AD 99-13-08

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 and other discrepancies of certain web-to-cap fasteners of the rear spar between inner wing stations 310 and 343, and of the web area around those fasteners; and various follow-on actions. That AD also provides for an optional modification, which, if accomplished, would defer the initiation of the inspections for a certain period of time. This amendment requires accomplishment of the previously optional modification. This amendment is prompted by an FAA determination that the optional terminating modification specified in the existing AD must be accomplished within a specified period of time to ensure an acceptable level of safety of the affected fleet. The actions specified by this AD are intended to prevent fatigue cracking in the web of the rear spar of the wing, which could result in failure of the rear spar of the wing and consequent fuel spillage.

Final rule

99-13-08 LOCKHEED: Amendment 39-11202. Docket 97-NM-11-AD. Supersedes AD 96-12-24, Amendment 39-9667.

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 request approval for an alternative method of compliance in accordance with paragraph (h)(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.

Compliance: Required as indicated, unless accomplishedpreviously.

To prevent fatigue cracking on the web of the rear spar of the wing, which could result in failure of the rear spar of the wing and consequent fuel spillage, accomplish the following:

RESTATEMENT OF ACTIONS REQUIRED BY AD 96-12-24, AMENDMENT 39-9667:
(a) Perform a visual inspection to detect signs of cracking and other discrepancies (i.e., corrosion, fastener looseness, nicks, scratches, or other surface damage) of the web-to-cap fasteners of the rear spar between inner wing stations (IWS) 310 and 343, as specified in Figure 2 of Lockheed Service Bulletin 093-57-218, dated April 11, 1996, or Revision 1, dated September 9, 1996; and of the web area around those fasteners; in accordance with Part I of the Accomplishment Instructions of that service bulletin. Perform the inspection at the applicable time specified in paragraph (a)(1) or (a)(2) of this AD.

(1) Except as provided by paragraph (a)(2) of this AD: Perform the initial inspection prior to the accumulation of the number of landings specified as the "inspection threshold" in Table I of Lockheed Service Bulletin 093-57-218, dated April 11, 1996, or Revision 1, dated September 9, 1996, or within 10 days after June 27, 1996 (the effective date of AD 96-12-24, amendment 39-9667), whichever occurs later.

(2) For airplanes on which the wing rear spar has been modified prior to June 27, 1996, in accordance with one of the Lockheed service bulletins listed in paragraph (a)(2)(ii) of this AD, accomplish the inspection as follows:

(i) Perform the initial inspection prior to the accumulation of the number of landings specified as the "inspection threshold" in Table I of Lockheed Service Bulletin 093-57-218, dated April 11, 1996, or Revision 1, dated September 9, 1996, calculated from the time the wing rear spar was modified (rather than from the date of manufacture of the airplane), or within 10 days after June 27, 1996, whichever occurs later.

(ii) This paragraph applies to airplanes on which the wing rear spar has been modified in accordance with one of the following service bulletins:

Lockheed Service Bulletin 093-57-184, Revision 6, dated October 28, 1991, or Revision 7, dated December 6, 1994; or

Lockheed Service Bulletin 093-57-196, Revision 5, dated October 28, 1991, or Revision 6, dated December 6, 1994; or

Lockheed Service Bulletin 093-57-203, Revision 3, dated October 28, 1991, or Revision 4, dated March 27, 1995; or

Lockheed Service Bulletin 093-57-215, dated April 11, 1996.

(b) If no sign of cracking or other discrepancy is found during the inspection required by paragraph (a) of this AD, repeat that inspection thereafter at intervals not to exceed the number of landings specified as the "repeat visual inspection interval" in Table I of Lockheed Service Bulletin 093-57-218, dated April 11, 1996, or Revision 1, dated September 9, 1996.

(c) If any sign of cracking is found during an inspection required by paragraph(a) or (b) of this AD, prior to further flight, perform either eddy current surface scan inspections, or bolt hole eddy current inspections, as appropriate, to confirm cracking, in accordance with Lockheed Service Bulletin 093-57-218, dated April 11, 1996, or Revision 1, dated September 9, 1996.

(1) If no cracking is confirmed, repeat the inspection specified in paragraph (a) of this AD at intervals not to exceed the number of landings specified as the "repeat visual inspection interval" in Table I of the service bulletin.

(2) If any cracking is confirmed, prior to further flight, repair it in accordance with the service bulletin.

