[Federal Register Volume 70, Number 126 (Friday, July 1, 2005)]
[Rules and Regulations]
[Pages 37994-37997]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-13093]


=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 23

[Docket No. CE223, Special Conditions No. 23-163-SC]


Special Conditions: AMSAFE, Incorporated; Cirrus Design 
Corporation SR20 and SR22; Inflatable Four-Point Restraint Safety Belt 
with an Integrated Airbag Device

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions; request for comments.

-----------------------------------------------------------------------

SUMMARY: These special conditions are issued for the installation of an 
AMSAFE, Inc., Inflatable Four-Point Restraint Safety Belt with an 
Integrated Airbag Device on Cirrus Models SR20 and SR22. These 
airplanes, as modified by the installation of this Inflatable Safety 
Belt, will have novel and unusual design features associated with the 
upper-torso restraint portions of the four-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 that the Administrator considers necessary to 
establish a level of safety equivalent to that established by the 
existing airworthiness standards.

DATES: The effective date of these special conditions is June 23, 2005. 
Comments must be received on or before August 1, 2005.

ADDRESSES: Comments on these special conditions may be mailed in 
duplicate to: Federal Aviation Administration (FAA), Regional Counsel, 
ACE-7, Attention: Rules Docket, Docket No. CE223, 901 Locust, Room 506, 
Kansas City, Missouri 64106, or delivered in duplicate to the Regional 
Counsel at the above address. Comments must be marked: CE223. 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. Mark James, Federal Aviation 
Administration, Aircraft Certification Service, Small Airplane 
Directorate, ACE-111, 901 Locust, Kansas City, Missouri, 816-329-4137, 
fax 816-329-4090, e-mail [email protected].

SUPPLEMENTARY INFORMATION: The FAA has determined that notice and 
opportunity for prior public comment is impractical because these 
procedures would significantly delay issuance of approval and thus 
delivery of the affected aircraft. In addition, the substance of these 
special conditions has been subject to the public comment process in 
several prior instances with no substantive comments received. The FAA, 
therefore, finds that good cause exists for making these special 
conditions effective upon issuance.

Comments Invited

    Interested persons are invited to submit such written data, views 
or arguments, as they may desire. Communications should identify the 
regulatory docket or special condition 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 special conditions 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. Commenters wishing the FAA to acknowledge receipt of their 
comments submitted in response to this notice must include a self-
addressed, stamped postcard on which the following statement is made: 
``Comments to CE223.'' The postcard will be date stamped and returned 
to the commenter.

Background

    On September 24, 2004, Cirrus Design Corporation requested a Type 
Design Project, for the installation of an AMSAFE four-point safety 
belt restraint system incorporating an inflatable airbag for the pilot 
and co-pilot seats of the Cirrus Design Corporation model SR20 and SR22 
airplanes. The Cirrus models SR20 and SR22 are single engine, four-
place airplanes.
    The inflatable restraint system is four-point safety belt restraint 
system consisting of a lap belt 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. 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 four-
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 Cirrus 
Design Corporation Models SR20 and SR22 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 as 
to impede the pilot's ability to maintain control of

[[Page 37995]]

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 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 these 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. Cirrus Design Corporation 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, 
general aviation aircraft are susceptible to 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 Cirrus Design Corporation 
SR20 and SR22 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 approved belt and 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. The seats of the models SR20 
and SR22 are certificated to the structural requirements of Sec.  
23.562. Therefore, the test crash pulses identified in Sec.  23.562 
must be used to satisfy this requirement.
    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. The 
restraint must also provide suitable visual warnings that would alert 
rescue personnel to the presence of an inflatable restraint system.
    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, Cirrus Design Corporation may 
show that such deployment is not hazardous to the occupant and will 
still provide the required protection.
    The cabins of the Cirrus model airplanes identified in these 
special conditions are confined areas, and the FAA is concerned that 
noxious gasses may accumulate in the event of airbag 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, Cirrus Design Corporation, 
must show that the Cirrus models SR20 and SR22, as changed, continue to 
meet the applicable provisions of the regulations incorporated by 
reference in Type Certificate No. A00009CH 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 are as follows:
    Cirrus SR20: Part 23 of the Federal Aviation Regulations dated 
February 1, 1965, as amended by 23-1 through 23-47 except as follows: 
FAR 23.573, 23.575, 23.611, 23.657, 23.673 through Amendment 23-48. FAR 
23.783, 23.785, 23.867, 23.1303, 23.1307, 23.1309, 23.1311, 23.1321, 
23.1323, 23.1329, 23.1361, 23.1383, 23.1401, 23.1431, 23.1435 through 
Amendment 23-49. FAR 23.3, 23.25, 23.143, 23.145, 23.155, 23.1325, 
23.1521, 23.1543, 23.1555, 23.1559, 23.1567, 23.1583, 23.1585, 23.1589 
through Amendment 23-50. FAR 23.777, 23.779, 23.901, 23.907, 23.955, 
23.959, 23.963, 23.965, 23.973, 23.975, 23.1041, 23.1091, 23.1093,

