflatable restraint system relies on sensors to electronically 
activate the inflator for deployment. These sensors could be 
susceptible to inadvertent activation, causing deployment in a 
potentially unsafe manner. The consequences of an inadvertent 
deployment must be considered in establishing the reliability of the 
system. AMSAFE, Inc. must show that the effects of an inadvertent 
deployment in flight are not a hazard to the airplane or that an 
inadvertent deployment is extremely improbable. In addition, any 
general aviation aircraft can generate a large amount of cumulative 
wear and tear on a restraint system. It is likely that the potential 
for inadvertent deployment increases as a result of this cumulative 
damage. Therefore, the impact of wear and tear on inadvertent 
deployment must be considered. Due to the effects of this cumulative 
damage, a life limit must be established for the appropriate system 
components in the restraint system design.
    There are additional factors to be considered to minimize the 
chances of inadvertent deployment. General aviation airplanes are 
exposed to a unique operating environment, since the same airplane may 
be used by both experienced and student pilots. The effect of this 
environment on inadvertent deployment must be understood. Therefore, 
qualification testing of the firing hardware/software must consider the 
following:
     The airplane vibration levels appropriate for a general 
aviation airplane; and
     The inertial loads that result from typical flight or 
ground maneuvers, including gusts and hard landings.
    Any tendency for the firing mechanism to activate as a result of 
these loads or acceleration levels is unacceptable.
    Other influences on inadvertent deployment include high intensity 
electromagnetic fields (HIRF) and lightning. Since the sensors that 
trigger deployment are electronic, they must be protected from the 
effects of these threats. To comply with HIRF and lightning 
requirements, the AMSAFE, Inc. inflatable restraint system is 
considered a critical system, since its inadvertent deployment could 
have a hazardous effect on the airplane.
    Given the level of safety of the current Sky International A1, A1A, 
and A1B occupant restraints, the inflatable restraint system must show 
that it will offer an equivalent level of protection in the event of an 
emergency landing. In the event of an inadvertent deployment, the 
restraint must still be at least as strong as a Technical Standard 
Order certificated belt and dual shoulder harnesses. There is no 
requirement for

[[Page 70886]]

the inflatable portion of the restraint to offer protection during 
multiple impacts, where more than one impact would require protection.
    The inflatable restraint system must deploy and provide protection 
for each occupant under a crash condition where it is necessary to 
prevent serious head injury. The seats of the models A1, A1A, and A1B 
are not certificated to the requirements of Sec.  23.562, and it is not 
known if they would remain intact following exposure to the crash pulse 
identified in Sec.  23.562. Therefore, the test crash pulse used to 
satisfy this requirement may have a peak longitudinal deceleration 
lower than that required by Sec.  23.562. However, the test pulse onset 
rate (deceleration divided by time) must be equal to or greater than 
the onset rate of the pulse described in Sec.  23.562. This will 
demonstrate that the crash sensor will trigger when exposed to a 
rapidly applied deceleration, like an actual crash event.
    It is possible a wide range of occupants will use the inflatable 
restraint. Thus, the protection offered by this restraint should be 
effective for occupants that range from the fifth percentile female to 
the ninety-fifth percentile male. Energy absorption must be performed 
in a consistent manner for this occupant range.
    In support of this operational capability, there must be a means to 
verify the integrity of this system before each flight. As an option, 
AMSAFE, Inc. can establish inspection intervals where they have 
demonstrated the system to be reliable between these intervals.
    It is possible that an inflatable restraint will be ``armed'' even 
though no occupant is using the seat. While there will be means to 
verify the integrity of the system before flight, it is also prudent to 
require that unoccupied seats with active restraints not constitute a 
hazard to any occupant. This will protect any individual performing 
maintenance inside the cockpit while the aircraft is on the ground.
    In addition, the design must prevent the inflatable seatbelt from 
being incorrectly buckled and/or installed such that the airbag would 
not properly deploy. As an alternative, AMSAFE, Inc. may show that such 
deployment is not hazardous to the occupant, and will still provide the 
required protection.
    The cockpits of the models A1, A1A, and A1B are confined areas, and 
the FAA is concerned that noxious gasses may accumulate in the event of 
restraint deployment. When deployment does occur, either by design or 
inadvertently, there must not be a release of hazardous quantities of 
gas or particulate matter into the cockpit.
    An inflatable restraint should not increase the risk already 
associated with fire. Therefore, the inflatable restraint should be 
protected from the effects of fire, so that an additional hazard is not 
created by, for example, a rupture of the inflator.
    Finally, the airbag is likely to have a large volume displacement, 
and possibly impede the egress of an occupant. Since the bag deflates 
to absorb energy, it is likely that the inflatable restraint would be 
deflated at the time an occupant would attempt egress. However, it is 
appropriate to specify a time interval after which the inflatable 
restraint may not impede rapid egress. Ten seconds has been chosen as 
reasonable time. This time limit will offer a level of protection 
throughout the impact event.