NEW REQUIREMENTS OF THIS AD:
Modification
(d) Except as provided by paragraph (e) or (f) of this AD, as applicable: Within 12 months after the effective date of this AD, modify the web-to-cap fastener holes of the rear spar between IWS 299 and IWS 343 in accordance with Part II of the Accomplishment Instructions of Lockheed Service Bulletin 093-57-218, Revision 1, dated September 9, 1996. Within 5,000 landings following accomplishment of the modification, perform the visual inspection required by paragraph (a) of this AD. Thereafter, repeat that inspection at intervals not to exceed the number of landings specified as the "repeat visual inspection interval" in Table I of Lockheed Service Bulletin 093-57-218, Revision 1, dated September 9, 1996.

(e) For Model L-1011-385-3 series airplanes: Accomplishment of the modification specified in paragraph (e)(1) or (e)(2) of this AD, within 12 months after the effective date of this AD, constitutes an acceptable alternative to the modification specified in paragraph (d) of this AD.

(1) Modify the upper and lower caps of the rear spar between IWS 228 and IWS 346 in accordance with Part I of the Accomplishment Instructions of Lockheed Service Bulletin 093-57-203, Revision 3, dated October 28, 1991; or Revision 4, dated March 27, 1995. Within 5,000 landings following accomplishment of the modification, perform the visual inspection required by paragraph (a) of this AD. Thereafter, repeat that inspection at intervals not to exceed the number of landings specified as the "repeat visual inspection interval" in Table I of Lockheed Service Bulletin 093-57-218, Revision 1, dated September 9, 1996. Or

(2) Modify the left and right wing rear spars in accordance with the Accomplishment Instructions of Lockheed Service Bulletin 093-57-215, dated April 11, 1996. Within the thresholds specified in Table I of Lockheed Service Bulletin 093-57-218, Revision 1, dated September 9, 1996 (calculated from the date of installation of Lockheed Service Bulletin 093-57-215, dated April 11, 1996), perform the visual inspection required by paragraph (a) of this AD. Thereafter, repeat that inspection at intervals not to exceed the number of landings specified as the "repeat visual inspection interval" in Table I of Lockheed Service Bulletin 093-57-218, Revision 1, dated September 9, 1996.

NOTE 2: Accomplishment of the modification of the upper and lower caps of the rear spar between IWS 228 and IWS 346, in accordance with the Accomplishment Instructions of Lockheed Service Bulletin 093-57-203, dated July 25, 1988, Revision 1, dated August 11, 1989, or Revision 2, dated January 25, 1991, is considered acceptable for compliance with the modification specified in paragraph (e)(1) of this amendment.

(f) For Model L-1011-385-1 series airplanes: Accomplishment of the modification specified in paragraph (f)(1) or (f)(2) of this AD, within 12 months after the effective date of this AD, constitutes an acceptable alternative to the modification specified in paragraph (d) of this AD.

(1) Modify the inboard and outboard rear spars in accordance with the Accomplishment Instructions of Lockheed Service Bulletin 093-57-184, Revision 6, dated October 28, 1991; or Revision 7, dated December 6, 1994. Within the thresholds specified in Table Iof Lockheed Service Bulletin 093-57-218, Revision 1, dated September 9, 1996 (calculated from the date of installation of Lockheed Service Bulletin 093-57-184, Revision 6, dated October 28, 1991, or Revision 7, dated December 6, 1994), perform the visual inspection required by paragraph (a) of this AD. Thereafter, repeat that inspection at intervals not to exceed the number of landings specified as the "repeat visual inspection interval" in Table I of Lockheed Service Bulletin 093-57-218, Revision 1, dated September 9, 1996. Or

(2) Modify the inboard and outboard rear spars in accordance with the Accomplishment Instructions of Lockheed Service Bulletin 093-57-196, Revision 5, dated October 28, 1991; or Revision 6, dated December 6, 1994. Within the thresholds specified in Table I of Lockheed Service Bulletin 093-57-218, Revision 1, dated September 9, 1996 (calculated from the date of installation of Lockheed Service Bulletin 093-57-196, Revision 5, dated October 28, 1991, or Revision 6, dated December 6, 1994), perform the visual inspection required by paragraph (a) of this AD. Thereafter, repeat that inspection at intervals not to exceed the number of landings specified as the "repeat visual inspection interval" in Table I of Lockheed Service Bulletin 093-57-218, Revision 1, dated September 9, 1996.

NOTE 3: Accomplishment of the modification of the inboard and outboard rear spars, in accordance with the Accomplishment Instructions of Lockheed Service Bulletin 093-57-184, Revision 2, dated October 12, 1988; Revision 3, dated August 11, 1989, Revision 4, dated May 16, 1990; or Revision 5, dated May 23, 1990, is considered acceptable for compliance with the modification specified in paragraph (f)(1) of this amendment.

