AD 92-17-08

92-17-08 BOEING: Amendment 39-8337. Docket No. 92-NM-26-AD.

Applicability: Model 757 series airplanes; line numbers 1 through 454, inclusive, except 757PF (Freighters); certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To prevent seizure of the passenger door emergency power assist support bearings, which could delay the opening of an exit door during an emergency evacuation, accomplish the following:

(a) Prior to or upon the accumulation of 8,000 flight hours or within 1,500 flight hours after the effective date of this AD, whichever occurs later; and thereafter at intervals not to exceed 4,000 flight hours; perform a check of the emergency power assist cable travel to detect corroded or seized bearings, in accordance with Boeing Service Letter 757-SL-52-6, dated September 17, 1991, or Boeing Service Bulletin 757-52-0055, dated June 25, 1992. If discrepancies are detected, prior to further flight, correct themin accordance with the service letter or bulletin.

(b) Replacement of the existing alloy steel bearing with a new stainless steel bearing, bearing seal, and back-up ring, in accordance with Boeing Service Bulletin 757-52-0055, dated June 25, 1992; or in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate; constitutes terminating action for the requirements of this AD.

(c) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Seattle ACO, FAA, Transport Airplane Directorate. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Seattle ACO.

NOTE: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO.

(d)Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate the airplane to a location where the requirements of this AD can be accomplished.

(e) The checks and repairs shall be done in accordance with Boeing Service Letter 757-SL-52-6, dated September 17, 1991; or Boeing Service Bulletin 757-52-0055, dated June 25, 1992. 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 98124-2207. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street NW., 7th Floor, Suite 700, Washington, DC.

(f) This amendment becomes effective on September 28, 1992.