AD 92-10-11

92-10-11 BOEING: Amendment 39-8245. Docket No. 91-NM-192-AD.

Applicability: Model 757 series airplanes, listed in Boeing Alert Service Bulletin 757-25A0112, dated July 18, 1991, certificated in any category.

Compliance: Required within the next 24 months after the effective date of this AD, unless previously accomplished.

To prevent damage to the floor beam at body station (BS) 1640, hydraulic system components, and flight control functions in the event of a sudden decrease in air pressure aft of the bulkhead lining, accomplish the following:

(a) Modify the soft bulkhead support structure at BS 1640 and replace the bulkhead lining in accordance with Boeing Alert Service Bulletin 757-25A0112, dated July 18, 1991.

(b) An alternative method of compliance or adjustment of the compliance time, which provides an acceptable level of safety, may be used when approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate.NOTE: The request should be forwarded through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Seattle ACO.

(c) Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base in order to comply with the requirements of this AD.

(d) The modification shall be done in accordance with Boeing Alert Service Bulletin 757-25A0112, dated July 18, 1991. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51. Copies may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, Washington; or at the Office of the Federal Register, 1100 L Street NW., Room 8401, Washington, DC.

(e) This amendment becomes effective on June 1, 1992.