AD 95-30646

[Federal Register Volume 60, Number 242 (Monday, December 18, 1995)] [Proposed Rules] [Pages 65032-65035] From the Federal Register Online via the Government Publishing Office [www.gpo.gov] [FR Doc No: 95-30646]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 95-NM-88-AD]

Airworthiness Directives; Lockheed Model L-1011-385 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the supersedure of an existing airworthiness directive (AD), applicable to all Lockheed Model L-1011- 385 series airplanes, that currently requires inspections to detect cracking of certain areas of the rear spar caps, web, skin, and certain fastener holes; and repair or modification, if necessary. That AD was prompted by reports of fatigue cracks in the caps of the wing rear spar inboard of inner wing station 346. The actions specified by that AD are intended to prevent rupture of the rear spar, which could result in extensive damage to the wing and fuel spillage. This action would add various improved inspections and follow-on actions, and would require that the initial inspections be accomplished at reduced thresholds.

DATES: Comments must be received by February 13, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-103, Attention: Rules Docket No. 95-NM-88-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal holidays. The service information referenced in the proposed rule may be obtained from Lockheed Aeronautical Systems Support Company, Field Support Department, Dept. 693, Zone 0755, 2251 Lake Park Drive, Smyrna, Georgia 30080. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Small Airplane Directorate, Atlanta Aircraft Certification Office, Campus Building, 1701 Columbia Avenue, Suite 2-160, College Park, Georgia.

FOR FURTHER INFORMATION CONTACT: Thomas Peters, Aerospace Engineer, Flight Test Branch, ACE-116A, FAA, Small Airplane Directorate, Atlanta Aircraft Certification Office, Campus Building, 1701 Columbia Avenue, Suite 2-160, College Park, Georgia 30337-2748; telephone (404) 305- 7367; fax (404) 305-7348.

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to participate in the making of the proposed 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 above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this notice may be changed in light of the comments received.

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Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed 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 summarizing each FAA-public contact concerned with the substance of this proposal will be filed in the Rules Docket. Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this notice must submit a self-addressed, stamped postcard on which the following statement is made: ``Comments to Docket Number 95-NM-88-AD.'' The postcard will be date stamped and returned to the commenter.

Availability of NPRMs

Any person may obtain a copy of this NPRM by submitting a request to the FAA, Transport Airplane Directorate, ANM-103, Attention: Rules Docket No. 95-NM-88-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

On August 26, 1993, the FAA issued AD 93-17-10, amendment 39-8681 (58 FR 54947, October 25, 1993), which is applicable to all Lockheed Model L-1011-385 series airplanes. That AD requires inspections to detect cracking of certain areas of the rear spar caps, web, skin, and certain fastener holes; and repair or modification, if necessary. That action was prompted by reports of fatigue cracks in the caps of the wing rear spar inboard of inner wing station (IWS) 346. The requirements of that AD are intended to prevent rupture of the rear spar, which could result in extensive damage to the wing and fuel spillage. Since the issuance of that AD, the FAA has received additional reports of fatigue cracking in the subject areas on these airplanes. The airplanes on which the cracking occurred had accumulated fewer landings than the number of landings specified as the inspection thresholds in AD 93-17-10.

Discussion of Relevant Service Information

Subsequent to the finding of this new cracking, the manufacturer issued, and the FAA reviewed and approved, Lockheed L-1011 Service Bulletin 093-57-203, Revision 4, dated March 27, 1995. The revised service bulletin describes procedures for inspections to detect cracking in certain areas of the rear spar caps, web, skin, and certain fastener holes at earlier inspection thresholds than those specified previously. The service bulletin revision describes the following various improved inspection procedures and follow-on actions: 1. Repetitive X-ray (radiographic) inspections to detect cracking of the upper and lower caps of the rear spar and of the associated web and skin areas between IWS 231 and IWS 343. The inspection procedure specified in the revised service bulletin has been changed from that described in Revision 3 to clarify the location for the X-ray tube head for certain exposures. 2. Repetitive eddy current surface scan inspections to detect cracking of the upper spar cap-to-skin and the upper spar cap-to-web attachment areas around the fasteners from IWS 310 to the main landing gear (MLG) trunnion fitting at approximately IWS 343. 3. A bolt hole eddy current inspection to detect cracking in the 1\1/8\-inch diameter fastener hole located inboard of IWS 343. The service bulletin specifies that this inspection is accomplished at an initial inspection threshold only. (However, the service bulletin also specifies that this inspection must be accomplished on any fastener hole where the fastener is removed for repair or replacement.) 4. For airplanes on which cracking is found during the bolt hole eddy current inspection of the 1\1/8\-inch diameter fastener hole located inboard of IWS 343, the service bulletin describes procedures for a bolt hole eddy current inspection to detect cracking at the four \5/8\-inch fastener locations directly below the 1\1/8\-inch fastener. 5. For airplanes on which Option iv or v of Lockheed Repair Procedure LCC-7622-368 has not been accomplished, the service bulletin describes procedures for subsequent repetitive ultrasonic inspections to detect cracking in the fastener hole. These inspections are performed in conjunction with eddy current surface scan inspections to detect cracking of the upper horizontal edge of the rear spar web, \1/ 2\-inch each side of the inboard edge of the MLG trunnion fitting. 6. Repetitive low frequency eddy current ring probe inspections to detect cracking of the upper cap/skin of the rear spar between IWS 310 to IWS 326 and the cap/web fasteners. Since the issuance of AD 93-17-10, the FAA has also reviewed and approved later revisions of certain service information specified in paragraph (d) of that AD as an alternative method of repairing confirmed findings of cracking, as follows: 1. Lockheed L-1011 Service Bulletin 093-57-196, Revision 6, dated December 6, 1994, and Lockheed L-1011 Service Bulletin Change Notification 093-57-196, R6-CN1, dated August 22, 1995. 2. Lockheed L-1011 Service Bulletin 093-57-184, Revision 7, dated December 6, 1994, and Lockheed L-1011 Service Bulletin Change Notification 093-57-196, R7-CN1, dated August 22, 1995. These service bulletins describe procedures for modification of the rear spar upper and lower caps between IWS 228 and 346. Among other things, these service bulletin revisions were issued to standardize the rework of fastener holes, add new instructions to refer to drawings to accomplish the modification, clarify miscellaneous information, and to reference certain service information for web damage extending beyond IWS 327.

