AD 96-12-24

This amendment adopts a new airworthiness directive (AD) that is applicable to all Lockheed Model L-1011-385 series airplanes. This action requires inspections to detect cracking and other discrepancies of certain web-to-cap fasteners of the rear spar between inner wing stations (IWS) 310 and 343, and of the web area around those fasteners; and various follow-on actions. This AD also provides for an optional modification which, if accomplished, will defer the initiation of the inspections for a certain period of time. This amendment is prompted by a report of fatigue cracking in the web of the rear spar of the wing. The actions specified in this AD are intended to prevent such fatigue cracking, which could result in failure of the rear spar of the wing and consequent fuel spillage.

Final rule; request for comments.

96-12-24 LOCKHEED: Amendment 39-9667. Docket 96-NM-104-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 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 request approval for an alternative method of compliance in accordance with paragraph (e) 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.

To prevent fatiguecracking 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:

(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; 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 within 10 days after the effective date of this AD, whichever occurs later.

(2) For airplanes on which the wing rear spar has been modified prior to the effective date of this AD 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, 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 the effective date of this AD, 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.

(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 (ECSS) inspections, or bolt hole eddy current (BHEC) inspections, as appropriate, to confirm cracking, in accordance with Lockheed Service Bulletin 093-57-218, dated April 11, 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 1 of the service bulletin.

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

(d) Accomplishment of the modification specified in Part II of the Accomplishment Instructions of Lockheed Service Bulletin 093-57-218, dated April 11, 1996, and in accordance with that service bulletin, allows the visual inspections required by paragraph (a) of this AD to be deferred for the period specified in paragraph (d)(2) of this AD.

(1) If any condition (i.e., number of fasteners per stiffener bay, or cracking) is identified during the accomplishment of the modification that exceeds the limits specified in paragraph B.3. of Part II of the Accomplishment Instructions of the service bulletin, prior to further flight, repairin accordance with a method approved by the Manager, Atlanta Aircraft Certification Office (ACO), FAA, Small Airplane Directorate.

(2) 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 the service bulletin.

(e) 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, 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.

(f) 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.

(g) The actions shall be done in accordance with Lockheed L-1011 Service Bulletin 093-57-218, dated April 11, 1996. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. 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, Atlanta Aircraft Certification Office, Small Airplane Directorate, 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.

(h) This amendment becomes effective on June 27, 1996.

The FAA received a report indicating that fatigue cracking was found on the web of the rear spar of the wing on a Lockheed Model L-1011-385 series airplane that had accumulated approximately 18,900 total landings. The crack, which was 24 inches long, grew rapidly in a downward direction at a 45-degree angle and stopped behind the trunnion fitting of the main landing gear. Consequently, the airplane began leaking fuel during final taxi.

Fatigue cracking in the web of the rear spar of the wing can originate in the fasteners common to the web and the vertical leg of the upper cap. Such cracking can grow and remain undetected for a significant period of time because the crack can propagate on the interior (fuel side) of the web before it breaches the aft side (flap side) of the web. Such fatigue cracking, if not detected and corrected in a timely manner, could result in failure of the rear spar of the wing and consequent fuel spillage. Other Relevant Rules

The FAA previously issued AD 96-07-13, amendment 39-9563 (61 FR 16379, April 15, 1996), which requires various X-ray, eddy current, and ultrasonic inspections to detect fatigue cracking of certain areas of the rear spar caps, web, skin, and certain fastener holes; and repair or modification, if necessary. The inspections are required to be repeated at intervals of 2,000 flight cycles. 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.

The fatigue cracking that was the subject of the recent in-service incident, described above, indicates that fatigue cracking in the area of the web of the rear spar of the wing apparently can occur and propagate at a faster rate and at a reduced threshold than previously realized. In light of this, the FAA is considering revising AD 96-07-13 to reduce the repetitive inspection intervals to ensure that fatigue cracking can be found in a more timely manner. (The FAA indicated this in the preamble to that AD.) Explanation of Relevant Service Information

The FAA has reviewed and approved Lockheed L-1011 Service Bulletin 093-57-218, dated April 11, 1996. Part I of the service bulletin describes procedures for repetitive visual inspections to detect fatigue cracking and other discrepancies (i.e., corrosion, fastener looseness, nicks, scratches, or other surface damage) of certain web-to-cap fasteners of the rear spar between inner wing stations (IWS) 310 and 343, and of the web area around those fasteners; and various follow-on actions. The follow-on actions include repetitive visual inspections, eddy current surface scan (ECSS) inspections, bolt hole eddy current (BHEC) inspections, and repair.

Part II of the service bulletin describes procedures for an optional modification that will allow the initiation of the visual inspections to be deferred for a period of time. The modification involves removing certain web-to-cap fasteners, verifying that the subject fastener holes are free of cracks, cold working the fastener holes, and replacing the fasteners with oversize fasteners. Explanation of the Requirements of the Rule

Since an unsafe condition has been identified that is likely to exist or develop on other Model L-1011-385 series airplanes of the same type design, this AD is being issued 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. This AD requires repetitive visual inspections to detect cracking and other discrepancies of certain web-to-cap fasteners of the rear spar between IWS 310 and IWS 343, and of the web area around those fasteners; and various follow-on actions. This AD also provides for an optional modification which, if accomplished, will allow the initiation of the visual inspections to be deferred for a certain period of time. The actions are required to be accomplished in accordance with the Lockheed service bulletin described previously.

The inspections that are required by this AD are in addition to -- not in lieu of -- those currently required by AD 96-07-13, amendment 39-9563. Differences between the Rule and the Referenced Service Information

Operators should note that, although the Lockheed service bulletin specifies that the manufacturer must be contacted for disposition of certain conditions, this AD requires that the repair of those conditions be accomplished in accordance with a method approved by the Manager, Atlanta Aircraft Certification Office (ACO), FAA, Small Airplane Directorate. Determination of Rule's Effective Date

Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon areimpracticable, and that good cause exists for making this amendment effective in less than 30 days. 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 96-NM-104-AD." The postcard will be date stamped and returned to the commenter. 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 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, Aviationsafety, 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 adding the following new airworthiness directive: