AD 95-21-07

This amendment adopts a new airworthiness directive (AD), applicable to Lockheed Model L-1011-385 series airplanes, that requires modifications of various fluid drainage areas of the fuselage. This amendment is prompted by incidents involving corrosion and fatigue cracking in transport category airplanes that are approaching or have exceeded their economic design goal; these incidents have jeopardized the airworthiness of the affected airplanes. The actions specified by this AD are intended to prevent degradation of the structural capabilities of the affected airplanes due to problems associated with corrosion.

Final Rule

95-21-07 LOCKHEED: Amendment 39-9392. Docket 94-NM-254-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 use the authority provided in paragraph (b) 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.

To prevent structural failure due to the problems associated with corrosion accomplish the following:

(a) Accomplish the modifications, installations, and inspections described in the Lockheed service bulletins listed in Section 7.2 of Lockheed Document Number LR 31889, "Corrosion Prevention and Control Program, TriStar L-1011," Revision A, dated April 15, 1994 (hereafter referred to as "the Document"), in accordance with the following schedule:

NOTE 2: Airplanes on which the modifications, installations, and inspections required by this paragraph have been accomplished prior to the effective date of this AD or during production are considered to be in compliance with this paragraph.

NOTE 3: Airplanes on which the modifications, installations, and inspections required by this paragraph have been accomplished previously in accordance with an earlier version of the applicable service bulletin listed in Section 7.2 of the Document, are considered to be in compliance with this paragraph.

NOTE 4: In lieu of the installation of insulation batts standoffs (stud-type) specified in Lockheed Service Bulletin 093-53-095, Revision 2, dated June 22, 1987, operators may install any of the optional insulation batts standoffs specified in Appendix D of the Document. Such installation is considered to be in compliance with these requirements of this AD.

NOTE 5: "Airplane zones," "implementation ages," and "repeat intervals," as referred to in this paragraph, are specified in Section 4.3 of the Document.

(1) For modifications, installations, and inspections located in an airplane zone that has not yet exceeded the "implementation age" (IA) for that zone as of December 17, 1994 (one year after the effective date of AD 93-20-03, amendment 39-8710): Compliance is required no later than the IA plusthe repeat (R) interval for the applicable zone.

(2) For modifications, installations, and inspections located in an airplane zone that has exceeded the IA for that zone as of December 17, 1994: Compliance is required within one R interval for that zone, measured from December 17, 1994.

(3) For airplanes that are 20 years old or older as of December 17, 1994: Accomplishment of the modifications, installation, and inspections is required within one R interval for the applicable airplane zone, but not to exceed 6 years, measured from December 17, 1994, whichever occurs first.

(b) 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 Aircraft Certification Office (ACO), ACE-115A, FAA, Small Airplane Directorate. 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 6: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Atlanta ACO.

(c) 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.

(d) The actions shall be done in accordance with Lockheed Document Number LR 31889, "Corrosion Prevention and Control Program, TriStar L-1011," Revision A, dated April 15, 1994, which contains the following list of effective pages:

Page Number
Revision Level
Shown on Page
Date
Shown on Page
0.1-0.4, 0.6, 1.1, 1.3, 2.1, 2.2, 3.1-3.4, 4.1-4.8, 4.12, 4.14, 4.15, 4.20, 4.24, 4.28, 4.30-4.33, 4.36-4.41, 5.2, 6.1, A.1, A.2, B.3, B.5-B.13, C.2-C.10
Original
March 15, 1991
0.5, 1.2, 4.9-4.11, 4.13, 4.16-4.19, 4.21-4.23, 4.25-4.27, 4.29, 4.34, 4.35, 5.1, 7.1-7.4,B.2, B.4, C.1, D.1
Revision A
April 15, 1994

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. 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.

(e) This amendment becomes effective on November 17, 1995.

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 Model L-1011-385 series airplanes was published in the Federal Register on February 22, 1995 (60 FR 9796). That action proposed to require the accomplishment of modifications, installations, and other actions relative to fluid drainage areas of the fuselage.

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

One commenter supports the proposal.

One commenter requests that the proposal be revised to remove the requirement to comply with the procedures described in Lockheed Service Bulletin 093-53-095, Revision 2, dated June 22, 1987. This specific service bulletin describes procedures for installing drainage provisions at the pressure deck of the nose landing gear. The commenter states thatthese procedures are listed as part of Corrosion Task C-53-110-05 in the Model L-1011 Corrosion Prevention and Control Program (Lockheed Document LR 31889), and are mandated by AD 93-20-03, amendment 39-8710 (58 FR 60775, November 18, 1993). The FAA does not concur. Corrosion Task C-53-110-05 entails an inspection for corrosion of the pressure deck area above the nose landing gear compartment. An additional part of that Task is the installation of an insulation standoff modification that is described in Appendix D of Lockheed Document LR 31889. However, the actions proposed in the notice, and described in Lockheed Service Bulletin 093-53-095, go beyond those currently mandated by AD 93-20-03. These new actions require the installation of two drain valves and the installation of additional drain holes. The FAA has determined that these actions must be accomplished in order to positively address the unsafe condition presented by the problems associated with corrosion.

This commenter also requests that the final rule be revised to allow the installation of any of the optional insulation standoffs specified in Appendix D ["Insulation Batts Standoffs (Bilges)"] of Lockheed Document LR 31889. The commenter points out that Lockheed Service Bulletin Service Bulletin 093-53-095 specifically calls for the installation of stud-type standoffs, but Appendix D of the Lockheed Document allows the use of several options for maintaining a space between structure and insulation. This particular commenter, a U.S. operator, elected to install (previously) the "egg crate" option, and requests that the AD indicate that use of such an option is considered to be in compliance with the intent of the rule. The FAA concurs. A new Note 4 has been added to the final rule to specify this.

Paragraph (a)(2) of the final rule has been revised to correct a typographical error that appeared in the published version of the notice. In the notice, the compliance terminology of that paragraph was stated as, ". . . that has exceeded the IA for that zone as December 17, 1994. . ." However, it should have read, ". . . as of December 17, 1994. . ." The final rule has been corrected accordingly.

Additionally, the final rule has been revised to clarify that the issuance date of Lockheed Document LR 31889 is April 15, 1994.

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.

There are approximately 241 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 proposed AD. It will take approximately 236 work hours per airplane to accomplish the required actions, including time to gain access and close up. The average labor rate is currently $60 per work hour. Based on these figures, the total cost impact of the requirements of this AD on U.S. operators is estimated to be $1,656,720, or $14,160 per airplane.

The total 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.

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), 40101, 40113, 44701.

39.13 - [Amended]
2. Section 39.13 is amended by adding the following new airworthiness directive: