Source: https://www.federalregister.gov/documents/2003/10/14/03-25950/special-conditions-amsafe-incorporated-zenair-model-ch2000-inflatable-three-point-self-adjusting
Timestamp: 2018-04-22 07:33:01
Document Index: 6496309

Matched Legal Cases: ['§\u200923', '§\u200923', '§\u200923', '§\u200923', 'arts 21', 'art 21', 'art 23', '§\u200923', '§\u200923', '§\u200923', '§\u200923', '§\u200923', '§\u200923', '§\u200923', '§\u200923', '§\u200923', '§\u200923', '§\u200923']

59095-59097 (3 pages)
Special Conditions No. 23-138-SC
https://www.federalregister.gov/d/03-25950 https://www.federalregister.gov/d/03-25950
Start Preamble Start Printed Page 59095
These special conditions are issued 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 with the lap belt portion of the 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.
On March 8, 2003, AMSAFE, Inc. Inflatable Restraints Division, 5456 East McDowell Road, Mesa, AZ, 85215, 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 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 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.
The inflatable seatbelt system must deploy and provide protection for each occupant under a crash condition where it is necessary to prevent serious head injury. However, the Zenair CH2000 seats are not certificated to the requirements specified in § 23.562 and it is not known if they would remain intact following exposure to the crash pulse identified in § 23.562. Therefore, the test crash pulse used to satisfy this requirement may have a peak longitudinal deceleration lower than that required by § 23.562. However, the test pulse must have an onset rate (deceleration divided by time) equal to or greater than the onset rate of the Start Printed Page 59096pulse described in § 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 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's 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.
The cockpit of the model CH2000 is a confined area, and the FAA is concerned that noxious gasses may accumulate in the event the inflatable restraint 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 area.
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.
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, 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.
Title 14 of the Code of Federal Regulations, parts 21 and 23, 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.
Notice of proposed special conditions No. 23-03-01-SC for the Zenair model CH2000 equipped with the AMSAFE, Inc. Three-Point Self-Adjusting Restraint safety belt with an integrated airbag device was published on July 17, 2003 (68 FR 42315). One comment was received, regarding the requirement that the lapbelt must deploy and provide protection under the crash conditions specified in § 23.562 (proposed Special Condition No. 1).
The commenter is in general agreement with the special conditions proposed for this particular program. In addition, the commenter is in agreement that a dynamic test is necessary to demonstrate the deployment timing and positioning of the inflatable lapbelt. However, the commenter states that proposed SC No. 1, as written, requires the inflatable restraint to operate only when subjected to the crash pulse Start Printed Page 59097identified in § 23.562. In addition, since the seats installed in the Zenair CH2000 do not meet the requirements of § 23.562, an inflatable restraint that operates only after being exposed to this pulse may offer little benefit.
The commenter suggests that reference to § 23.562 be retained, but allow for the following:
The test pulse may have a reduction in the peak longitudinal deceleration but the onset rate (deceleration divided by time) must be equal to or greater than the pulse specified in § 23.562.
The peak longitudinal deceleration must be greater than the deployment threshold of the crash sensor.
The peak longitudinal deceleration must be equal to or greater than the forward static design load factors required by the original certification basis of the airplane.
The FAA concurs. The seats installed in the Zenair CH2000 may not satisfy the requirements of § 23.562, so it is not appropriate to install an inflatable restraint that will deploy only when subjected to the crash pulse specified in § 23.562. The FAA agrees that the test pulse used to satisfy the dynamic test requirements must be less severe than that specified in § 23.562. In addition, we agree with the commenter that the onset rate of the test pulse should be equal to or greater than the onset rate of the pulse required by § 23.562. This will show that the crash sensor will trigger when exposed to a high deceleration that builds up in rapid time, like a real crash event.
The FAA will incorporate the commenter's input into Special Condition No. 1.
Accordingly, pursuant to the authority delegated to me by the Administrator, the following special conditions are issued as part of the typ certification basis for the Zenair model CH2000, as modified by AMSAFE, Inc.
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 dynamic test condition specified in § 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 then the crash pulse identified in § 23.562.
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.
[FR Doc. 03-25950 Filed 10-10-03; 8:45 am]