AD 2000-10-20

This amendment adopts a new airworthiness directive (AD), applicable to all Lockheed Model L-1011-385 series airplanes, that requires repetitive inspections to detect cracking of the fuselage skin in the areas of the left- and right-hand stringerless sidewall window belts, and repair, if necessary. This amendment is prompted by reports of fatigue cracks found in the fuselage skin where the skin thickness steps from 0.40 to 0.23 inch. The actions specified by this AD are intended to detect and correct cracking of the fuselage skin, which could result in reduced structural integrity of the airplane.

Final Rule

2000-10-20 LOCKHEED: Amendment 39-11744. Docket 98-NM-311-AD.

Applicability: All Model L-1011-385 series airplanes, as listed in Lockheed Service Bulletin 093-53-279, dated May 6, 1998; 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 (f) 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 detect and correct cracking of the fuselage skin, which could result in reduced structural integrity of the airplane, accomplish the following:

(a) Perform an ultrasonic inspection on the fuselage skin in the area of the stringerless sidewall window belts, at the radii on both the forward and aft sides of the machined cutout where the fuselage skin steps from 0.40 to 0.23 inch, to detect cracking in the base of the radii. Accomplish the inspection in accordance with Lockheed Service Bulletin 093-53-279, dated May 6, 1998, at each of the 6 specific inspection zones identified in the service bulletin at the later of the times specified in paragraphs (a)(1) and (a)(2) of this AD.

(1) Prior to the accumulation of 20,000 total flight cycles; or

(2) Within 600 flight cycles or 6 months after the effective date of this AD, whichever occurs first.

(b) For readings of less than 20 percent obtained at all 6 inspection zones during the ultrasonic inspection required by paragraph (a) of this AD: Repeat the ultrasonic inspection thereafter at intervals not to exceed 1,500 flight cycles.

(c) Except as provided by paragraph (e) of this AD: For any reading of 20 percent or greater and less than or equal to 50 percent obtained at any inspection zone during the ultrasonic inspection required by paragraph (a) of this AD, prior to further flight, perform a low frequency eddy current (LFEC) inspection to measure the depth of the cracking, in accordance with Lockheed Service Bulletin 093-53-279, dated May 6, 1998.

(1) If the results of the LFEC inspection are outside the reject zone, as defined in the service bulletin: Within 1,500 flight cycles, repeat both the ultrasonic and LFEC inspections specified by paragraphs (a) and (c), respectively, of this AD.

(i) If the results of the LFEC inspection specified by paragraph (c)(1) of this AD are outside the reject zone: Within 1,800 flight cycles afterthe initial crack finding, as detected during the ultrasonic inspection specified in paragraph (a) of this AD, repair any affected inspection zone in accordance with Part II of the Accomplishment Instructions of the service bulletin. Such repair constitutes terminating action for the repetitive inspection requirements of this AD for the repaired inspection zone only.

(ii) If the results of the LFEC inspection specified by paragraph (c)(1) of this AD are within the reject zone: Prior to further flight, repair any affected inspection zone in accordance with Part II of the Accomplishment Instructions of the service bulletin. Such repair constitutes terminating action for the repetitive inspection requirements of this AD for the repaired inspection zone only.

(2) If the results of the LFEC inspection are within the reject zone, as defined in the service bulletin: Prior to further flight, repair any affected inspection zone in accordance with Part II of the AccomplishmentInstructions of the service bulletin. Such repair constitutes terminating action for the repetitive inspection requirements of this AD for the repaired inspection zone only.

(d) Except as provided by paragraph (e) of this AD: For any reading of 50 percent or greater obtained at any inspection zone during the ultrasonic inspection required by paragraph (a) of this AD, prior to further flight, perform a LFEC inspection to measure the depth of the cracking, in accordance with Lockheed Service Bulletin 093-53-279, dated May 6, 1998.

(1) If the results of the LFEC inspection are outside the reject zone, as defined in the service bulletin: Within 300 flight cycles, repeat both the ultrasonic and LFEC inspections specified in paragraphs (a) and (c), respectively, of this AD.

(i) If the results of the LFEC inspection specified by paragraph (d)(1) of this AD are outside the reject zone: Within 600 flight cycles after the initial crack finding, as detected during the ultrasonic inspection specified in paragraph (a) of this AD, repair any affected inspection zone in accordance with Part II of the Accomplishment Instructions of the service bulletin. Such repair constitutes terminating action for the repetitive inspection requirements of this AD for the repaired inspection zone only.

(ii) If the results of the LFEC inspection specified by paragraph (d)(1) of this AD are within the reject zone: Prior to further flight, repair any affected inspection zone in accordance with Part II of the Accomplishment Instructions of the service bulletin. Such repair constitutes terminating action for the repetitive inspection requirements of this AD for the repaired inspection zone only.

(2) If the results from the LFEC inspection are within the reject zone, as defined in the service bulletin: Prior to further flight, repair any affected inspection zone in accordance with Part II of the Accomplishment Instructions of the service bulletin. Such repair constitutes terminating action for the repetitive inspection requirements of this AD for the repaired inspection zone only.

(e) For any inspection results that require repair in two adjacent zones: Prior to further flight, repair in accordance with a method approved by the Manager, Atlanta Aircraft Certification Office (ACO), FAA, Small Airplane Directorate. Alternative Methods of Compliance

(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 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.

Special Flight Permits

(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.

Incorporation by Reference

(h) Except as provided by paragraph (e) of this AD, the actions shall be done in accordance with Lockheed Service Bulletin 093-53-279, dated May 6, 1998. 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 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.(i) This amendment becomes effective on July 12, 2000.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to all Lockheed Model L-1011-385 series airplanes was published in the Federal Register on February 16, 2000 (65 FR 7801). That action proposed to require require repetitive inspections to detect cracking of the fuselage skin in the areas of the left- and right-hand stringerless sidewall window belts, and repair, if necessary.

Comments

Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were submitted in response to the proposal or the FAA's determination of the cost to the public.

Conclusion

The FAA has determined that air safety and the public interest require the adoption of the rule as proposed.

Cost Impact

There are approximately 235 airplanes of the affected design in the worldwide fleet. The FAA estimates that 117 airplanes ofU.S. registry will be affected by this AD, that it will take approximately 48 work hours per airplane to accomplish the required inspection, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $336,960, or $2,880 per airplane.

The cost impact figure discussed above is 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 a substantial direct effect 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, it is determined that this final rule does not have federalism implications under Executive Order 13132.

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 part39 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: