Source: https://www.federalregister.gov/documents/2002/08/30/02-22118/special-conditions-bombardier-model-cl-600-2c10-series-airplanes-seats-with-inflatable-lapbelts
Timestamp: 2017-08-19 15:38:02
Document Index: 553226178

Matched Legal Cases: ['art 25', '§\u200925', '§\u200921', '§\u200921', 'art 25', '§\u200925', '§\u200925', '§\u200921', 'art 25', '§\u200921', 'art 34', 'art 36', 'art 25', '§\u200925', '§\u200921']

Federal Register :: Special Conditions: Bombardier Model CL-600-2C10 Series Airplanes; Seats With Inflatable Lapbelts
Special Conditions: Bombardier Model CL-600-2C10 Series Airplanes; Seats With Inflatable Lapbelts
67 FR 55706
55706-55710 (5 pages)
Docket No. NM220
Special Conditions No. 25-210-SC
02-22118
SUPPLEMENTARY INFORMATION:Start Printed Page 55707
https://www.federalregister.gov/d/02-22118 https://www.federalregister.gov/d/02-22118
These special conditions are issued for the Bombardier Model CL-600-2C10 series airplane. This airplane as modified by Weber Aircraft will have a novel or unusual design feature associated with inflatable lapbelts. 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.
Comments on these special conditions may be mailed in duplicate to: Federal Aviation Administration, Transport Airplane Directorate, Attn: Rules Docket (ANM-113), Docket No. NM220, 1601 Lind Avenue SW., Renton, Washington, 98055-4056; or delivered in duplicate to the Transport Airplane Directorate at the above address. Comments must be marked: Docket No. NM220 Comments may be inspected in the Rules Docket weekdays, except Federal holidays, between 7:30 a.m. and 4 p.m.
Mike Thompson, FAA, Airframe and Cabin Safety Branch, ANM-115, Transport Airplane Directorate, Aircraft Certification Service, 1601 Lind Avenue SW., Renton, Washington 98055-4056; telephone (425) 227-1157; facsimile (425) 227-1149.
Although this action is in the form of final special conditions and, for the reasons stated above, is not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to submit written comments, data, or views. The most helpful comments reference a specific portion of the special conditions, explain the reason for any recommended change, and include supporting data. We ask that you send us two copies of written comments.
In a letter dated January 29, 2002, Weber Aircraft applied for a supplemental type certificate to install AMSAFE Aviation Inflatable Restraints (AAIR) inflatable lapbelts for head injury protection on certain seats in Bombardier Model CL-600-2C10 series airplanes. The Bombardier Model CL-600-2C10 series airplane is a swept-wing, conventional-tail, twin-engine, turbofan-powered transport airplane currently approved under Type Certificate No. A21EA. The inflatable lapbelt is designed to limit occupant forward movement in the event of an accident. This will reduce the potential for head injury, thereby reducing the head injury criteria (HIC) calculation. The inflatable lapbelt behaves similarly to an automotive inflatable airbag, but in this case the airbag is integrated into the lapbelt, and inflates away from the seated occupant. While inflatable airbags are now standard in the automotive industry, the use of an inflatable lapbelt is novel for commercial aviation.
Title 14 Code of Federal Regulations (14 CFR) 25.785 requires that occupants be protected from head injury by either the elimination of any injurious object within the striking radius of the head, or by padding. Traditionally, this has required a setback of 35 inches from any bulkhead or other rigid interior feature or, where that is not practical, specified types of padding. The relative effectiveness of these means of injury protection had not been quantified. With the adoption of Amendment 25-64 to 14 CFR part 25, specifically § 25.562, a new standard that quantifies required head injury protection was created.
Section 25.562 specifies that dynamic tests must be conducted for each seat type installed in the airplane. In particular, the regulations require that persons not suffer serious head injury under the conditions specified in the tests, and that a HIC measurement of not more than 1000 units be recorded, should contact with the cabin interior occur. While the test conditions described in this section of the regulations are specific, it is the intent of the requirement that an adequate level of head injury protection be provided for crash severity up to and including that specified.
Amendment 25-64 is part of the Bombardier Model CL-600-2C10 series airplane certification basis. Therefore, the seat installation with inflatable lapbelts must meet the requirement that a HIC measurement of less than 1000 be demonstrated for occupants of seats incorporating the inflatable lapbelt.
