Airworthiness Directive · Amendment 39-11863 · Lockheed Model L-1011-385 Series Airplanes
Lockheed Model L-1011-385 Series Airplanes
Model L-1011-385 series airplanes; serial numbers 1013 through 1250 inclusive; certificated in any category.
Note 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (c)(1) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.
This amendment supersedes an existing airworthiness directive (AD), applicable to certain Lockheed Model L-1011-385 series airplanes, that currently requires repetitive inspections to detect cracking of the canted pressure bulkhead at fuselage station (FS) 1212, and repetitive inspections to detect cracking of the web at the fastener rows of the vertical stiffener-to-web; and repair or replacement of the web with a new web, if necessary. This amendment requires that the initial inspections be accomplished at a reduced threshold. This amendment is prompted by a report of fatigue cracking of the canted pressure bulkhead at FS 1212. The actions specified by this AD are intended to detect and correct fatigue cracking of the canted pressure bulkhead at FS 1212, which could result in blowout of a panel between adjacent stiffeners and consequent cabin depressurization.
To detect and correct fatigue cracking of the canted pressure bulkhead at fuselage station (FS) 1212, which could result in blowout of a panel between adjacent stiffeners and consequent cabin depressurization, accomplish the following:
(a) Perform a detailed visual inspection to detect cracking of the entire aft surface of the canted pressure bulkhead at FS 1212 between left buttock line (LBL) 103 and right buttock line (RBL) 103; and perform an optical inspection using a borescope or other optical device to detect cracking of the web at the fastener rows of the vertical stiffener-to-web; in accordance with Lockheed Service Bulletin 093-53-277, dated July 2, 1996, or Revision 1, dated November 19, 1998; at the earlier of the times specified in paragraphs (a)(1) and (a)(2) of this AD. Thereafter, repeat these inspections at intervals not to exceed 1,000 flight cycles.
(1) Prior to the accumulation of 20,000 total flight cycles, or within 60 days after October 25, 1996 (the effective date of AD 96-20-10), whichever occurs later; or
(2) Prior to the accumulation of 18,000 total flight cycles, or within 60 days after the effective date of this AD, whichever occurs later.
Note 2: For the purposes of this AD, a detailed visual inspection is defined as: “An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids such as mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required.”
(b) If any cracking is found during any inspection required by paragraph (a) of this AD, prior to further flight, accomplish either paragraph (b)(1) or (b)(2) of this AD.
(1) Accomplish either paragraph (b)(1)(i) or (b)(1)(ii) of this AD, as applicable.
(i) If the cracking is found in an area that is specified Lockheed Service Bulletin 093-53-277, dated July 2, 1996, or Revision 1, dated November 19, 1998, repair in accordance with Section 53-11-00, Figure 854, of the L-1011 Structural Repair Manual (SRM), dated March 15, 1999. Accomplishment of a repair in accordance with this paragraph constitutes terminating action for the repetitive inspections required by paragraph (a) of this AD at the repaired location only. Or
(ii) If the cracking is found in an area that is not specified in Lockheed Service Bulletin 093-53-277, dated July 2, 1996, or Revision 1, dated November 19, 1998, repair in accordance with a method approved by the Manager, Atlanta Aircraft Certification Office (ACO), FAA, Small Airplane Directorate.
Note 3: Lockheed Repair Drawing LCC-7622-385 also is considered an acceptable source of service information for the accomplishment of the requirements of paragraph (b)(1)(i) of this AD.
(2) Replace the entire web with a new web in accordance with Lockheed Service Bulletin 093-53-277, dated July 2, 1996, or Revision 1, dated November 19, 1998. Such replacement constitutes terminating action for the repetitive inspections required by paragraph (a) of this AD.
(c)(1) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Atlanta ACO. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Atlanta ACO.
(2) Alternative methods of compliance, approved previously in accordance with AD 96-20-10, amendment 39-9776, are approved as alternative methods of compliance with paragraph (b) of this AD.
Note 4: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Atlanta ACO.
