[Federal Register Volume 67, Number 231 (Monday, December 2, 2002)]
[Proposed Rules]
[Pages 71490-71493]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-30325]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 23

[Docket No. CE191]; Notice No. 23-03-022-SC]


Special Conditions: Air Tractor Incorporated, Models AT-401, AT-
402, AT-502, AT-602, and AT-802; Seats With Goodrich Aircraft Interior 
Products (AIP) Four-Point Inflatable Restraints

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed special conditions.

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SUMMARY: This notice proposes special conditions for the following Air 
Tractor AT series airplanes; AT-401, AT-402, AT-502, AT-602, and AT-
802. These airplanes, as modified by Goodrich Aircraft Interior 
Products, will have novel and unusual design features associated with a 
four-point inflatable (airbag) restraint. The applicable airworthiness 
regulations do not contain adequate or appropriate safety standards for 
this design feature. These proposed 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: Comments must be received on or before January 2, 2003.

ADDRESSES: Comments on this proposal may be mailed in duplicate to: 
Federal Aviation Administration (FAA), Regional Counsel, ACE-7, 
Attention: Rules Docket, Docket No. CE191, 901 Locust, Room 506, Kansas 
City, Missouri 64106, or delivered in duplicate to the Regional Counsel 
at the above address. Comments must be marked: CE191. Comments may be 
inspected in the Rules Docket weekdays, except Federal holidays, 
between 7:30 a.m. and 4 p.m.

FOR FURTHER INFORMATION CONTACT: 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.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of 
these proposed special conditions by submitting such written data, 
views, or arguments, as they may desire. Communications should identify 
the regulatory docket or notice number and be submitted in duplicate to 
the address specified above. All communications received on or before 
the closing date for comments will be considered by the Administrator. 
The proposals described in this notice may be changed in light of the 
comments received. All comments received will be available in the Rules 
Docket for examination by interested persons, both before and after the 
closing date for comments. A report summarizing each substantive public 
contact with FAA personnel concerning this rulemaking will be filed in 
the docket. Persons wishing the FAA to acknowledge receipt of their 
comments submitted in response to this notice must include with those 
comments a self-addressed, stamped postcard on which the following 
statement is made:

[[Page 71491]]

``Comments to CE191.'' The postcard will be date stamped and returned 
to the commenter.

Background

    On March 8, 2002, Goodrich Aircraft Interior Products (GAIP), 1275 
N. Newport Road, Colorado Springs, CO 80916-2779, applied for a 
supplemental type certificate to install four-point inflatable 
restraints in Air Tractor AT series airplanes AT-401, AT-402, AT-502, 
AT-602, and AT-802. The Air Tractor AT series airplanes comprise a 
group of agricultural aircraft certificated under 14 Code of Federal 
Regulations (CFR) 21.25, Restricted Category. These airplanes are 
intended for single pilot operation, sharing the same seating 
environment and seat-to-aircraft attachments. Therefore, the inflatable 
restraint system proposed by GAIP can be used with each Air Tractor 
model listed. The inflatable restraint system limits occupant forward 
excursion in case of an accident, while forming a protective cushion 
around the sides of the occupant's head. This will reduce the potential 
for head and torso injury. The inflatable four-point restraint behaves 
in a manner that is similar to an automotive airbag, but in this case, 
the airbags are integrated into each shoulder harness, inflating away 
from the occupant. The lapbelt portion of this four-point restraint is 
conventional and does not inflate. While airbags and inflatable 
restraints are standard in the automotive industry, the use of an 
inflatable four-point restraint is novel for agricultural operations.
    Agricultural airplanes, like the Air Tractor AT series, contain 
many elements of a cashworthy design first described in a 1949 Cornell 
University study. These elements include a cockpit structure that 
encases the pilot, crushable structure forward of and underneath the 
pilot, a low-positioned instrument panel which the pilot's head would 
not strike, required use of a helmet, and other features such as a 
strong harness system and an energy absorbing seat. These design 
features have contributed to the excellent safety record of 
agricultural airplanes. The fatality rates experienced by the 
agricultural airplane fleet are roughly half of that experienced by the 
general aviation fleet. This lower fatality rate is in spite of a 
higher overall accident rate with respect to that of general aviation.
    In consideration of the excellent fatality record of agricultural 
airplanes in general, and the Air Tractor AT series in particular, the 
FAA has determined that installation of a four-point inflatable 
restraint must be accomplished on the basis of not lowering the current 
level of safety of the AT-401, AT-402, AT-502, AT-602, and AT-802. 
Therefore, the FAA considers that installation of an inflatable 
restraint as having two primary safety concerns:
    [sbull] That it perform properly under foreseeable operating 
conditions, and;
    [sbull] That it not perform in a manner or at such times as would 
constitute a hazard to the airplane or occupants.