The inflatable lapbelt will rely on electronic sensors for signaling to activate pyrotechnic charges, which then activate the lapbelt when needed. These same devices could be susceptible to inadvertent activation, causing deployment in a potentially unsafe manner. The consequences of such deployment must be considered in establishing the reliability of the system. AMSAFE must substantiate that the effects of an inadvertent deployment in flight are either not a hazard to the airplane, or that such deployment is an extremely improbable occurrence (less than 10−9 per flight hour). The effect of an inadvertent deployment on a passenger or crewmember that might be positioned close to the inflatable lapbelt should also be considered. The person could be either standing or sitting. A minimum reliability level will have to be established for this case, depending upon the consequences, even if the effect on the airplane is negligible.
The potential for an inadvertent deployment could be increased as a result of conditions in service. The installation must take “wear and tear” into account so that the likelihood of an inadvertent deployment is not increased Start Printed Page 55708to an unacceptable level. In this context, an appropriate inspection interval and self-test capability are considered necessary. Other outside influences are lightning and high intensity electromagnetic fields (HIRF). Since the sensors that trigger deployment are electronic, they must be protected from the effects of these threats. Existing Special Conditions No. 25-ANM-109 regarding lightning and HIRF are therefore applicable. For the purposes of compliance with those special conditions, if inadvertent deployment could cause a hazard to the airplane, the inflatable lapbelt is considered a critical system. If inadvertent deployment could cause injuries to persons, the inflatable lapbelt should be considered an essential system. Finally, the inflatable lapbelt installation should be protected from the effects of fire, so that an additional hazard is not created by, for example, a rupture of the pyrotechnic squib.
In order to be an effective safety system, the inflatable lapbelt must function properly and must not introduce any additional hazards to occupants as a result of its functioning. There are several areas in which the inflatable lapbelt differs from traditional occupant protection systems, and requires special conditions to ensure adequate performance.
Because the inflatable lapbelt is essentially a single use device, there is the potential that it could deploy under crash conditions that are not sufficiently severe to require head injury protection from the inflatable lapbelt. Since an actual crash is frequently composed of a series of impacts before the airplane comes to rest, this could render the inflatable lapbelt useless if a larger impact follows the initial impact. This situation does not exist with energy absorbing pads or upper torso restraints, which tend to provide protection according to the severity of the impact. Therefore, the inflatable lapbelt installation should be such that the inflatable lapbelt will provide protection when it is required, and will not expend its protection when it is not needed. These special conditions contain no requirement for the inflatable lapbelt to provide protection from multiple impacts, where more than one impact would require protection.
Since the inflatable lapbelt will be electrically powered, there is the possibility that the system could fail due to a separation in the fuselage. Since this system is intended as a crash/post-crash protection means, failure due to fuselage separation is not acceptable. As with emergency lighting, the system should function properly if such a separation occurs at any point in the fuselage. A separation that occurs at the location of the inflatable lapbelt would not have to be considered.
Since the inflatable lapbelt is likely to have a large volume displacement, the inflated bag could potentially impede egress of passengers. The bag deflates to absorb energy, so it is likely that an inflatable lapbelt would be deflated at the time that persons would be trying to leave their seats. Nonetheless, it is considered appropriate to specify a time interval after which the inflatable lapbelt may not impede rapid egress. Ten seconds has been chosen as a reasonable time, since this corresponds to the maximum time allowed for an exit to be openable. In actuality, it is unlikely that an exit would be prepared this quickly in an accident severe enough to warrant deployment of the inflatable lapbelt, and the inflatable lapbelt will likely deflate in much less than ten seconds.
Under the provisions of § 21.101 Amendment 21-69, effective September 16, 1991, Weber Aircraft must show that the Bombardier Model CL-600-2C10 series airplane, as changed, continues to meet the applicable provisions of the regulations incorporated by reference in Type Certificate No. A21EA or the applicable regulations in effect on the date of application for the change. Subsequent changes have been made to § 21.101 as part of Amendment 21-77, but those changes do not become effective until June 10, 2003. 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. A21EA are 14 CFR part 25 dated February 1, 1965, including Amendments 25-1 through 25-86, with the following exceptions: Section 25.783(f) as amended by Amendment 25-23 for the cargo compartment door, the main avionics compartment door, and the service/emergency door; § 25.571 as amended by Amendment 25-96, and § 25.493 as amended by Amendment 25-97. The U.S. type certification basis for the Bombardier Model CL-600-2C10 series airplanes is established in accordance with §§ 21.29 and 21.17 and the type certification application date. The U.S. type certification basis is listed in Type Certificate Data Sheet No. A21AE.