[[Page 37996]]

23.1107, 23.1121, 23.1141, 23.1143, 23.1181, 23.1191, 23.1337 through 
Amendment 23-51. FAR 23.1305 through Amendment 23-52. FAR 36 dated 
December 1, 1969, as amended by current amendment as of the date of 
Type Certification.
    Cirrus SR22: Part 23 of the Federal Aviation Regulations dated 
February 1, 1965, as amended by 23-1 through 23-53 except as follows: 
FAR 23.301 through Amendment 47. FAR 23.855, 23.1326, 23.1359, not 
applicable. FAR 36 dated December 1, 1969, as amended by current 
amendment as of the date of Type Certification.
    For all the models listed above, the certification basis also 
includes all exemptions, if any; equivalent level of safety findings, 
if any; and special conditions not relevant to 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 Cirrus Design Corporation 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 Cirrus Design Corporation models SR20 and SR22 will incorporate 
the following novel or unusual design feature:
    The AMSAFE, Inc., Four-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 airplane 
interior structure. Therefore, this will 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 Cirrus 
Design Corporation models equipped with the AMSAFE, Inc., 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.

Applicability

    As discussed above, these special conditions are applicable to the 
Cirrus Design Corporation models SR20 and SR22 equipped with the 
AMSAFE, Inc., four-point inflatable restraint system. Should Cirrus 
Design Corporation, at a later date, request to modify any other model 
on the Type Certificate identified in these special conditions 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 previously identified Cirrus models. 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.
    Under standard practice, the effective date of final special 
conditions would be 30 days after the date of publication in the 
Federal Register; however, the substance of these special conditions 
has been subjected to the notice and comment period in several prior 
instances and has been derived without substantive change from those 
previously issued. It is unlikely that prior public comment would 
result in a significant change from the substance contained herein. For 
this reason, and because a delay would significantly affect the 
certification of the airplane, which is imminent, the FAA has 
determined that prior public notice and comment are unnecessary and 
impracticable, and good cause exists for adopting these special 
conditions upon issuance. The FAA is requesting comments to allow 
interested persons to submit views that may not have been submitted in 
response to the prior opportunities for comment described above.

List of Subjects in 14 CFR Part 23

    Aircraft, Aviation safety, Signs and symbols.

Citation

0
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; and 14 CFR 11.38 and 11.19.

The Special Conditions

0
The FAA has determined that this project will be accomplished on the 
basis of not lowering the current level of safety of the Cirrus Design 
Corporation models SR20 and SR22 occupant restraint system. 
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 these models, as modified by AMSAFE, 
Incorporated.
    Inflatable Four-Point Restraint Safety Belt with an Integrated 
Airbag Device on the Pilot and Copilot Seats of the Cirrus Design 
Corporation Models SR20 and SR22.
    1. It must be shown that the inflatable restraint will deploy and 
provide protection under crash conditions. Compliance will be 
demonstrated using the dynamic test condition specified in 14 CFR part 
23, Sec.  23.562(b)(2). It is not necessary to account for floor 
warpage, as required by Sec.  23.562(b)(3). 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.

[[Page 37997]]

    5. It must be extremely improbable for an inadvertent deployment of 
the restraint system to occur, or an inadvertent deployment must 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) four-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. In addition, the 
restraint must also provide suitable visual warnings that would alert 
rescue personnel to the presence of an inflatable restraint system.
    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 before 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 23, 2005.
John R. Colomy,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 05-13093 Filed 6-30-05; 8:45 am]
BILLING CODE 4910-13-P