[Federal Register Volume 64, Number 193 (Wednesday, October 6, 1999)]
[Proposed Rules]
[Pages 54230-54232]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-25934]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 99-NM-233-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 supersedure of an existing 
airworthiness directive (AD), applicable to certain Lockheed Model L-
1011-385 series airplanes, that currently requires repetitive 
inspections to detect cracking of the canted pressure bulkhead at 
fuselage station (FS) 1212, and repetitive inspections to detect 
cracking of the web at the fastener rows of the vertical stiffener-to-
web; and repair or replacement of the web with a new web, if necessary. 
This action would require that the initial inspections be accomplished 
at a reduced threshold. This proposal is prompted by a report of 
fatigue cracking of the canted pressure bulkhead at FS 1212. The 
actions specified by the proposed AD are intended to detect and correct 
fatigue cracking of the canted pressure bulkhead at FS 1212, which 
could result in blowout of a panel between adjacent stiffeners and 
consequent cabin depressurization.

DATES: Comments must be received by November 22, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 99-NM-233-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 Martin Aircraft & Logistics Center, 120 Orion 
Street, Greenville, South Carolina 29605. 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, Program Manager,

[[Page 54231]]

Program Management and Services Branch, ACE-118A, 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 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 99-NM-233-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. 99-NM-233-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On September 26, 1996, the FAA issued AD 96-20-10, amendment 39-
9776 (61 FR 53044, October 10, 1996), applicable to certain Lockheed 
Model L-1011-385 series airplanes, to require inspections to detect 
cracking of the canted pressure bulkhead at fuselage station (FS) 1212, 
and inspections to detect cracking of the web at the fastener rows of 
the vertical stiffener-to-web; and repair or replacement of the web 
with a new web, if necessary. That action was prompted by a report of 
fatigue cracking of the canted pressure bulkhead at FS 1212. The 
requirements of that AD are intended to detect and correct fatigue 
cracking of the canted pressure bulkhead at FS 1212, which could result 
in blowout of a panel between adjacent stiffeners and consequent cabin 
depressurization.

Actions Since Issuance of Previous Rule

    Since the issuance of that AD, the FAA has received an additional 
report of fatigue cracking in the subject area on one of these 
airplanes. The airplane on which the cracking occurred had accumulated 
fewer flight cycles at the time the cracking was detected than the 
number of flight cycles specified as the inspection threshold in AD 96-
20-10.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Lockheed L-1011 Service Bulletin 
093-53-277, Revision 1, dated November 19, 1998, which describes 
procedures for repetitive detailed visual inspections to detect 
cracking of the entire aft surface of the canted pressure bulkhead at 
FS 1212 between left buttock line (LBL) 103 and right buttock line 
(RBL) 103, and repetitive optical inspections (i.e., using a borescope 
or mirror) to detect cracking of the web at the fastener rows of the 
vertical stiffener-to-web; and repair or replacement of the web with a 
new web, if necessary. Accomplishment of the actions specified in the 
service bulletin is intended to adequately address the identified 
unsafe condition.

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 96-20-10 to continue to require 
repetitive inspections to detect cracking of the canted pressure 
bulkhead at FS 1212, and repetitive inspections to detect cracking of 
the web at the fastener rows of the vertical stiffener-to-web; and 
repair or replacement of the web with a new web, if necessary. The 
proposed AD would require that the initial inspections be accomplished 
at a reduced threshold. The actions would be required to be 
accomplished in accordance with the service bulletin described 
previously.

Explanation of Changes Made to Requirements of AD 96-20-10

    The FAA has restated the compliance time in terms of flight cycles, 
instead of landings. This is consistent with the compliance times 
stated in the service bulletin. In addition, the inspection identified 
in AD 96-20-10 as a ``close visual inspection'' is identified in this 
proposed AD as a ``detailed visual inspection.'' Furthermore, the FAA 
has added a note to the proposed AD to clarify the definition of a 
detailed visual inspection.

