Airworthiness directives: Lockheed,

[Federal Register: August 19, 1998 (Volume 63, Number 160)]

[Proposed Rules]

[Page 44411-44413]

From the Federal Register Online via GPO Access [wais.access.gpo.gov]

[DOCID:fr19au98-25]

Proposed Rules Federal Register

This section of the FEDERAL REGISTER contains notices to the public of the proposed issuance of rules and regulations. The purpose of these notices is to give interested persons an opportunity to participate in the rule making prior to the adoption of the final rules.

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-NM-199-AD]

RIN 2120-AA64

Airworthiness Directives; Lockheed Model L-1011-385 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

SUMMARY: This document proposes the supersedure of an existing airworthiness directive (AD), applicable to all Lockheed Model L-1011- 385 series airplanes, that currently requires inspections to detect cracking of fuselage station (FS) 983 main frame (left and right sides), and repair, if necessary. That AD was prompted by reports of cracks found in the left and right sides of the FS 983 main frame, below the level of the cabin floor. This action would add a new requirement to review the airplane maintenance records to determine if a crack within the FS 983 main frame web was detected previously, and if repair of any such crack was deferred; and repair, prior to further flight, if necessary. The actions specified by the proposed AD are intended to prevent cracking of the FS 983 frame, which could result in reduced structural integrity of the fuselage.

DATES: Comments must be received by October 5, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 98-NM-199-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal holidays.

The service information referenced in the proposed rule may be obtained from Lockheed Aeronautical Systems Support Company (LASSC), Field Support Department, Dept. 693, Zone 0755, 2251 Lake Park Drive, Smyrna, Georgia 30080. This information may be examined 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.

FOR FURTHER INFORMATION CONTACT: Thomas Peters, Aerospace Engineer, Systems and Flight Test Branch, ACE-116A, FAA, Small Airplane Directorate, Atlanta Aircraft Certification Office, One Crown Center, 1895 Phoenix Boulevard, suite 450, Atlanta, Georgia 30349; telephone (770) 703-6063; fax (770) 703-6097.

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to participate in the making of the proposed 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 above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this notice may be changed in light of the comments received.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed 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 summarizing each FAA-public contact concerned with the substance of this proposal will be filedin the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this notice must submit a self-addressed, stamped postcard on which the following statement is made: ``Comments to Docket Number 98-NM-199-AD.'' The postcard will be date stamped and returned to the commenter.

Availability of NPRMs

Any person may obtain a copy of this NPRM by submitting a request to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 98-NM-199-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

On November 5, 1991, the FAA issued AD 91-21-51, amendment 39-8099 (56 FR 61361, December 3, 1991), applicable to all Lockheed Model L- 1011-385 series airplanes, to require inspections to detect stress corrosion cracking of fuselage station (FS) 983 main frame (left and right sides), and repair, if necessary. That action was prompted by reports of cracks found in the left and right sides of FS 983 main frame, below the level of the cabin floor. The requirements of that AD are intended to prevent cracks in the fuselage frame, which, if not corrected, could result in reduced structural integrity of the fuselage.

That AD also contained a provision that, if a single crack was detected that was completely contained within a certain area of the FS 983 main frame web, repair of the crack was not required. In lieu of repair, the cracked area could be treated with corrosion inhibitor and inspected repetitively using internal visual and eddy current techniques. In the preamble to AD 91-21-51, the FAA indicated that these repetitive inspections were considered ``interim action'' and that further rulemaking action was being considered. The FAA now has determined that further rulemaking action is indeed necessary. As a follow-on action from that determination, the FAA is now proposing to mandate repair of any crack for which repair was deferred. Such repair would constitute terminating action for the repetitive inspection requirement.

Explanation of Relevant Service Information

The FAA has reviewed and approved Lockheed Tristar L-1011 Service Bulletin 093-53-266, dated March 2, 1992, as revised by Change Notification CN1, dated July 10, 1992; which describes, among other things, procedures for repairing cracking of the FS 983 main frame web. The service bulletin specifies that repair of any such cracking may be accomplished in

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accordance with Lockheed Drawing LCC-7622-327 (for Lockheed Model L- 1011-385 series airplanes having serial numbers 1002 through 1012 inclusive), or LCC-7622-325 (for Lockheed Model L-1011-385 series airplanes having serial numbers 1013 through 1250 inclusive); or partial frame replacement may be accomplished in accordance with Lockheed Drawing LCC-7622-326 (for all Lockheed Model L-1011-385 series airplanes).

Explanation of Requirements of Proposed Rule

Since an unsafe condition has been identified that is likely to exist or develop on other products of this same type design, the proposed AD would supersede AD 91-21-51 to continue to require inspections to detect cracking of the FS 983 main frame (left and right sides), and repair, if necessary. The proposed AD adds a requirement to review the airplane maintenance records to determine if a crack within the FS 983 main frame web was detected previously, and if repair of any such crack was deferred; and repair, if necessary. Accomplishment of such repair would constitute terminating action for the repetitive inspection requirements of this proposed AD. The actions would be required to be accomplished in accordance with the service bulletin described previously, except as discussed below.

Differences Between Proposed Rule and Service Bulletin

Operators should note that, unlike the procedures described in Lockheed Tristar L-1011 Service Bulletin 093-53-266, as revised by Change Notification CN1, this proposed AD would not permit long-term repetitive inspections of main frame web areas with only a single crack to continue in lieu of accomplishment of a repair. The FAA has determined that long-term continued operational safety will be better assured by modifications or repairs to remove the source of the problem, rather than by repetitive inspections. Long-term inspections may not be providing the degree of safety assurance necessary for the transport airplane fleet. This, coupled with a better understanding of the human factors associated with numerous repetitive inspections, has led the FAA to consider placing less emphasis on special procedures and more emphasis on modifications. The proposed repair requirement is in consonance with these considerations.

