AD 96-07-13

This amendment supersedes 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, web, and skin 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 amendment adds various improved inspections and follow-on actions, and requires that the initial inspections be accomplished at reduced thresholds.

Final rule.

96-07-13 LOCKHEED AERONAUTICAL SYSTEMS COMPANY: Amendment 39-9563. 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 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 (d) 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.

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 AD93-17-10, 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;

(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 October28, 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.

(f) Certain actions shall be done in accordance with Lockheed L-1011 Service Bulletin 093-57-203, Revision 4, dated March 27, 1995. The modification, if accomplished, shall be done in accordance with 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. The incorporation by reference of these documents was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Certain other actions shall be done in accordance with Lockheed L-1011 Service Bulletin 093-57-203, Revision 3, dated October 28, 1991; and 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. The incorporation by reference of these documents was approved previously by the Director of the Federal Register, in accordance with 5 U.S.C. 552(a) and 1 CFR part 5,1 as of November 24, 1993 (58 FR 54947, October 25, 1993). Copies may be obtained from Lockheed Aeronautical Systems Support Company, Field Support Department, Dept. 693, Zone 0755, 2251 Lake Park Drive, Smyrna, Georgia 30080. Copies may be inspected 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; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

(g) This amendment becomes effective on May 15, 1996.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by superseding 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, was published in the Federal Register on December 18, 1995 (60 FR 65032). The action proposed 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 action proposed to add various improved inspections and follow-on actions, and to require that the initial inspections be accomplished at reduced thresholds.

Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received.

Four commenters support the proposed rule.

Two commenters request that the proposed rule be issued without change, but that the FAAissue subsequent rulemaking to require a reduced repetitive inspection interval. One commenter expresses concern that analytical data and service experience do not support the repetitive inspection interval of 2,000 flight cycles recommended in Revision 4 of Lockheed L-1011 Service Bulletin 093-57-203. The commenter states that two inspection opportunities should be provided to detect cracks prior to the time at which those cracks reach critical flaw size; the proposed inspection interval will not allow two inspections to be conducted during the period between the point at which the crack becomes detectable using the specified inspection methods and the point at which the crack reaches critical length. The second commenter, the manufacturer, indicates that analysis of an incident that occurred subsequent to the issuance of Revision 4 of the service bulletin revealed a failure mode that had not been evaluated fully. The manufacturer advises that it intends to revise the service bulletin to recommend that the repetitive inspection intervals be reduced and to change the inspection requirements to ensure timely detection of cracks.

The FAA concurs with the commenters' request. The FAA may consider additional rulemaking to address the issues discussed by the commenters once an acceptable inspection interval and other inspections have been identified.

One commenter requests that the Summary section of the preamble to the proposed rule be revised to clarify that fatigue cracks were found in the web and skin, as well as the caps, of the wing rear spar inboard of inner wing station 346. The FAA concurs, and has made this change to the pertinent language in the preamble to this final rule.

After careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule with the changes previously described. The FAA has determined that these changes will neitherincrease the economic burden on any operator nor increase the scope of the AD.

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 will be affected by this proposed AD.

The actions that are currently required by AD 93-17-10 take 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 required by this new AD will 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 new 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 requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted.

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.

For the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under Executive Order 12866; (2) is not a "significant rule" under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it 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, Incorporation by reference, 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:

PART 39 - AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
Authority: 49 USC 106(g), 40113, 44701.

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), amendment 39-9563, to read as follows: