Special Conditions: AmSafe Aviation; Inflatable Restraints Installation; Approved Model List of Normal and Utility Category Airplanes, and Agricultural Airplanes Certificated in the Normal/Utility/Restricted Category

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Final special conditions; request for comments.

SUMMARY:

These special conditions are issued for AmSafe Aviation for a list of approved models. These airplanes, as modified by AmSafe Aviation, will have novel and unusual design features associated with the lap belt or shoulder harness portion of the safety belt, which contains an integrated airbag device. The applicable airworthiness regulations do not contain adequate and 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 airworthiness standards.

DATES:

The effective date of these special conditions is December 26, 2007. Comments must be received on or before February 1, 2008.

ADDRESSES:

Mail two copies of your comments on these special conditions to: Federal Aviation Administration (FAA), Regional Counsel, ACE-7, Attention: Rules Docket, Docket No. CE285, 901 Locust, Room 506, Kansas City, Missouri 64106, or you may deliver two copies to the Regional Counsel at the above address. Mark your comments: Docket No. CE285. You may inspect comments in the Rules Docket weekdays, except Federal holidays, between 7:30 a.m. and 4 p.m.

FOR FURTHER INFORMATION CONTACT:

Mr. Bob Stegeman, Federal Aviation Administration, Small Airplane Directorate, Aircraft Certification Service, ACE-111, 901 Locust, Kansas City, Missouri, 816-329-4140, fax 816-329-4090, e-mail Robert.Stegeman@faa.gov.

SUPPLEMENTARY INFORMATION:

The FAA has determined that notice and opportunity for prior public comment hereon are impracticable because these procedures would significantly delay issuance of the approval design 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

We invite interested persons to participate in the making of these proposed special conditions by submitting such written data, views, or arguments as they may desire. Identify the regulatory docket or notice number and submit the comments in duplicate to the address specified above. The most helpful comments reference a specific portion of the special conditions, explain the reason for any recommended change, and include supporting data. 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 CE285.” The postcard will be date stamped and returned to the commenter.

Background

On March 8, 2007, AmSafe Aviation, 1043 North 47th Avenue, Phoenix, AZ 85043, applied for a supplemental type certificate for the installation of inflatable restraints in additional airplane models included herein that were certificated prior to the dynamic seat rule specified in 14 CFR part 23, § 23.562 and in agricultural airplanes.

AmSafe Aviation has previously applied for and obtained an Approved Model List (AML) Supplemental Type Certificate (STC) for the installation of Inflatable Two-, Three-, Four- or Five-Point Restraint Safety Belts with an Integrated Airbag Device in airplanes certificated in the Part 23 Normal/Utility categories.

The current AML STC does not allow airbags in agricultural aircraft. However, AmSafe recently provided the FAA data showing the installation of inflatable restraints in agricultural airplanes would have a positive safety effect. This special condition amends the existing AML STC to include additional normal category aircraft and to allow airbag installation in agricultural aircraft.

The inflatable restraint system is either a two-, three-, four-, or five-point safety belt restraint system consisting of a shoulder harness and a lap belt with an inflatable airbag attached to either the lap belt or the shoulder harness. The inflatable portion of the restraint system will rely on sensors to electronically activate the inflator for deployment. The inflatable restraint system will be made available on the pilot, co-pilot, and passenger seats of these airplanes.

If an emergency landing occurs, 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. However, in this case, the airbag is integrated into the lap or shoulder belt. While airbags and inflatable restraints are standard in the automotive industry, the use of an inflatable restraint system is novel for aircraft operations.

The FAA has determined that this project will be accomplished on the basis of not lowering the current level of safety of the airplanes' original certification basis. 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 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 it may 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. This consideration is of special concern for aircraft designated for agricultural use because these aircraft spend a majority of their flight time at low altitudes. 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. AmSafe Aviation 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. Recent analysis provided to the FAA in a July 2006 AmSafe Aviation report based upon National Agricultural Aviation Association accident data shows that the risk of inadvertent deployment is outweighed by the potential safety improvement added by the enhanced restraint system. Given this data, the FAA believes that the improved restraint system will result in an increased margin of safety in comparison with existing designs.

In addition, general aviation and agricultural 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 general aviation and agricultural airplanes; and
• The inertial loads that result from typical flight/ground maneuvers, gusts, hard landings and flight maneuvering unique to both general aviation and agricultural aircraft operations.

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 Aviation 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 retrofitted airplane occupant restraints, the inflatable restraint system must show that it will offer an equivalent level of protection in the event of an emergency landing. If a deployment occurs, 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 during crash conditions as specified in the original certification basis. Therefore, the test emergency landing loads identified in the original certification basis of the airplane must be used to satisfy this requirement. It must be shown that the inflatable restraint will deploy and provide protection under crash conditions as specified in the original certification basis. Compliance will be demonstrated using the test condition specified in the original certification basis. It must be shown that the crash sensor will trigger when exposed to a rapidly applied deceleration, like an actual crash event. Therefore, the test crash pulses identified in § 23.562 must be used to satisfy this requirement, although, the peak “G” may be reduced to a level meeting the original certification requirements of the aircraft. Testing to these pulses 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.