Type Certification Basis

    Under the provisions of Sec.  21.101, AMSAFE, Inc. must show that 
the Sky International models A1, A1A, and A1B, as changed, continue to 
meet the applicable provisions of the regulations incorporated by 
reference in Type Certificate No. A22NM 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. A22NM are as follows:
    Part 23 of the Federal Aviation Regulations dated February 1, 1965, 
as amended by 23-1 through 23-31 (normal category) and FAR 36 amended 
through 36-12.
    FAR 21 amended through 21-57.
    For the models listed above, the certification basis also includes 
all exemptions, if any; equivalent level of safety findings, if any; 
and the special conditions adopted by this rulemaking action.
    The Administrator has determined that the applicable airworthiness 
regulations (i.e., part 23 as amended) do not contain adequate or 
appropriate safety standards for the AMSAFE, Inc. inflatable restraint 
as installed on these Sky International models because of a novel or 
unusual design feature. Therefore, special conditions are prescribed 
under the provisions of Sec.  21.16.
    Special conditions, as appropriate, as defined in Sec.  11.19, are 
issued in accordance with Sec.  11.38, and become part of the type 
certification basis in accordance with Sec.  21.101.
    Special conditions are initially applicable to the model for which 
they are issued. Should the applicant apply for a supplemental type 
certificate to modify any other model included on the same type 
certificate to incorporate the same novel or unusual design feature, 
the special conditions would also apply to that model under the 
provisions of Sec.  21.101.

Novel or Unusual Design Features

    The Sky International models A1, A1A, and A1B will incorporate the 
following novel or unusual design feature:
    The AMSAFE, Inc. Five-Point Safety Belt Restraint System 
incorporating an inflatable airbag for the pilot and co-pilot seats. 
The purpose of the airbag is to reduce the potential for injury in the 
event of an accident. In a severe impact, an airbag will deploy from 
one shoulder harness, in a manner similar to an automotive airbag. The 
airbag will deploy between the head of the occupant and cockpit 
structure. This will, therefore, provide some protection to the head of 
the occupant. The restraint will rely on sensors to electronically 
activate the inflator for deployment.
    The Code of Federal Regulations state performance criteria for 
seats and restraints in an objective manner. However, none of these 
criteria are adequate to address the specific issues raised concerning 
inflatable restraints. Therefore, the FAA has determined that, in 
addition to the requirements of part 21 and part 23, special conditions 
are needed to address the installation of this inflatable restraint.
    Accordingly, these special conditions are adopted for the models 
A1, A1A, and A1B equipped with the AMSAFE, Inc. five-point inflatable 
restraint. Other conditions may be developed, as needed, based on 
further FAA review and discussions with the manufacturer and civil 
aviation authorities.

Discussion of Comments

    Notice of No. 23-04-01-SC for the AMSAFE, Inc. Inflatable Five-
Point Seatbelt Airbag Restraint on Sky International models A1, A1A, 
and A1B airplanes was published in the Federal Register on September 
14, 2004, 69FR55367. No comments were received, and the special 
conditions are adopted as proposed.

Applicability

    As discussed above, these special conditions are applicable to the 
Sky International models A1, A1A, and A1B equipped with the AMSAFE, 
Inc. five-point inflatable restraint system. Should

[[Page 70887]]

AMSAFE, Inc. apply at a later date for a supplemental type certificate 
to modify any other model on Type Certificate number A22NM to 
incorporate the same novel or unusual design feature, the special 
conditions would apply to that model as well under the provisions of 
Sec.  21.101.

