[Federal Register Volume 62, Number 90 (Friday, May 9, 1997)]
[Proposed Rules]
[Pages 25565-25566]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-12252]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-NM-256-AD]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to all Lockheed Model L-1011-385 
series airplanes. This proposal would require repetitive external 
visual inspections and internal borescope inspections to detect 
discrepancies of the elevator assembly; and repair/modification of any 
discrepancy. This proposal is prompted by a report of fretting at the 
diagonal truss to web joint of the elevator and cracking in the cap 
fillet radius adjacent to the joint, apparently due to loose fasteners 
as a result of local vibration. The actions specified by the proposed 
AD are intended to detect and correct such fretting and cracking, which 
could result in reduced structural integrity of the elevator and 
consequent flutter instability if coupled with other structural 
failures.

DATES: Comments must be received by June 20, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 96-NM-256-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, Campus Building, 1701 Columbia Avenue, Suite 2-
160, College Park, Georgia.

FOR FURTHER INFORMATION CONTACT: Thomas Peters, Aerospace Engineer, 
Systems and Flight Test Branch, ACE-116A, FAA, Small Airplane 
Directorate, Atlanta Aircraft Certification Office, Campus Building, 
1701 Columbia Avenue, Suite 2-160, College Park, Georgia 30337-2748; 
telephone (404) 305-7367; fax (404) 305-7348.

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 filed in 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 96-NM-256-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-103, Attention: Rules 
Docket No. 96-NM-256-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received a report of fretting at the diagonal truss to 
web joint of the elevator and cracking in the cap fillet radius 
adjacent to the joint on a Lockheed Model L-1011-385 series airplane. 
The thickness of the truss was worn in half (i.e., worn from 0.040 to 
0.020 inches). The apparent cause of the fretting and cracking has been 
attributed to loose fasteners that attach the diagonal trusses with the 
elevator ribs, as a result of local vibration. Such fretting and 
cracking, if not detected and corrected, could result in reduced

[[Page 25566]]

structural integrity of the elevator and consequent flutter instability 
if coupled with other structural failures.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Lockheed Service Bulletin 093-55-
031, dated April 26, 1996, which describes procedures for repetitive 
external visual inspections and internal borescope inspections to 
detect discrepancies (i.e., loose/missing fasteners or rivets, 
sponginess, sheared rivets, fretting, damage, and cracking) of the 
elevator assembly; and repair/modification, if necessary.

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 require repetitive external visual inspections and 
internal borescope inspections to detect discrepancies (i.e., loose/
missing fasteners or rivets, sponginess, sheared rivets, fretting, 
damage, and cracking) of the elevator assembly; and repair/modification 
of any discrepancy. The actions would be required to be accomplished in 
accordance with the service bulletin described previously.

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 would be affected by this 
proposed AD, that it would take approximately 20 work hours per 
airplane to accomplish the proposed actions, and that the average labor 
rate is $60 per work hour. Based on these figures, the cost impact of 
the proposed AD on U.S. operators is estimated to be $140,400, or 
$1,200 per airplane.
    The cost impact figure discussed above is based on assumptions that 
no operator has yet accomplished any of the proposed 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 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 adding the following new 
airworthiness directive:

Lockheed: Docket 96-NM-256-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 
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 (c) 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 fretting at the diagonal truss to web 
joint of the elevator, and cracking in the cap fillet radius 
adjacent to the joint, which could result in reduced structural 
integrity of the elevator and consequent flutter instability if 
coupled with other structural failures, accomplish the following:
    (a) Within 12 months after the effective date of this AD, 
perform an external visual inspection and internal borescope 
inspection to detect discrepancies (i.e., loose/missing fasteners or 
rivets, sponginess, sheared rivets, fretting, damage, and cracking) 
of the elevator assembly, in accordance with Part I of the 
Accomplishment Instructions of Lockheed L-1011 Service Bulletin 093-
55-031, dated April 26, 1996. Repeat the inspections thereafter at 
intervals not to exceed 18 months.
    (b) If any discrepancy is detected during any inspection 
required by this AD, prior to further flight, accomplish the repair/
modification in accordance with Part II of the Accomplishment 
Instructions of the service bulletin. Repeat the inspections 
required by paragraph (a) of this AD thereafter at intervals not to 
exceed 18 months.
    (c) 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), 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 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Atlanta ACO.

    (d) 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 May 5, 1997.
S.R. Miller,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-12252 Filed 5-8-97; 8:45 am]
BILLING CODE 4910-13-U