Discussion of the Proposed Action

Since an unsafe condition has been identified that is likely to exist or develop on other products of this same type design, the proposed AD would supersede AD 93-17-10 to continue to require inspections to detect cracking of certain areas of the rear spar caps, web, skin, and certain fastener holes; and repair or modification, if necessary. The proposed AD would add various improved inspections and follow-on actions, and would require that the initial inspections be accomplished at reduced thresholds. The inspections, follow-on actions, and modification would be required to be accomplished in accordance with the service bulletin described previously. The repair would be required to be accomplished in accordance with a method approved by the FAA or in accordance with the Lockheed Model L-1011 Structural Repair Manual. Operators should note that only the inspection procedures (and follow-on actions) described in Lockheed L-1011 Service Bulletin 093- 57-203 would be required by this proposal. In a separate AD action [AD 94-05-01, amendment 39-8839 (59 FR 10275, March 4, 1994)], the FAA previously addressed the portion of that service bulletin that deals with the modification

Cost Impact

There are approximately 236 Model L-1011-385 series airplanes of the affected design in the worldwide fleet. The FAA estimates that 118 airplanes of U.S. registry would be affected by this proposed AD. The actions that are currently required by AD 93-17-10 take

[[Page 65034]] approximately 21 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact on U.S. operators of the actions currently required is estimated to be $148,680, or $1,260 per airplane. The new actions that are proposed in this AD action would take approximately 64 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. [This work hour estimate assumes that X-ray inspections are done of both upper and lower caps, and that the ultrasonic inspection indicates cracking in each of five bolt holes (per wing), thus requiring subsequent bolt hole eddy current inspections to confirm crack findings. The estimate includes inspections of both wings.] Based on these figures, the cost impact on U.S. operators of the proposed requirements of this AD is estimated to be $453,120, or $3,840 per airplane. The cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the current or proposed requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted.

Regulatory Impact

The regulations proposed herein would 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 proposal would not have sufficient federalism implications to warrant the preparation of a Federalism Assessment. For the reasons discussed above, I certify that this proposed regulation (1) is not a ``significant regulatory action'' under Executive Order 12866; (2) is not a ``significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) if promulgated, will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. A copy of the draft regulatory evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting 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.

The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39--AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40101, 40113, 44701.

Sec. 39.13 [Amended]

2. Section 39.13 is amended by removing amendment 39-8681 (58 FR 54947, October 25, 1993), and by adding a new airworthiness directive (AD), to read as follows:

Lockhead Aeronautical Systems Company: Docket 95-NM-88-AD. Supersedes AD 93-17-10, Amendment 39-8681.

Applicability: All Model L-1011-385-1, L-1011-385-1-14, L-1011- 385-1-15, and L-1011-385-3 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 otherwise 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 (d) 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.

Note 2: Paragraphs (a)(1) and (b) of this AD restate the requirement for repetitive inspections and follow-on actions contained in paragraphs (a) and (b) of AD 93-17-10. Therefore, for operators who have previously accomplished at least the initial inspection in accordance with AD 93-17-10, paragraphs (a)(1) and (b) of this AD require that the next scheduled inspection be performed within 2,000 flight cycles after the last inspection performed in accordance with paragraphs (a) and (b) of AD 93-17-10.