Cost Impact

There are approximately 235 airplanes of the affected design in the worldwide fleet. The FAA estimates that 117 airplanes of U.S. registry would be affected by this proposed AD.

The external eddy current inspection that currently is required by AD 91-21-51, and that would be retained in this AD, takes approximately 1 work hour per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of this inspection on U.S. operators is estimated to be $7,020, or $60 per airplane.

The internal visual and eddy current inspection that currently is required by AD 91-21-51, and that would be retained in this AD, takes approximately 1 work hour per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of this inspection on U.S. operators is estimated to be $7,020, or $60 per airplane, per inspection cycle.

The cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the current or proposed requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted.

Should an operator be required to accomplish the repair of cracking that is proposed in this AD, it would take approximately 30 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 repair proposed by this AD on U.S. operators is estimated to be $210,600, or $1,800 per airplane.

Regulatory Impact

The regulations proposed herein would 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 proposal would not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

For the reasons discussed above, I certify that this proposed regulation (1) is not a ``significant regulatory action'' under Executive Order 12866; (2) is not a ``significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) if promulgated, 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 copy of the draft regulatory evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting the Rules Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend 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.

   Sec. 39.13 [Amended]

2. Section 39.13 is amended by removing amendment 39-8099 (56 FR 61361, December 3, 1991), and by adding a new airworthiness directive (AD), to read as follows:

   Lockheed: Docket 98-NM-199-AD. Supersedes AD 91-21-51, amendment 39- 8099.

   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 (g)(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 accomplished previously.

   To prevent cracking in the fuselage station (FS) 983 frame, which could result in reduced structural integrity of the fuselage, accomplish the following:

   Restatement of Requirements of AD 91-21-51, Amendment 39-8099

   (a) Within 20 days after December 18, 1991 (the effective date of AD 91-21-51, amendment 39-8099), inspect the left and right sides of FS 983 main frame from waterline (WL) 175 to WL 200 to detect cracks using a high frequency eddy current procedure, in accordance with paragraph A. of the Accomplishment Instructions of

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   Lockheed Service Bulletin 093-53-264, dated October 4, 1991. At the operator's option, the internal inspection required by paragraph (d) below may be used in lieu of the external inspection.

   (b) If cracks that extend into the main frame caps are found during the inspection performed in accordance with paragraph (a) of this AD, prior to further flight, repair in accordance with a method approved by the Manager, Atlanta Aircraft Certification Office (ACO), FAA, Small Airplane Directorate.

   (c) Within 60 days after December 18, 1991, perform an internal visual and eddy current inspection of the FS 983 main frame cap and web in accordance with paragraph B. of the Accomplishment Instructions of Lockheed Service Bulletin 093-53-264, dated October 4, 1991.

   (d) If cracks in the following locations are found during the inspection required by paragraph (c) of this AD, prior to further flight, repair in accordance with a method approved by the Manager, Atlanta ACO.

   (1) Any crack extending into the main frame caps.

   (2) Any crack extending into the web-to-cap radius.

   (3) Any crack extending into a web area outside the shaded area shown in Figure 1, Sheet 3, of Lockheed Service Bulletin 093-53-264, dated October 4, 1991.

   (4) More than 1 crack within the main frame web area shown in Figure 1, Sheet 3, of Lockheed Service Bulletin 093-53-264, dated October 4, 1991.

   (e) If, during the inspection required by paragraph (c) of this AD, a single crack is found that is completely contained within the main frame web area shown in Figure 1, Sheet 3, of Lockheed Service Bulletin 093-53-264, dated October 4, 1991: Prior to further flight, treat the cracked section of the web with corrosion inhibitor in accordance with the service bulletin. Thereafter, repeat the inspections at intervals not to exceed 90 days, using the internal inspection procedure required by paragraph (c) of this AD.

   New Requirements of This AD

   (f) Within 18 months after the effective date of this AD, review the airplane maintenance records to determine if a crack within the main frame web area has been detected previously, and if repair of any such crack was deferred in accordance with paragraph (e) of AD 91-21-51, amendment 39-8099. For any crack for which repair has been deferred, prior to further flight, repair the crack in accordance with Lockheed Tristar L-1011 Service Bulletin 093-53-266, dated March 2, 1992; as revised by Change Notification CN1, dated July 10, 1992. Accomplishment of such repair constitutes terminating action for the repetitive inspections required by paragraph (e) of this AD.

   Note 2: Lockheed Tristar L-1011 Service Bulletin 093-53-266, dated March 2, 1992; as revised by Change Notification CN1, dated July 10, 1992; references Lockheed Drawings LCC-7622-325, LCC-7622- 326, and LCC-7622-327, as additional sources of service information to accomplish repairs.

   (g)(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 an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Atlanta ACO.

   (g)(2) Alternative methods of compliance, approved previously in accordance with AD 91-21-51, amendment 39-8099, are approved as alternative methods of compliance with the inspection requirements of paragraphs (a) and (c) of this AD, and the repair/modification requirements of paragraphs (b) and (d) of this AD.

   Note 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Atlanta ACO.

   (h) 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.

   Issued in Renton, Washington, on August 12, 1998. John J. Hickey, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

   [FR Doc. 98-22241Filed8-18-98; 8:45 am]

   BILLING CODE 4910-13-U