[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
