# AD 95-18-52: Airworthiness Directives; Lockheed Model L-1011-385 Series Airplanes - Type: Airworthiness directive - Effective: September 28, 1995 - Published: September 13, 1995, 60 FR 47464–47466 - Issued as: Final rule; request for comments - Superseded by: Nothing supersedes this AD - Amendment: 39-9366 - Docket: 95-NM-153-AD - Official PDF: https://openairdocs.org/files/sha256/71/fa/71fa48ff61205898c7332215d594dd108ae18b973e332c74f7049b64e50b9db0 (from https://www.govinfo.gov/content/pkg/FR-1995-09-13/pdf/95-22591.pdf) - Federal Register: https://www.federalregister.gov/documents/1995/09/13/95-22591/airworthiness-directives-lockheed-model-l-1011-385-series-airplanes - Page: https://openairdocs.org/ad/95-18-52 ## Summary This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) T95-18-52 that was sent previously to all known U.S. owners and operators of Lockheed Model L-1011-385 airplanes by individual telegrams. This AD requires visual inspections to detect cracking of the fittings that attach the aft pressure bulkhead to the fuselage stringers, replacement of cracked fittings, and repair of adjacent structure if found to be cracked. This amendment is prompted by reports of cracks found in these fittings. The actions specified by this AD are intended to prevent failure of these fittings due to fatigue cracking; such failure could result in rapid decompression of the airplane during flight. ## The airworthiness directive ### PART 39--AIRWORTHINESS DIRECTIVES 1. The authority citation for part 39 continues to read as follows: Authority: 49 USC 106(g), 40101, 40113, 44701. ### Sec. 39.13 [Amended] 2. Section 39.13 is amended by adding the following new airworthiness directive: 95-18-52 LOCKHEED: Amendment 39-9366. Docket 95-NM-153-AD. Applicability: All Model L-1011-385 series airplanes, 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 use the authority provided in paragraph (f) of this AD to request approval from the FAA. This approval may address either no action, if the current configuration eliminates the unsafe condition; or different actions necessary to address the unsafe condition described in this AD. Such a request should include an assessment of the effect of the changed configuration on the unsafe condition addressed by this AD. In no case does the presence of any modification, alteration, or repair remove any airplane from the applicability of this AD. Compliance: Required as indicated, unless accomplished previously. To prevent fatigue cracking which could lead to failure of the fittings that attach the aft pressure bulkhead to the fuselage stringers, and could result in rapid decompression of the airplane during flight, accomplish the following: ### (a) (a) Perform a detailed visual inspection to detect cracking of the fittings that attach the aft pressure bulkhead to the fuselage stringers (hereinafter referred to as ``fittings'') at stringers 1 through 10 (right side) and at stringers 64 through 56 (left side), at the later of the times specified in either paragraph (a)(1) or (a)(2) of this AD. (1) Prior to the accumulation of 20,000 total flight cycles; or (2) Within the next 25 flight cycles or 10 days after the effective date of this AD, whichever occurs earlier. ### (b) (b) If cracking is detected in the fitting at either stringer 10 or stringer 56, prior to further flight, perform a detailed visual inspection to detect cracking of the next adjacent fitting (i.e., at stringer 11 or 55). If cracking is detected in that fitting, prior to further flight, perform a detailed visual inspection to detect cracking of the next adjacent fitting (i.e., at stringer 12 or 54). If cracking is detected in that fitting, prior to further flight, continue to perform detailed visual inspections to detect cracking of the next adjacent fitting(s) until such a fitting is found to be free of cracks. ### (c) (c) If any cracked fitting is detected during the inspections required by either paragraph (a) or (b) of this AD, prior to further flight, accomplish the requirements of paragraphs (c)(1) and (c)(2) of this AD. (1) Replace the cracked fitting with a new fitting, or with a serviceable fitting on which a detailed visual inspection has been performed previously to detect cracking and has been found to be free of cracks; and (2) Perform a detailed visual inspection to detect cracking in the radius at the lower end of the vertical leg of the bulkhead T-shaped frame between the stringer locations on either side of the stringer having the cracked fitting. If any cracked T-shaped frame is detected, prior to further flight, repair in accordance with a method approved by the Manager, Atlanta Aircraft Certification Office, FAA, Small Airplane Directorate. ### (d) (d) Repeat the inspections and other necessary actions required by paragraphs (a), (b), and (c) of this AD at intervals not to exceed 1,800 flight cycles or 3,000 flight hours, whichever occurs earlier. ### (e) (e) Within 10 days after accomplishing the initial inspections required by paragraphs (a) and (c) of this AD, submit a report of the inspection results (both positive and negative findings) to the Manager, Atlanta Aircraft Certification Office, FAA, Small Airplane Directorate, Campus Building, 1701 Columbia Avenue, suite 2-160, College Park, Georgia 30337-2748; telephone (404) 305-7340; fax (404) 305-7348. The report must include, at a minimum, the total number of flight cycles accumulated on the airplane having the cracked fitting or cracked T-shaped frame, and identification of the location on the airplane where the cracked fitting or T-shaped frame was found, if any. Information collection requirements contained in this regulation have been approved by the Office of Management and Budget (OMB) under the provisions of the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have been assigned OMB Control Number 2120-0056. ### (f) (f) 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 Aircraft Certification Office (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. Note 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Atlanta