[Federal Register: September 14, 2004 (Volume 69, Number 177)]
[Proposed Rules]
[Page 55367-55369]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr14se04-16]
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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.
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[[Page 55367]]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 23
[Docket No. CE210; Notice No. 23-04-01-SC]
Special Conditions: AMSAFE, Incorporated, Sky International A1,
A1A, A1B, Inflatable Five-Point Seatbelt Airbag Restraint
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 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. The proposed 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: Comments must be received on or before October 14, 2004.
ADDRESSES: Comments on this proposal may be mailed in duplicate to:
Federal Aviation Administration (FAA), Regional Counsel, ACE-7,
Attention: Rules Docket, Docket No. CE210, 901 Locust, Room 506, Kansas
City, Missouri 64106, or delivered in duplicate to the Regional Counsel
at the above address. Comments must be marked: CE210. 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-114, 901 Locust, Kansas City, Missouri, 816-329-4128,
fax 816-329-4090, e-mail: pat.mullen@faa.gov.
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 CE210''. The postcard will be date
stamped and returned to the commenter.
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:
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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 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.
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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.
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 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.
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 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 Sky
International models A1, A1A, and A1B occupant restraint system.
Accordingly, the FAA proposes the following special conditions as part
of the type certification basis for these models, 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 August 26, 2004.
David R. Showers,
Acting Manager, Small Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 04-20622 Filed 9-13-04; 8:45 am]
BILLING CODE 4910-13-P