87-07-07 BRITISH AEROSPACE: Amendment 39-5589. Applies to all Model BAC 1- 11 200 and 400 series airplanes, certificated in any category. Compliance is required prior to the accumulation of 12,000 landings, or within the next 1,500 landings after the effective date of this AD, whichever occurs later.
To prevent failure of the keel structure to carry design loads due to structural crack propagation in the keel beam lateral diaphragm, accomplish the following, unless previously accomplished:
A. Inspect, and repair or replace, as necessary, the keel beam lateral diaphragm assembly in accordance with BAC 1-11 Alert Service Bulletin 53-A-PM5918, dated May 6, 1986.
B. Repeat the requirements of paragraph A., above, at intervals not to exceed 3,600 landings.
C. An alternate means of compliance or adjustment of the compliance time, which provides an acceptable level of safety, may be used when approved by the manager, Standardization Branch, ANM-113, FAA, NorthwestMountain Region.
D. Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base for the accomplishment of the requirements of this AD.
All persons affected by this directive who have not already received the appropriate service document from the manufacturer may obtain copies upon request to British Aerospace, Inc., Librarian, P.O. Box 17414, Dulles International Airport, Washington, D.C. 20041. This document may be examined at the FAA, Northwest Mountain Region, 17900 Pacific Highway South, Seattle, Washington, or the Seattle Aircraft Certification Office, 9010 East Marginal Way South, Seattle, Washington.
This amendment becomes effective May 1, 1987.