AD 91-25-10

91-25-10 MCDONNELL DOUGLAS: Amendment 39-8111. Docket No. 91-NM-229-AD.

Applicability: Model DC-10-10 series airplanes, certificated in any category.

Compliance: Required as indicated, unless previously accomplished.

To prevent failure of the forward lower pressure bulkhead and consequent rapid decompression of the airplane, accomplish the following:

(a) Within 40 landings or 10 days after the effective date of this AD, whichever occurs earlier, unless previously accomplished within the last 210 landings, conduct a visual inspection of the forward lower pressure bulkhead at Fuselage Station Y=1156 as described in paragraphs (a)(1) and (a)(2) of this AD, as applicable. Repeat the visual inspections of the bulkhead thereafter at intervals not to exceed 250 landings.

(1) For Model DC-10-10 series airplanes, fuselage numbers 1 through 27, 30 through 43, 45 through 80, 83 through 86, 89 through 107, and 112 through 272, on which doublers have not been installed in accordance with McDonnell Douglas DC-10 Service Bulletin 53-104, dated July 28, 1978 (hereinafter referred to as "53-104"), accomplish the following: Clean and, under intense concentrated lighting, visually inspect the aft side of the web area on the right-hand side of the bulkhead between longerons 39 and 43, from the bulkhead tee cap up to the wing front spar.

(2) For Model DC-10-10 series airplanes, fuselage numbers 1 through 27, and 30 through 222, on which doublers have not been installed in accordance with McDonnell Douglas DC-10 Service Bulletin 53-102, dated August 15, 1977 (hereinafter referred to as "53-102"), accomplish the following: Clean and, under intense concentrated lighting, visually inspect either the aft or forward side of the web area on the left-hand side of the bulkhead between longerons 39 and 43, from the bulkhead tee cap up to the wing front spar.

(b) If cracks are found as a result of the inspections conducted in accordance with this AD,prior to further flight, repair in accordance with 53-102 or 53-104, as applicable.

(c) Installation of the doublers on the forward lower pressure bulkhead in accordance with 53-102 and 53-104 constitutes terminating action for the inspections required by this AD.

(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 Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. The request shall be forwarded through an FAA principal Maintenance Inspector (PMI), 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 unpressurized to a base in order to comply with the inspection requirements of this AD.

(f) The repair requirements shall be accomplished in accordance with McDonnell Douglas DC-10 Service Bulletin53-102, dated August 15, 1977; and McDonnell Douglas DC-10 Service Bulletin 53-104, dated July 28, 1978. 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 McDonnell Douglas Corporation, Technical Publications-Technical Administrative Support, C1-L5B, 3855 Lakewood Boulevard, Long Beach, California 90846. Copies may be inspected 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; or at the Office of the Federal Register, 1100 L Street N.W., Room 8401, Washington, D.C.

(g) This amendment (39-8111, AD 91-25-10) becomes effective on December 27, 1991.