The latter point has the potential to be the more rigorous of the 
requirements. Agricultural operations typically occur at very low 
altitudes. An unexpected deployment while conducting these operations 
may result in an unsafe condition in flight. 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 altitude. The FAA has considered 
this when establishing the special conditions.
    GAIP has developed a ``Smartbelt'' Four-Point Manually Adjusting 
Restraint seatbelt with an integrated inflatable airbag device. This 
inflatable restraint will rely on electronic sensors for firing and 
pyrotechnic charges for activation. 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. GAIP must 
substantiate that the effects of an inadvertent deployment in flight 
are not a hazard to the airplane. In addition, the operating conditions 
of agricultural aircraft can generate a large amount of cumulative wear 
and tear on the 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. Ultimately, because of the effects of this cumulative 
damage, a life limit must be established for the restraint system 
design.
    There are additional factors to be considered to minimize the 
chances of inadvertent deployment. Agricultural airplanes are exposed 
to an extreme operating environment. The effect of this environment on 
inadvertent deployment of the restraint must be understood. The 
qualification testing of the firing hardware/software must consider the 
following:
    [sbull] The airplane vibration levels appropriate for agricultural 
airplanes, and
    [sbull] 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). Since the sensors that trigger 
deployment are electronic, they must be protected from the effects of 
this threat. For complying with HIRF requirements, the inflatable 
system is considered a critical system if its deployment could have a 
hazardous effect on the airplane; otherwise, it is considered an 
essential system. Finally, 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 pyrotechnic squib.
    While restricted category aircraft need not demonstrate compliance 
to 14 CFR part 23, Sec.  23.562, there are many elements of Sec.  
23.562 that can be used to ensure an adequate level of protection 
during an emergency landing. These elements include an appropriate 
crash pulse and various injury pass/fail criteria. Therefore, the 
inflatable seatbelt must undergo qualification tests of the firing 
hardware/software for the 26 G deceleration pulse defined under Sec.  
23.562(b)(2). When the inflatable portion of the restraint is subjected 
to, and operates as a result of the 26 G deceleration pulse, it must be 
shown that deployment of the device will not be a hazard to the 
occupant. This can be accomplished by assuring that the 4-point 
restraint does not ride above the pelvis into the abdomen, as required 
by Sec.  23.562(c)(4). This also includes satisfying the maximum 
harness loads permitted by Sec.  23.562(c)(6).
    Given the level of safety of the current Air Tractor harness, the 
inflatable restraint must show that it will offer an equivalent level 
of protection in the event the inflatable portion fails to deploy. In 
the event of an inadvertent deployment, the restraint must still have 
the same strength capability after the inflatable portion of the 
restraint has been deployed. There is no requirement for the inflatable 
portion of the restraint to offer protection during multiple impacts, 
where more than one impact would require protection.
    The inflatable seatbelt system must deploy and provide protection 
under crash conditions where it is necessary to prevent serious injury. 
In support of this operational capability, there must be a means to 
verify the integrity of this system before each flight. As an option, 
GAIP can establish inspection intervals

[[Page 71492]]

where they have demonstrated the system to be reliable between these 
intervals.
    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. In addition, the operation of this 
restraint must be transparent to the user. Therefore, the design must 
prevent the inflatable seatbelt from being incorrectly buckled and/or 
installed such that the airbag would not properly deploy. In addition, 
when deployment does occur, there must not be a release of hazardous 
quantities of gas or particulate matter into the cockpit area.
    Finally, the inflatable restraint is likely to have a large volume 
displacement, where the inflated bag could 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 restrain 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, Goodrich Aircraft Interior 
Products must show that the Air Tractor AT series airplanes AT-401, AT-
402, AT-502, AT-602, and AT-802, as changed, continue to meet the 
applicable provisions of the regulations incorporated by reference in 
Type Certificate No. A17SW (for AT-401, AT-402, and AT-502) and Type 
Certificate No. A19SW (for AT-602 and AT-802) 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. A17SW are 
as follows:
    [sbull] For models AT-401, AT-401A, and AT-401B, Sec.  21.25(a)(1), 
14 CFR part 23 through 23-9, and Appendix B, CAM 8. For models AT-402, 
AT-402A, AT-402B, AT-502, AT-502A, and AT-502B, Sec.  21.25(a), (b)(1), 
(b)(2), Amendments 23-1 through 23-9, Appendix B, CAM 8, and additional 
turbine engine requirements that are of no relevance to the special 
conditions.
    The regulations incorporated by reference in Type Certificate No. 
A19SW are as follows:
    [sbull] For model AT-602, 14 CFR part 23 through Amendment 23-42. 
For model AT-802, 14 CFR part 23 through Amendment 23-42, plus Sec.  
21.25(b)(1), (b)(2), and (b)(7). For model AT-802A, 14 CFR part 23 
through Amendment 42, plus Sec.  21.25(b)(1), (b)(2), and (b)(7).

For each model 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 GAIP inflatable restraint as 
installed on Air Tractor models AT-401, AT-402, AT-502, AT-602, and AT-
802 because of a novel or unusual design feature. Therefore, special 
conditions are prescribed under the provisions of Sec.  21.6.
    In addition to the applicable airworthiness regulations and special 
conditions, Air Tractor models equipped with the GAIP inflatable 
restraint must comply with the fuel vent and exhaust emission 
requirements of 14 CFR part 34.
    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(b)(2).
    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(a)(1).