If the Administrator finds that the applicable airworthiness regulations (i.e., 14 CFR part 25) do not contain adequate or appropriate safety standards for the Bombardier Model CL-600-2C10 series airplane because of a novel or unusual design feature, special conditions are prescribed under the provisions of § 21.16.
In addition to the applicable airworthiness regulations and special conditions, the Bombardier Model CL-600-2C10 series airplane must comply with the fuel vent and exhaust emission requirements of 14 CFR part 34 and the Start Printed Page 55709noise certification requirements of 14 CFR part 36.
Weber Aircraft is proposing to install an inflatable lapbelt on certain seats of Bombardier CL-600-2C10 series airplanes, in order to reduce the potential for head injury in the event of an accident. The inflatable lapbelt works similarly to an automotive airbag, except that the airbag is integrated with the lap belt of the restraint system. The inflatable lapbelts are considered a novel or unusual design feature.
Federal regulations state the performance criteria for head injury protection in objective terms. However, none of these criteria are adequate to address the specific issues raised concerning seats with inflatable lapbelts. The FAA has therefore determined that, in addition to the requirements of part 25, special conditions are needed to address requirements particular to installation of seats with inflatable lapbelts.
Accordingly, in addition to the passenger injury criteria specified in § 25.785, these special conditions are adopted for the Bombardier Model CL-600-2C10 series airplanes equipped with inflatable lapbelts. Other special conditions may be developed, as needed, based on further FAA review and discussions with the manufacturer and civil aviation authorities.
From the standpoint of a passenger safety system, the inflatable lapbelt is unique in that it is both an active and entirely autonomous device. While the automotive industry has good experience with airbags, the conditions of use and reliance on the inflatable lapbelt as the sole means of injury protection are quite different. In automobile installations, the airbag is a supplemental system and works in conjunction with an upper torso restraint. In addition, the crash event is more definable and of a typically shorter duration, which can simplify the activation logic. The airplane operating environment is also quite different from that of automobiles and includes the potential for greater “wear and tear,” and unanticipated abuse conditions (due to galley loading, passenger baggage, etc.). Airplanes also operate where exposure to high intensity electromagnetic fields could affect the activation system.
The following special conditions can be characterized as addressing either the safety performance of the system or the system's integrity against inadvertent activation. Because a crash requiring use of the inflatable lapbelts is a relatively rare event, and because the consequences of an inadvertent activation are potentially quite severe, these latter requirements are probably the more rigorous from a design standpoint.
One comment was received in response to the most recent publication of inflatable lapbelt special conditions (65 FR 60343), which are substantially identical to the special conditions contained herein. The disposition of this comment is contained in Rules Docket No. NM176 and is available for examination by interested parties. In our disposition, we agreed with the commenter, but noted that the substance of the comment has already been addressed in showing compliance with existing regulations during the certification process. Therefore, this comment did not result in a change to the special conditions.
As discussed above, these special conditions are applicable to the Bombardier Model CL-600-2C10 series airplane. Should Weber Aircraft apply at a later date for a supplemental type certificate to modify any other model included on Type Certificate No. A21EA to incorporate the same novel or unusual design feature, the special conditions would apply to that model as well under the provisions of § 21.101(a)(1) Amendment 21-69, effective September 16, 1991.
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 Bombardier Model CL-600-2C10 series airplanes modified by Weber Aircraft.
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 injury. The means of protection must take into consideration a range of stature from a two-year-old child to a ninety-fifth percentile male. The inflatable lapbelt must provide a consistent approach to energy absorption throughout that range. In addition, the following situations must be considered:
3. The design must prevent the inflatable lapbelt from being either incorrectly buckled or incorrectly installed so that the inflatable lapbelt would not properly deploy. Alternatively, it must be shown that such deployment is not hazardous to the occupant, and will provide the required head injury protection. Start Printed Page 55710
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) likely to be experienced in service.
9. The system must be protected from lightning and HIRF. The threats specified in Special Condition No. 25-ANM-109 are incorporated by reference for the purpose of measuring lightning and HIRF protection. For the purposes of complying with HIRF requirements, the inflatable lapbelt system is considered a “critical system” if its deployment could have a hazardous effect on the airplane; otherwise it is considered an “essential” system.
[FR Doc. 02-22118 Filed 8-29-02; 8:45 am]