[Federal Register: July 17, 2003 (Volume 68, Number 137)]
[Proposed Rules]
[Page 42315-42317]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr17jy03-20]
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Proposed Rules
Federal Register
________________________________________________________________________
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.
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[[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,
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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