Novel or Unusual Design Features

    Air Tractor Models AT-401, AT-402, AT-502, AT-601, and AT-802 will 
incorporate the following novel or unusual design features.

The Goodrich Aircraft Interior Products ``Smartbelt'' Four-Point 
Manually Adjusting Restraint Seatbelt

    The purpose of the inflatable airbag seatbelt is to reduce the 
potential for injury in the event of an accident. In a severe impact, 
airbags will deploy out of the shoulder harnesses portion of the 
restraint, in a manner similar to an automotive airbag. These airbags 
will restrain the motion of the occupant during a severe impact and 
offer some protection to the head of the occupant. The restraint will 
rely on electronic sensors for firing, and pyrotechnic charges for 
activation.
    The CFR states 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 in 
agricultural airplanes. 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 inflatable four-point 
restraints.
    Accordingly, these special conditions are adopted for Air Tractor 
Models AT-401, AT-402, AT-502, AT-602, and AT-802 equipped with the 
Goodrich Aircraft Interior Products four-point inflatable restraint. 
Other conditions may be developed, as needed, based on further FAA 
review and discussions with the manufacturer and civil aviation 
authorities.
    The FAA has determined that this project will be accomplished on 
the basis of not lowering the current level of safety for these Air 
Tractor models. The FAA recognizes that the current Air Tractor 
occupant restraint system has an excellent safety record. The FAA has 
considered the installation of inflatable restraints as having two 
primary safety concerns: (1) That they perform properly under 
foreseeable operating conditions; (2) that they not perform in a manner 
or at such times as would constitute a hazard to the airplane or 
occupants.

Applicability

    As discussed above, these special conditions are applicable to the 
Air Tractor model series AT-401, AT-402, AT-502, AT-602, and AT-802 
equipped with the GAIP four-point inflatable restraint. Should GAIP 
apply at a later date for a supplemental type certificate to modify any 
other model on Type Certificate numbers A17SW or AW19SW 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(a)(1).

Conclusion

    This action affects only certain novel or unusual design features 
on Air Tractor model series AT-401, AT-402, AT-502, AT-602, and AT-802 
airplanes. 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.

[[Page 71493]]

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 or 21.17 for TC; and 14 CFR 11.38 and 11.19.

The Proposed Special Conditions

    The FAA has determined that this project will be accomplished on 
the basis of not lowering the current level of safety for the Air 
Tractor Model AT-401, -402, -502, -602, and -802 series occupant 
restraint design. Accordingly, the (FAA) proposes the following special 
conditions as part of the type certification basis for Air Tractor 
series airplanes AT-401, AT-402, AT-502, AT-602, and AT-802 modified by 
Goodrich Aircraft Interior Products.

4-Point Inflatable Restraints for Agricultural Airplanes

    1. It must be shown that the inflatable seatbelt will deploy and 
provide protection under crash conditions where it is necessary to 
prevent serious injury. A dynamic test is required to verify that the 
system operates as intended when subjected to the 26 G deceleration 
pulse described in Sec.  23.562(b)(2). The dynamic test need only be 
performed using a 50 percentile male ATD.
    2. The means of protection must take into consideration a range of 
stature from a 5 percentile female to a 95 percentile male. The 
inflatable seatbelt must provide a consistent level of energy 
absorption throughout that range.
    3. The design must prevent the inflatable seatbelt from either 
being incorrectly buckled or incorrectly installed, or both, such that 
the airbag would not properly deploy.
    4. It must be shown that an inadvertent deployment does not cause 
an unsafe condition (or hazard to the airplane). Consideration needs to 
be given 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. The seat belt must have the same 
strength capability after the inflatable portion of the restraint has 
been deployed.
    5. It must be shown that deployment of the device is not hazardous 
to the occupant. In addition, the seated occupant must not be injured 
as established by criteria in Sec.  23.562 as a result of the 
inflatable seatbelt deployment, including keeping the lap belt located 
on the pelvis.
    6. It must be shown that the inflatable seatbelt will not impede 
rapid egress of the occupant 10 seconds after its deployment.
    7. For the purpose of complying with HIRF and lightning 
requirements, the inflatable seatbelt system is considered a ``critical 
system'' if its deployment could have a hazardous effect on the 
airplane; otherwise, it is considered an ``essential'' system.
    8. It must be shown that the inflatable seatbelt will not release 
hazardous quantities of gas or particulate matter into the cabin.
    9. The inflatable seatbelt installation must be protected from the 
effects of fire such that no hazard to occupants will result.
    10. There must be a means to verify the integrity of the inflatable 
seatbelt activation system before each flight or it must be 
demonstrated to reliably operate between inspection intervals.
    11. A life limit needs to be established for appropriate system 
designs.
    12. Qualification testing of the internal firing mechanism must be 
accomplished using the vibration levels appropriate for an agricultural 
airplane.

Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 02-30325 Filed 11-29-02; 8:45 am]
BILLING CODE 4910-13-M