[Federal Register Volume 68, Number 137 (Thursday, July 17, 2003)]
[Proposed Rules]
[Pages 42315-42317]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-18071]


 ========================================================================
 Proposed Rules
                                                 Federal Register
 ________________________________________________________________________
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 This section of the FEDERAL REGISTER contains notices to the public of 
 the proposed issuance of rules and regulations. The purpose of these 
 notices is to give interested persons an opportunity to participate in 
 the rule making prior to the adoption of the final rules.
 
 ========================================================================
 

  Federal Register / Vol. 68, No. 137 / Thursday, July 17, 2003 / 
Proposed Rules  

[[Page 42315]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 23

[Docket No. CE197; Notice No. 23-03-01-SC]


Special Conditions: AMSAFE, Incorporated, Zenair Model CH2000, 
Inflatable Three-Point Self-Adjusting Restraint Safety Belt With an 
Integrated Inflatable Airbag Device

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed special conditions.

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SUMMARY: This notice proposes special conditions for the installation 
of an AMSAFE, Inc. Inflatable Three-Point Self-Adjusting Restraint 
Safety Belt with an Integrated Inflatable Airbag Device on the Zenair 
model CH2000. This airplane, as modified by AMSAFE, Inc. will have 
novel and unusual design features associated the lap belt portion of 
the safety belt containing an integrated airbag device. 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 August 18, 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. CE197, 901 Locust, Room 506, Kansas 
City, Missouri 64106, or delivered in duplicate to the Regional Counsel 
at the above address. Comments must be marked: CE197. 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: 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.

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: ``Comments to CE197.'' The postcard will be date 
stamped and returned to the commenter.

Background

    On March 8, 2003, AMSAFE, Inc. Inflatable Restraints Division, 1043 
North 47th Avenue, Phoenix, AZ 85043, applied for a supplemental type 
certificate to install an inflatable lapbelt restraint with a standard 
upper torso restraint (or shoulder harness) in the Zenair model CH2000. 
The model CH2000 is a single engine, two-place airplane with a stall 
speed in the landing configuration that is below 45 knots.
    The inflatable restraint system is a three-point restraint system 
consisting of a shoulder harness and an inflatable airbag lap belt, and 
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 the airplane's yoke and 
instrument panel. 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 airbags are integrated into 
the lapbelt. The shoulder harness is conventional and does not inflate. 
While airbags and inflatable restraints are standard in the automotive 
industry, the use of an inflatable three-point restraint 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 model 
CH2000 occupant restraint design. The FAA has considered the 
installation of airbags as having two primary safety concerns:
    [sbull] That they perform properly under foreseeable operating 
conditions; and
    [sbull] That they do not perform in a manner or at such times as 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 and 
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 yoke. 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 airbag is integrated into the lap belt and 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

[[Page 42316]]

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 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 of the restraint must be 
understood. Therefore, qualification testing of the firing hardware/
software must consider the following:
    [sbull] The airplane vibration levels appropriate for a general 
aviation airplane; 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) 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 Zenair model CH2000 lap 
belt and shoulder harness restraint, the inflatable restraint 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 shoulder harness. 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 
for each occupant under the crash conditions specified in Sec.  23.562 
where it is necessary to prevent serious head injury. The crash pulse 
specified in Sec.  23.562 is viewed as a suitable threshold for system 
deployment. 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 items inside the cockpit while the aircraft is on the 
ground and includes protection against inadvertent deployment.
    In addition, the use and 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. As an alternative, 
AMSAFE, Inc. may show that such deployment is not hazardous to the 
occupant, and will still provide the required protection.
    The cockpit of the model CH2000 is a confined area, 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 area.
    Fire is a concern for any airplane, regardless of the size or class 
of the airplane. 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 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 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 Zenair model CH2000, as changed, continues to meet the applicable 
provisions of the regulations incorporated by reference in Type 
Certificate No. TA5CH 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. TA5CH are as follows:

    FAR 21.29 and FAR 23 effective February 1, 1965, as amended by 
23-1 through 23-42. JAR-VLA effective April 26, 1990, through 
Amendment VLA/92/1 effective January 1, 1992, used as a safety 
equivalence to FAR 23, as provided by AC 23-11. FAR 36 dated 
December 1, 1969, as amended by current amendment as of date of type 
certification.

For the 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 AMSAFE, Inc. inflatable restraint 
as installed on Zenair model CH2000 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 Zenair model CH2000 will incorporate the following novel or 
unusual design feature:
    The AMSAFE, Inc. Inflatable Three-Point Self-Adjusting Restraint 
safety belt with an integrated inflatable airbag device. The purpose of 
the inflatable airbag seatbelt is to reduce the potential for injury in 
the event of an accident. In a severe impact, an airbag will deploy 
from the lapbelt portion of the restraint,

[[Page 42317]]

in a manner similar to an automotive airbag. The airbag will deploy 
between the head of the occupant and the airplane's yoke and instrument 
panel. 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 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. 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 Zenair 
model CH2000 equipped with the AMSAFE, Inc. Three-Point Self-Adjusting 
Restraint safety belt with an integrated inflatable airbag device. 
Other conditions may be developed, as needed, based on further FAA 
review and discussions with the manufacturer and civil aviation 
authorities.

Applicability

    As discussed above, these special conditions are applicable to the 
Zenair model CH2000 equipped with the AMSAFE, Inc. Three-Point Self-
Adjusting Restraint safety belt with an integrated inflatable airbag 
device. Should AMSAFE, Inc. apply at a later date for a supplemental 
type certificate to modify any other model on Type Certificate number 
TA5CH 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.

Conclusion

    This action affects only certain novel or unusual design features 
on the Zenair model CH2000. 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 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 Zenair 
model CH2000 occupant restraint design. Accordingly, the FAA proposes 
the following special conditions as part of the type certification 
basis for the Zenair model CH2000, as modified by AMSAFE, Inc.
Three-Point Self-Adjusting Restraint Safety Belt with an Integrated 
Airbag Device
    1. It must be shown that the inflatable lapbelt will deploy and 
provide protection under the crash conditions specified in Sec.  23.562 
where it is necessary to prevent serious head injuries. The means of 
protection must take into consideration a range of stature from a 5th 
percentile female to a 95th percentile male. The inflatable lapbelt 
must provide a consistent approach to energy absorption throughout that 
range.
    2. The inflatable lapbelt must provide adequate protection for each 
occupant. In addition, unoccupied seats that have active seat belts 
must not constitute a hazard to any occupant.
    3. The design must prevent the inflatable safety belt 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 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) 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 certificated belt and 
shoulder harness.
    6. It must be shown that deployment of the restraint system is not 
hazardous to the occupant or result in injuries that could impede rapid 
egress. This assessment should include occupants whose belt 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 safety belt 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 safety belt 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 safety belt will not 
release hazardous quantities of gas or particulate matter into the 
cabin.
    11. The inflatable safety belt 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 
safety belt 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 June 27, 2003.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 03-18071 Filed 7-16-03; 8:45 am]
BILLING CODE 4910-13-P