Cost Impact

    There are approximately 235 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 116 airplanes of U.S. registry 
would be affected by this proposed AD. The requirements of this 
proposed AD would not add any new additional economic burden on 
affected operators, other than the costs that are associated with 
beginning the inspections at an earlier time than would have been 
required by AD 96-20-10 (initial inspection is now required within 
18,000 flight cycles, rather than 20,000 flight cycles).
    The inspections that are currently required by AD 96-20-10, and 
retained in this proposed AD, take approximately 5 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 currently required 
actions on U.S. operators is estimated to be $34,800, or $300 per 
airplane, per inspection cycle.
    The cost impact figure discussed above is 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.

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

[[Page 54232]]

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 39-9776 (61 FR 
53044, October 10, 1996), and by adding a new airworthiness directive 
(AD), to read as follows:

Lockheed: Docket 99-NM-233-AD. Supersedes AD 96-20-10, Amendment 39-
9776.

    Applicability: Model L-1011-385 series airplanes; serial numbers 
1013 through 1250 inclusive; 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)(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 detect and correct fatigue cracking of the canted pressure 
bulkhead at fuselage station (FS) 1212, which could result in 
blowout of a panel between adjacent stiffeners and consequent cabin 
depressurization, accomplish the following:

Repetitive Inspections

    (a) Perform a detailed visual inspection to detect cracking of 
the entire aft surface of the canted pressure bulkhead at FS 1212 
between left buttock line (LBL) 103 and right buttock line (RBL) 
103; and perform an optical inspection using a borescope or other 
optical device to detect cracking of the web at the fastener rows of 
the vertical stiffener-to-web; in accordance with Lockheed L-1011 
Service Bulletin 093-53-277, dated July 2, 1996, or Revision 1, 
dated November 19, 1998; at the earlier of the times specified in 
paragraphs (a)(1) and (a)(2) of this AD. Thereafter, repeat these 
inspections at intervals not to exceed 1,000 flight cycles.
    (1) Prior to the accumulation of 20,000 total flight cycles, or 
within 60 days after October 25, 1996 (the effective date of AD 96-
20-10), whichever occurs later; or
    (2) Prior to the accumulation of 18,000 total flight cycles, or 
within 60 days after the effective date of this AD, whichever occurs 
later.

    Note 2: For the purposes of this AD, a detailed visual 
inspection is defined as: ``An intensive visual examination of a 
specific structural area, system, installation, or assembly to 
detect damage, failure, or irregularity. Available lighting is 
normally supplemented with a direct source of good lighting at 
intensity deemed appropriate by the inspector. Inspection aids such 
as mirror, magnifying lenses, etc., may be used. Surface cleaning 
and elaborate access procedures may be required.''

Repair

    (b) If any cracking is found during any inspection required by 
paragraph (a) of this AD, prior to further flight, accomplish either 
paragraph (b)(1) or (b)(2) of this AD.
    (1) Accomplish either paragraph (b)(1)(i) or (b)(1)(ii) of this 
AD, as applicable.
    (i) If the cracking is found in an area that is specified in 
Lockheed Repair Drawing LCC-7622-385, repair in accordance with 
Lockheed L-1011 Service Bulletin 093-53-277, dated July 2, 1996, or 
Revision 1, dated November 19, 1998. Accomplishment of a repair 
constitutes terminating action for the repetitive inspections 
required by paragraph (a) of this AD at the repaired location only. 
Or
    (ii) If the cracking is found in an area that is not specified 
in Lockheed Repair Drawing LCC-7622-385, repair in accordance with a 
method approved by the Manager, Atlanta Aircraft Certification 
Office (ACO), FAA, Small Airplane Directorate.
    (2) Replace the entire web with a new web in accordance with 
Lockheed L-1011 Service Bulletin 093-53-277, dated July 2, 1996, or 
Revision 1, dated November 19, 1998. Such replacement constitutes 
terminating action for the repetitive inspections required by 
paragraph (a) of this AD.

Alternative Methods of Compliance

    (c)(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.
    (c)(2) Alternative methods of compliance, approved previously in 
accordance with AD 96-20-10, amendment 39-9776, are approved as 
alternative methods of compliance with paragraph (b) 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.

Special Flight Permits

    (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 September 29, 1999.
D.L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 99-25934 Filed 10-5-99; 8:45 am]
BILLING CODE 4910-13-U