NOTE 4: Accomplishment of the modification of the inboard and outboard rear spars, in accordance with the Accomplishment Instructions of Lockheed Service Bulletin 093-57-196, Revision 1, dated October 25, 1988; Revision 2, dated July 31, 1989; Revision 3, dated March 7, 1990; or Revision 4, dated July 1, 1991, is considered acceptable for compliance with the modification specified in paragraph (f)(2) of this amendment.

(g) If any condition (i.e., number of discrepant fasteners per stiffener bay, or cracking) is identified during the accomplishment of the modification specified in Lockheed Service Bulletin 093-57-218, Revision 1, dated September 9, 1996, and that condition exceeds the limits specified in paragraph B.(3) of Part II of the Accomplishment Instructions of the service bulletin, prior to further flight, repair in accordance with a method approved by the Manager, Atlanta Aircraft Certification Office (ACO), FAA, Small Airplane Directorate.

Alternative Method of Compliance
(h) (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 anappropriate 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 96-12-24, amendment 39-9667, are approved as alternative methods of compliance with paragraph (d) of this AD.

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

Special Flight Permits
(i) 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.

Incorporation by Reference
(j) Except as provided by paragraph (g) of this AD, the actions shall be done in accordance with the following service bulletins, as applicable:

Lockheed Service Bulletin 093-57-184, Revision 6, dated October 28, 1991;or Lockheed Service Bulletin 093-57-184, Revision 7, dated December 6, 1994;

Lockheed Service Bulletin 093-57-196, Revision 5, dated October 28, 1991; or Lockheed Service Bulletin 093-57-196, Revision 6, dated December 6, 1994;

Lockheed Service Bulletin 093-57-203, Revision 3, dated October 28, 1991; or Lockheed Service Bulletin 093-57-203, Revision 4, dated March 27, 1995;

Lockheed Service Bulletin 093-57-215, dated April 11, 1996; and

Lockheed Service Bulletin 093-57-218, dated April 11, 1996; or Lockheed Service Bulletin 093-57-218, Revision 1, dated September 9, 1996.

Revision 1 of Lockheed Service Bulletin 093-57-218 contains the following list of effective pages:

Page Number
Revision Level
Shown on Page

Date Shown on Page
1, 2, 4-9, 13-18
1
September 9, 1996
3, 10-12, 19
Original
April 11, 1996

(1) The incorporation by reference of Lockheed Service Bulletin 093-57-218, dated April 11, 1996, was approved previously by theDirector of the Federal Register as of June 27, 1996 (61 FR 29642, June 12, 1996).

(2) The incorporation by reference of the remainder of the service bulletins listed above is approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51.

(3) Copies may be obtained from Lockheed Martin Aircraft & Logistics Center, 120 Orion Street, Greenville, South Carolina 29605. 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, One Crown Center, 1895 Phoenix Boulevard, Suite 450, Atlanta, Georgia; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

(k) This amendment becomes effective on July 28, 1999.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by superseding AD 96-12-24, amendment 39-9667 (61 FR 29642, June 12, 1996), which is applicable to all Lockheed Model L-1011-385 series airplanes, was published in the Federal Register on November 25, 1997 (62 FR 62728). The action proposed to continue to require inspections to detect cracking and other discrepancies of certain web-to-cap fasteners of the rear spar between inner wing stations 310 and 343, and of the web area around those fasteners; and various follow-on actions. That action also proposed to require accomplishment of a previously optional modification.

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

Support for the Proposal
One commenter supports the proposed rule.

Request to Clarify the Inspection Requirements
One commenter requests clarification of the subsequent inspections required by the proposed AD. The commenter states that the proposed AD does not clearly address the subsequent inspection program for Model L-1011-385-3 series airplanes that have accomplished the rear spar modification for extensive cracking "after June 27, 1996," because paragraph (a)(2) of the proposed AD only addresses spar replacements accomplished "prior to June 27, 1996."

The FAA points out that the inspection thresholds in Table I of Lockheed Service Bulletin 093-57-218, Revision 1, dated September 9, 1996 (which is referenced in the final rule as the appropriate source of service information), are calculated from the date of accomplishment of Lockheed Service Bulletin 093-57-215, dated April 11, 1996. In addition, the FAA considers that paragraph (e)(2) of the final rule adequately addresses the inspection requirements for operators that have accomplished the modification in accordance with Service Bulletin 093-57-215. No change has been made to paragraph (a)(2) of the final rule.

