AD 91-07-03

91-07-03 LOCKHEED AERONAUTICAL SYSTEMS COMPANY: Amendment 39-6944. Docket No. 91-NM-17-AD. Applicability: All Model L-1011 series airplanes, certificated in any category.

Compliance: Required as indicated, unless previously accomplished.

To prevent structural failure of the aft pressure bulkhead, accomplish the following:

A. Except as provided in paragraph B. of this AD, within 30 days after the effective date of this AD, unless previously accomplished within the last 60 days, inspect the gore panels of the aft pressure bulkhead around the entire perimeter of the 1503618-145 (LH) and 1503618-143 (RH) reinforcing doublers, in accordance with Section 2. of the Accomplishment Instructions of Lockheed Service Bulletin 093-53-263, dated February 27, 1991.

B. For airplanes on which inspections of the aft pressure bulkhead have been accomplished in accordance with Lockheed Service Wire PSC/90-531176-OW, dated December 21, 1990, prior to the effective date of this AD: The remaining inspections required by paragraph A. of this AD may be deferred for a period not to exceed 3,000 landings following the effective date of this AD.

C. If cracks are found, prior to further flight, repair in accordance with a method approved by the Manager, Los Angeles Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate.

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, Los Angeles 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, Los Angeles ACO.

E. 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.

All persons affected by this directive who have not already received the appropriate service information from the manufacturer may obtain copies upon request to Lockheed Aeronautical Systems Company, 86 South Cobb Drive, Marietta, Georgia 30063, Attention: Commercial Order Administration, Dept 65-11, Building B-95, Zone 0577. This information may be examined at the FAA, Northwest Mountain Region, Transport Airplane Directorate, 1601 Lind Avenue S.W., Renton, Washington; or at the Los Angeles Aircraft Certification Office, 3229 East Spring Street, Long Beach, California.

This amendment (39-6944, AD 91-07-03) becomes effective on April 3, 1991.