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 Aviation can establish inspection intervals where they have demonstrated the system to be reliable between these intervals.

An inflatable restraint may 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, AmSafe Aviation may show that such deployment is not hazardous to the occupant and will still provide the required protection.

The cabins of the various model airplanes identified in these special conditions are confined areas, and the FAA is concerned that noxious gasses may accumulate if an airbag deploys. 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 it may 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.

Special conditions for the installation of AAIR systems on other certificated airplanes have been issued and no substantive public comments were received. Since the same special conditions were issued multiple times for different model airplanes with no substantive public comments, the FAA began issuing direct final special conditions with an invitation for public comment. This was done to eliminate the waiting period for public comments and to allow AmSafe Aviation to proceed with the project.

These previous special conditions were typically issued for a single model airplane or for variants of a model from a single airplane manufacturer, and required dynamic testing of each AAIR system installation for showing compliance. Additionally, a previous AML STC was issued for AmSafe Aviation including numerous airplane models and manufacturers. Since AmSafe Aviation has previously demonstrated by dynamic testing, and has the supporting data, that the Electronics Module Assembly (EMA) and inflator assembly will function as intended in a simulated dynamic emergency landing, it is not necessary to repeat the test for each airplane model shown in these special conditions.

Type Certification Basis

Under the provisions of 14 CFR part 21, § 21.101, AmSafe Aviation must show that affected airplane models, as changed, continue to meet the applicable provisions of the regulations incorporated by reference in the Type Certificate Numbers listed below 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” and can be found in the Type Certificate Numbers listed below. The following models are covered by this special condition:[?USGPO Galley End:?]

The following aircraft are certified in the restricted category:

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 Aviation, inflatable restraint as installed on these models because of a novel or unusual design feature. Therefore, special conditions are prescribed under the provisions of § 21.16.

Special conditions, as appropriate, as defined in § 11.19, are issued in accordance with § 11.38, and become part of the type certification basis in accordance with § 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 § 21.101.

Novel or Unusual Design Features

The various airplane models will incorporate the following novel or unusual design feature:

The AmSafe Aviation Inflatable Two-, Three-, Four-, or Five-Point Restraint Safety Belt with an Integrated Airbag Device.

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 the restraint, in a manner similar to an automotive airbag. The airbag will deploy between the head of the occupant and airplane interior 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. 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 various airplane models equipped with the AmSafe Aviation, two-, three-, four-, or 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 Approved Model List (AML) above. Should AmSafe Aviation apply at a later date for a supplemental type certificate to modify any other model included on the type certificates listed above to incorporate the same novel or unusual design feature, the special conditions would apply to that model as well.

Conclusion

This action affects only certain novel or unusual design features on the previously identified airplane 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, as the certification date for these airplane models, as modified by AmSafe Aviation, is imminent, the FAA finds that good cause exists to make these special conditions effective upon issuance.

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; and 14 CFR 11.38 and 11.19.

The Special Conditions

The FAA has determined that this project will be accomplished on the basis of not lowering the current level of safety of the occupant restraint system for the airplane models listed in these special conditions. Accordingly, the FAA is issuing the following special conditions as part of the type certification basis for these models, as modified by AmSafe, Aviation.

Inflatable Two-, Three-, Four-, or Five-Point Restraint Safety Belt with an Integrated Airbag Device Installed in an Airplane Model

1a. It must be shown that the inflatable restraint will provide restraint protection under the emergency landing conditions specified in the original certification basis of the airplane. Compliance will be demonstrated using the static test conditions specified in the original certification basis for each airplane.

1b. It must be shown that the crash sensor will trigger when exposed to a rapidly applied deceleration, like an actual emergency landing event. Therefore, compliance may be demonstrated using the deceleration pulse specified in para. 23.562, which may be modified as follows:

I. The peak longitudinal deceleration may be reduced; however, the onset rate of the deceleration must be equal to or greater than the emergency landing pulse identified in para. 23.562.

II. The peak longitudinal deceleration must be above the deployment threshold of the sensor, and equal or greater than the forward static design longitudinal load factor required by the original certification basis of the airplane.

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 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 (C22g or C114) restraint.

6. It must be shown that deployment of the inflatable restraint system is not hazardous to the occupant or will not result in injuries that could impede rapid egress. This assessment should include occupants whose restraints are loosely fastened.

7. It must be shown that an inadvertent deployment that could cause injury to a 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.