To prevent rupture of the rear spar, which could result in extensive damage to the wing and fuel spillage, accomplish the following: (a) Perform inspections and various follow-on actions to detect cracking in the areas specified in and in accordance with Part II of the Accomplishment Instructions of the Lockheed service documents listed below. After the effective date of this AD, the inspections and follow-on actions shall be performed only at the times specified in and in accordance with Revision 4 of Lockheed L-1011 Service Bulletin 093-57-203. [The inspections and follow-on actions include: repetitive X-ray (radiographic) inspections; repetitive eddy current surface scan inspections; bolt hole eddy current inspections at various locations; repetitive ultrasonic inspections in conjunction with eddy current surface scan inspections (for certain airplanes); and repetitive low frequency eddy current ring probe inspections.] Lockheed L-1011 Service Bulletin 093-57-203, Revision 3, dated October 28, 1991; or Lockheed L-1011 Service Bulletin Service Bulletin 093- 57-203, Revision 3, dated October 28, 1991, as amended by Lockheed L-1011 Service Bulletin Change Notification 093-57-203, R3-CN1, dated June 22, 1992; or Lockheed L-1011 Service Bulletin 093-57-203, Revision 4, dated March 27, 1995. (1) For airplanes on which the inspections required by AD 93-17- 10, amendment 39-8681, have been initiated prior to the effective date of this AD: Perform the inspections and follow-on actions at the times specified in Table I of Lockheed L-1011 Service Bulletin Change Notification 093-57-203, R3-CN1, dated June 22, 1992, or within 6 months after November 24, 1993 (the effective date of AD 93-17-10, amendment 39-8681), whichever occurs later.

Note 3: As allowed by the phrase, ``unless accomplished previously,'' if the inspections and follow-on actions required by this paragraph were conducted prior to November 24, 1993, in accordance with Lockheed L-1011 Service Bulletin 093-57-203, Revision 2, dated January 25, 1991, those inspections need not be repeated.

(2) For airplanes on which the inspections required by AD 93-17- 10, amendment 39-8681, have not been initiated prior to the effective date of this AD: Perform the inspections and follow-on actions at the times specified in Table I of Lockheed L-1011 Service Bulletin 093-57-203, Revision 4, dated March 27, 1995, or within 6 months after the effective date of this AD, whichever occurs later. (b) If no cracking is found, perform the repetitive inspections and follow-on actions specified in the Accomplishment Instructions of the Lockheed service documents listed below thereafter at intervals not to exceed 2,000 flight cycles. After the effective date of this AD, the inspections and follow-on actions shall be performed only in accordance with Revision 4 of Lockheed L-1011 Service Bulletin 093-57-203. Lockheed L-1011 Service Bulletin 093-57-203, Revision 3, dated October 28, 1991; or Lockheed L-1011 Service Bulletin 093-57-203, Revision 3, dated October 28, 1991, as amended by Lockheed L-1011 Service Bulletin Change Notification 093-57-203, R3-CN1, dated June 22, 1992; or Lockheed L-1011 Service Bulletin 093-57-203, Revision 4, dated March 27, 1995;

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(c) If any finding of cracking is confirmed, prior to further flight, accomplish paragraph (c)(1), (c)(2), or (c)(3) of this AD. (1) Repair the cracked area in accordance with a method approved by the Manager, Atlanta Aircraft Certification Office (ACO), FAA, Small Airplane Directorate. Thereafter, perform the repetitive inspections and follow-on actions required by paragraph (b) of this AD. Or (2) Repair the rear spar upper and lower caps between IWS 228 and 346 in accordance with the Lockheed Model L-1011 Structural Repair Manual. Thereafter, perform the repetitive inspections and follow-on actions required by paragraph (b) of this AD. Or (3) Modify the rear spar upper and lower caps between IWS 228 and 346 in accordance with the Lockheed service bulletins listed below, as applicable. Accomplishment of the modification constitutes terminating action for the requirements of this AD. Lockheed L-1011 Service Bulletin 093-57-184, Revision 7, dated December 6, 1994, as amended by Change Notification 093-57- 184, R7-CN1, dated August 22, 1995; or Lockheed L-1011 Service Bulletin 093-57-196, Revision 6, dated December 6, 1994, as amended by Change Notification 093-57- 196, R6-CN1, dated August 22, 1995; or Lockheed L-1011 Service Bulletin 093-57-203, Revision 4, dated March 27, 1995.

Note 4: Accomplishment of the modification specified in paragraph (c)(3) of this AD prior to the effective date of this AD in accordance with the following Lockheed service bulletins, as applicable, is considered to be in compliance with this paragraph:

Lockheed L-1011 Service Bulletin 093-57-184, Revision 6, dated October 28, 1991; Lockheed L-1011 Service Bulletin 093-57-184, Revision 7, dated December 6, 1994; Lockheed L-1011 Service Bulletin 093-57-196, Revision 5, dated October 28, 1991; Lockheed L-1011 Service Bulletin 093-57-196, Revision 6, dated December 6, 1994; Lockheed L-1011 Service Bulletin 093-57-203, Revision 3, dated October 28, 1991; or Lockheed L-1011 Service Bulletin 093-57-203, Revision 3, dated October 28, 1991, as amended by Change Notification 093-57- 203, R3-CN1, dated June 22, 1992. (d) 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.

Note 5: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Atlanta ACO.

(e) 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.

Issued in Renton, Washington, on December 11, 1995. Darrell M. Pederson, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 95-30646 Filed 12-15-95; 8:45 am] BILLING CODE 4910-13-U