AD 92-08-12

92-08-12 BOEING: Amendment 39-8223. Docket No. 91-NM-95-AD.

Applicability: Model 747-400 series airplanes, up to and including line position 839, certificated in any category.

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

To preclude cross connection of cargo compartment and engine fire protection wiring and plumbing during maintenance, accomplish the following:

(a) For airplanes identified in Boeing Service Bulletin 747-26-2143, Revision 1, dated August 15, 1991: Modify the cargo compartment fire extinguishing system plumbing and wiring in accordance with that service bulletin.

(b) For airplanes identified in Boeing Service Bulletin 747-26-2164, dated February 14, 1991: Modify the engine fire control module in accordance with that service bulletin.

(c) For airplanes identified in Boeing Service Bulletin 747-26-2168, dated March 28, 1991: Modify the cargo compartment smoke detectionsystem wiring in accordance with that service bulletin.

(d) 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. The request shall be forwarded through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Seattle ACO.

(e) 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.

(f) The modifications shall be done in accordance with Boeing Service Bulletin 747-26-2164, dated February 14, 1991; Boeing Service Bulletin 747-26-2168, dated March 28, 1991; and Boeing Service Bulletin 747-26-2143, Revision 1, dated August 15, 1991, which includes the following list of effective pages:

Page Number Revision Level Date 1, 3-8, 18-20, 33, 45-50, 1 August 15, 1991 54, 61-62, 64-87

2, 9-17, 21-32, 34-44, (original) December 20, 51-53, 55-60, 63 1990

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.

(g) This amendment becomes effective on May 29, 1992.