91-20-05 BRITISH AEROSPACE: Amendment 39-8039. Docket No. 91-NM-110-AD.
Applicability: All Model BAC 1-11 200 and 400 series airplanes, certificated in any category.
Compliance: Required as indicated, unless previously accomplished.
To prevent loss of cabin pressurization, accomplish the following:
(a) For airplanes operated to a maximum of 7.5 pounds per square inch (psi) cabin pressure differential: Prior to the accumulation of 24,000 landings, or within 3,000 landings after the effective date of this AD, whichever occurs later; and thereafter at intervals not to exceed 3,200 landings; perform a visual inspection of the skin and cleats at the front and rear extremities of the twelve stiffeners to detect cracks, in accordance with British Aerospace Alert Service Bulletin 53-A-PM5990, Issue 1, dated January 7, 1991.
(b) For airplanes modified for operation to a maximum of 8.2 psi cabin pressure differential: Prior to the accumulation of 16,000 landings, or within 2,000 landings after the effective date of this AD, whichever occurs later; and thereafter at intervals not to exceed 2,400 landings; perform a visual inspection of the skin and cleats at the front and rear extremities of the twelve stiffeners to detect cracks, in accordance with the British Aerospace Alert Service Bulletin 53-A-PM5990, Issue 1, dated January 7, 1991.
(c) If skin cracks are found, prior to further flight, repair in accordance with a procedure approved by the Manager, Standardization Branch, ANM-113, FAA, Transport Airplane Directorate. If cleat cracks are found, prior to further flight, replace cracked cleats by installing a new part having post-Modification PM5629 Part (a) configuration.
(d) For all airplanes: Prior to the accumulation of 85,000 landings, install Modification PM5629 Part (a) in accordance with British Aerospace Alert Service Bulletin 53-A-PM5990, Issue 1, dated January 7, 1991.
(e) Installation of Modification PM5629 Part(a), in accordance with British Aerospace Alert Service Bulletin 53-A-PM5990, Issue 1, dated January 7, 1991, constitutes terminating action for the repetitive inspections required by paragraphs (a) and (b) of this AD.
(f) 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, Standardization Branch, ANM-113, 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, Standardization Branch, ANM-113.
(g) 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.
(h) The inspection, repair, and installation requirements shall be done in accordance with British Aerospace Alert Service Bulletin 53-A-PM5990, Issue 1, dated January 7, 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 British Aerospace, PLC, Librarian for Service Bulletins, P.O. Box 17414, Dulles International Airport, Washington, D.C. 20041-0414. Copies may be inspected at the FAA, Transport Airplane Directorate, Renton, Washington; or at the Office of the Federal Register, 1100 L Street N.W., Room 8401, Washington, D.C.
This amendment (39-8039, AD 91-20-05) becomes effective on November 7, 1991.