For Final Special Conditions Effective Upon Issuance

    Under standard practice, the effective date of final special 
conditions would be 30 days after the date of publication in the 
Federal Register; however, as the certification date for the AMSAFE, 
Inc. Inflatable Five-Point Seatbelt Airbag Restraint on Sky 
International models A1, A1A, and A1B is imminent, the FAA finds that 
good cause exists to make these special conditions effective upon 
issuance.

Conclusion

    This action affects only certain novel or unusual design features 
on the Sky International models A1, A1A, and A1B. It is not a rule of 
general applicability, and it affects only the applicant who applied to 
the FAA for approval of these features on the airplane.

List of Subjects in 14 CFR Part 23

    Aircraft, Aviation safety, Signs and symbols.

Citation

    The authority citation for these special conditions is as follows:

    Authority: 49 U.S.C. 106(g), 40113 and 44701; 14 CFR 21.16 and 
21.101 for STC; and 14 CFR 11.38 and 11.19.

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 Sky International models A1, A1A, 
as modified by AMSAFE, Inc. Five-Point Safety Belt Restraint System 
Incorporating an Inflatable Airbag for the Pilot and Co-pilot Seats of 
the Sky International models A1, A1A, and A1B.
    1. It must be shown that the inflatable lapbelt will deploy and 
provide protection under crash conditions where it is necessary to 
prevent serious head injuries. Compliance will be demonstrated using 
the deceleration pulse specified in Sec.  23.562, which may be modified 
as follows:
    a. The peak longitudinal deceleration may be reduced, however the 
onset rate of the deceleration must be equal to or greater than the 
crash pulse identified in Sec.  23.562.
    b. The peak longitudinal deceleration must be above the deployment 
threshold of the crash sensor, and equal to or greater than the forward 
static design longitudinal load factor required by the original 
certification basis of the airplane.
    The means of protection must take into consideration a range of 
stature from a 5th percentile female to a 95th percentile male. The 
inflatable restraint must provide a consistent approach to energy 
absorption throughout that range.
    2. The inflatable restraint must provide adequate protection for 
each occupant. In addition, unoccupied seats that have an active 
restraint must not constitute a hazard to any occupant.
    3. The design must prevent the inflatable restraint from being 
incorrectly buckled and/or incorrectly installed such that the airbag 
would not properly deploy. Alternatively, it must be shown that such 
deployment is not hazardous to the occupant and will provide the 
required protection.
    4. It must be shown that the inflatable restraint system is not 
susceptible to inadvertent deployment as a result of wear and tear or 
the inertial loads resulting from in-flight or ground maneuvers 
(including gusts and hard landings) that are likely to be experienced 
in service.
    5. It must be shown (or be extremely improbable) that an 
inadvertent deployment of the restraint system during the most critical 
part of the flight does not impede the pilot's ability to maintain 
control of the airplane or cause an unsafe condition (or hazard to the 
airplane). In addition, a deployed inflatable restraint must be at 
least as strong as a Technical Standard Order (C114) 5-point harness.
    6. It must be shown that deployment of the inflatable restraint 
system is not hazardous to the occupant or result in injuries that 
could impede rapid egress. This assessment should include occupants 
whose restraint is loosely fastened.
    7. It must be shown that an inadvertent deployment that could cause 
injury to a standing or sitting person is improbable.
    8. It must be shown that the inflatable restraint will not impede 
rapid egress of the occupants 10 seconds after its deployment.
    9. For the purposes of complying with HIRF and lightning 
requirements, the inflatable restraint system is considered a critical 
system since its deployment could have a hazardous effect on the 
airplane.
    10. It must be shown that the inflatable restraints will not 
release hazardous quantities of gas or particulate matter into the 
cabin.
    11. The inflatable restraint system installation must be protected 
from the effects of fire such that no hazard to occupants will result.
    12. There must be a means to verify the integrity of the inflatable 
restraint activation system prior to each flight or it must be 
demonstrated to reliably operate between inspection intervals.
    13. A life limit must be established for appropriate system 
components.
    14. Qualification testing of the internal firing mechanism must be 
performed at vibration levels appropriate for a general aviation 
airplane.

    Issued in Kansas City, Missouri on November 24, 2004.
James E. Jackson,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Services.
[FR Doc. 04-26979 Filed 12-7-04; 8:45 am]
BILLING CODE 4910-13-P