Request for Additional Inspections and a Reduced Inspection Threshold
One commenter requests revising the proposed AD to include additional inspections for detecting cracks that originate in the fastener holes, and to shorten the inspection thresholds after accomplishment of the cold working modification. The commenter adds that it recommends accomplishment of the modification as required by the proposed AD; however, the commenter does not consider that the modification should be used for complete reliance for crack prevention. Following accomplishment of the modification, the commenter recommends that certain other inspections of the wing rear spar web and upper cap be added to the inspection requirements of the proposed AD. The commenter suggests adding surface scan inspections using high frequency eddy current techniques, and ring probe inspections using low frequency eddy current techniques. The commenter alsorecommends that, instead of accomplishing the inspections at 5,000 landings, the inspections be accomplished at 500 flight cycles following the cold working modification.

The commenter states that its recommendations are based on its service experience and a damage tolerance assessment (DTA). The commenter also states that, after modifying its entire fleet of Model L-1011-385-3 series airplanes in accordance with paragraph (d) of the proposed AD, subsequent cracking was found before 5,000 landings. The commenter adds that its service experience indicates that new or recurring cracks occur within 500 to 1,000 flight cycles after repair of the upper spar cap. In addition, half-crack lengths of approximately 0.25 inch were found during subsequent inspections, and a DTA of the area indicates that inspections at 500 flight cycles are required to ensure aircraft safety, regardless of the cold working condition.

The FAA does not concur that additional inspections should be included in the final rule, or that the inspection threshold of 5,000 landings, as required by paragraphs (d) and (e)(1) of the proposed AD, should be reduced to 500 landings. The FAA considers it is likely that other factors induced the early cracking found in the operator's airplane, and that the 5,000-flight-cycle threshold required by the proposed AD is an adequate inspection threshold after accomplishment of the fastener hole cold working. The FAA points out that it will continue to monitor service findings of modified airplanes and may revise the inspection requirements in the future, if necessary. However, no changes were made to the inspection thresholds required by paragraph (d) or (e)(1) of the final rule.

Explanation of Changes Made to This Final Rule
The notice of proposed rulemaking (NPRM) references Lockheed Service Bulletin 093-57-212, dated November 14, 1994, as amended by Change Notification CN1, dated September 27, 1995, as an appropriate source of service information for accomplishment of the modifications specified in paragraphs (f)(1) and (f)(2) of the NPRM. The FAA finds that the procedures in Service Bulletin 093-57-212 are no longer necessary because the procedures included in the other service bulletins cited in those paragraphs are adequate for accomplishment of the actions required by this AD. The references to that service bulletin have been removed from the final rule.

Although the NPRM includes references to certain Change Notifications for a number of service bulletins, the FAA has determined that it is unnecessary to include those references in the final rule. The FAA points out that the Change Notifications did not include any substantive changes to the service bulletins, and that such change notifications included only minor editorial changes or clarification of certain data. The FAA has determined that the service bulletins referenced in the final rule include all of the procedures necessary for accomplishment of the actions required by this AD. In light of this, references to the Change Notifications were deleted from the final rule.

Although the NPRM did not include references to certain earlier revision levels of Lockheed Service Bulletins 093-57-184, 093-57-196, and 093-57-203, the FAA has determined that references to those earlier revision levels should be included in the final rule to give credit to any operator that may have accomplished the modification previously in accordance with those service bulletins. In light of this, the FAA has included references to those earlier service bulletins in NOTE 2, NOTE 3, and NOTE 4 of this AD. The FAA considers that the service bulletins referenced in those notes are adequate for specifying the procedures necessary for accomplishment of the actions required by this AD.

The FAA has added Lockheed Service Bulletin 093-57-203, Revision 4, dated March 27, 1995, to paragraph (e)(1) of this AD as an additional reference for the accomplishment ofthe rear spar modification.

In paragraph (g) of this AD, the FAA has added the word "discrepant" preceding the word "fasteners" in the parenthetical phrase. This word was added to clarify that one of the conditions to be identified during the required modification is for "discrepant fasteners" rather than just "fasteners."

Conclusion
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 neither increase the economic burden on any operator nor increase the scope of the AD.

Cost Impact
There are approximately 235 Lockheed Model L-1011-385 series airplanes of the affected design in the worldwide fleet. The FAA estimates that 117 airplanes of U.S. registry will be affected by this AD.

The actions that are currently required by AD 96-12-24, and retained in this AD, take approximately 13 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the currently required actions on U.S. operators is estimated to be $91,260, or $780 per airplane.

The actions that are required by this new AD will take approximately 100 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the new requirements of this AD on U.S. operators is estimated to be $702,000, or $6,000 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.

Regulatory Impact
The regulations adopted herein will not have substantial direct effects on the States, on the relationship between the national government and the States, or onthe 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 U.S.C. 106(g), 40113, 44701.

39.13 [Amended]
2. Section 39.13 is amended by removing amendment 39-9667 (61 FR 29642, June 12, 1996), and by adding a new airworthiness directive (AD), amendment 39-11202, to read as follows: