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Proposed Technical Standard Order-TSO-C39c, Aircraft Seats and Berths

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Federal Aviation Administration, DOT.


Notice of availability and requests for public comments.


This notice announces the availability of and request comments on a proposed Technical Standard Order (TSO) C39c, Aircraft Seats and Berths. The proposed TSO-C39c, Aircraft Seats and Berths, prescribes the minimum performance standard (MPS) that a aircraft seat and berth must meet in order to bear the TSO number on its identification plate. Proposed TSO-C39c provides standards for seating systems in transport, rotorcraft, normal and utility airplanes, and acrobatic.


Comments must be received on or before September 15, 2002.


Send all comments on the proposed technical standard order to: Federal Aviation Administration, Aircraft Certification Service, Aircraft Engineering Division, Technical Programs and Continued Airworthiness Branch, AIR-120, ATTN: Bobbie J. Smith, Room 815, 800 Independence Avenue, SW., Washington, DC 20591. Or, deliver comments to: Federal Aviation Administration, Room 815, 800 Independence Avenue, SW., Washington, DC 20591.

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Ms. Bobbie J. Smith, AIR-120, Aircraft Certification Service, Aircraft Engineering Division, Federal Aviation Administration, 800 Independence Avenue, SW., Washington, DC 20591, Telephone 202-267-9546.

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Comment Invited

Interested persons are invited to comment on the proposed TSO listed in this notice by submitting such written data, views, or arguments as they desire to the above specified address. Comments received on the proposed TSO may be examined, before and after the comment closing date, in Room 815, FAA Headquarters Building (FOB-10A), 800 Independence Avenue, SW., Washington, DC 20591, weekdays except Federal holidays, between 8:30 a.m. and 4:30 p.m. All communications received on or before the closing date for comments specified above will be considered by the Director of the Aircraft Certification Service before issuing the final TSO.


This TSO is proposed to provide minimum performance standards for aircraft seats and berths.

TSO-C39 was originally developed to provide a standard that would serve as a basis for FAA approval to meet the emergency landing loads specified in the airworthiness requirements. Specifically TSO-C39 replaced TSO-C25 as the seat standards when the certification basis for aircraft changed from including a forward crash load of 6g's to 9g's.

TSO-C39 incorporated NAS 809 to provide the criteria that cold be used to demonstrate the strength of aircraft seats to the 9g-standard. In 1988, a new requirement for seat strength and performance, commonly called the 16g rule, was promulgated in the Federal Aviation Regulation. The 16g rule was fundamentally different from previous emergency landing conditions as it Start Printed Page 46241included dynamic testing of the seat and occupant protection criteria.

The SAE SEAT Committee was tasked with developing a standard that would provide a basis for meeting the 16g rule. SAE published AS 8049, that was incorporated into TSO-C127 in 1992. TSO-C127a was issued in 1998 after AS 8049A was published to further refine the dynamic seat standard. AS 8049 and AS 8049A contained the criteria for dynamic seats and still included criteria for static strength and design requirements.

Although seats were still being produced to the static 9g-standard in TSO-C39, the seat industry began to increase its production of TSO-C127 and TSO-C127a seats. So there were then, and currently still are, two standards—NAS 809 and AS8049—that addressed static 9g requirements.

In 2000, the FAA and industry formed a team to investigate and implement ways to streamline seat certification. This group recognized that two different standards addressing static strength and design considerations for seats was making the certification process more complicated than it needed to be. Therefore it was proposed that a new revision to TSO-C39 be issued to standardize the state criteria portion of the two standards.

It was decided that this could be successfully accomplished by referencing the static portion of AS 8049A for the proposed revision to TSO-C39. This will bring TSO-C39 in alignment with TSO-C127 and reflect the way industry currently uses the two standards. Most seat manufacturers are already using the static portion of AS 8049A as a basis for meeting airworthiness requirements not covered by the criteria in TSO-C39. Including the assessment under the TSO program will improve certification schedules. Additionally, AS 8049A continues to be reviewed and updated, and changes to AS 8049 will cover TSO-C127 seats as well as TSO-C39 seats.

How To Obtain Copies

A copy of the proposed TSO may be obtained via the information contained in section titled FOR FURTHER INFORMATION CONTACT, or the Internet at​certification/​aircraft/​TSOA.htm.

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Issued in Washington, DC on July 8, 2002.

David Hempe,

Manager, Aircraft Engineering Division Aircraft Certification Service.

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[FR Doc. 02-17576 Filed 7-11-02; 8:45 am]