ACO. ### (g) (g) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished. ### (h) (h) This amendment becomes effective on September 28, 1995, to all persons except those persons to whom it was made immediately effective by telegraphic AD T95-18-52, issued on August 29, 1995, which contained the requirements of this amendment. Issued in Renton, Washington, on September 6, 1995. Darrell M. Pederson, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. ## Rule preamble ### Dates Effective September 28, 1995, to all persons except those persons to whom it was made immediately effective by telegraphic AD T95-18-52, issued August 29, 1995, which contained the requirements of this amendment. Comments for inclusion in the Rules Docket must be received on or before November 13, 1995. ### Addresses Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-103, Attention: Rules Docket No. 95-NM-153-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Information concerning this AD may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Atlanta Aircraft Certification Office, Small Airplane Directorate, Campus Building, 1701 Columbia Avenue, Suite 2-160, College Park, Georgia. ### For further information contact Thomas B. Peters, Aerospace Engineer, FAA, Atlanta Aircraft Certification Office, Small Airplane Directorate, Campus Building, 1701 Columbia Avenue, Suite 2-160, College Park, Georgia 30337-2748; telephone (404) 305-7367; fax (404) 305-7348. ### Supplementary information On August 29, 1995, the FAA issued telegraphic AD T95-18-51, which is applicable to Lockheed Model L-1011-385 series airplanes. The FAA recently received a report from an operator of Lockheed Model L-1011-385 series airplanes indicating that the aft pressure bulkhead on an airplane failed while it was in flight, which resulted in rapid decompression of the airplane. This airplane had accumulated 52,010 hours time-in-service and 25,721 total flight cycles. Investigation revealed that 19 of the fittings that attach the aft pressure bulkhead to the fuselage stringers at stringers 10 through 55 were severed on this airplane. Additionally, the vertical leg of the bulkhead outer tee was cracked between these stringers. The cause of the cracking of the fittings has been attributed to fatigue. Subsequent inspections of 15 additional airplanes in the fleet revealed cracking in the fittings of 5 of those airplanes; however, none of those fittings were severed. Fatigue cracking, if not detected and corrected in a timely manner, could lead to failure of the fittings that attach the aft pressure bulkhead to the fuselage stringers, and subsequently could result in rapid decompression of the airplane during flight. Since the unsafe condition described is likely to exist or develop on other airplanes of the same type design, the FAA issued Telegraphic AD T95-18-52 to ensure that cracked fittings are identified and replaced in a timely manner. The AD requires a detailed visual inspection to detect cracking of the fittings that attach the aft pressure bulkhead to the fuselage stringers at stringers 1 through 10 (on the right side of the airplane) and at stringers 64 through 56 (on the left side of the airplane). If cracking is found in any fitting, the fitting must be replaced and an additional detailed visual inspection must be performed to detect cracking in the radius at the lower end of the vertical leg of the bulkhead T-shaped frame. If cracking is found in the T-shaped frame, the cracked frame must be repaired. Additionally, if cracking is detected in the fittings of either stringer 10 or 56, the fitting(s) in the adjacent outboard stringer(s) must be inspected until the fittings are found to be free of cracks. The detailed visual inspections of the fittings and necessary follow-on actions are to be repeated at specified intervals. This AD also requires that operators submit, to the FAA, a report of the findings of their inspections. This is considered to be interim action until final action is identified, at which time the FAA may consider further rulemaking. Since it was found that immediate corrective action was required, notice and opportunity for prior public comment thereon were impracticable and contrary to the public interest, and good cause existed to make the AD effective immediately by individual telegrams issued on August 29, 1995, to all known U.S. owners and operators of Lockheed Model L-1011-385 series airplanes. These conditions still exist, and the AD is hereby published in the Federal Register as an amendment to section 39.13 of the Federal Aviation Regulations (14 CFR 39.13) to make it effective to all persons. ### Comments Invited Although this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this rule by submitting such written data, views, or arguments as they may desire. Communications shall identify the Rules Docket number and be submitted in triplicate to the address specified under the caption ADDRESSES. All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed. Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket. Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this rule must submit a self-addressed, stamped postcard on which the following statement is made: ``Comments to Docket Number 95-NM-153-AD.'' The postcard will be date stamped and returned to the commenter. The regulations adopted herein will not have substantial direct effects on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government. Therefore, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment. The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and that it is not a ``significant regulatory action'' under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket. A copy of it, if filed, may be obtained from the Rules Docket at the location provided under the caption ADDRESSES. ### List of Subjects in 14 CFR Part 39 Air transportation, Aircraft, Aviation safety, Safety. ### Adoption of the Amendment Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows: No proposed rule in this release led to it. Its text cites no advisory circulars or STCs. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.