[Federal Register Volume 60, Number 154 (Thursday, August 10, 1995)]
[Rules and Regulations]
[Pages 40753-40754]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-19119]



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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 95-NM-132-AD; Amendment 39-9332; AD 95-17-03]


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment supersedes an existing airworthiness directive 
(AD), applicable to all Lockheed Model L-1011 series airplanes, that 
currently requires a visual inspection to detect cracks of the forward 
or aft side of the aft pressure bulkhead, and repair, if necessary. 
This amendment requires various inspections to detect cracks or other 
discrepancies of the aft pressure bulkhead, and repair, if necessary. 
This amendment is prompted by a recent report of in-flight loss of 
cabin pressure on a Model L-1011-385 series airplane due to a rupture 
of the aft pressure bulkhead as a result of fatigue-related cracking. 
The actions specified in this AD are intended to prevent such fatigue 
cracking, which could result in rupture of the aft pressure bulkhead 
and subsequent depressurization of the cabin.

DATES: Effective August 25, 1995.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of August 25, 1995.
    Comments for inclusion in the Rules Docket must be received on or 
before October 25, 1995.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 95-NM-132-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056.
    The service information referenced in this AD may be obtained from 
Lockheed Aeronautical Systems Support Company, 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; or at the Office of the Federal Register, 800 North Capitol 
Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Thomas B. Peters, Aerospace Engineer, 
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: On January 16, 1990, the FAA issued AD 90-
03-11, amendment 39-6492 (55 FR 2639, January 26, 1990), applicable to 
all Lockheed Model L-1011 series airplanes, to require a one-time 
visual inspection to detect cracks of the forward or aft side of the 
aft pressure bulkhead, and repair, if necessary. That action was 
prompted by a report of loss of cabin pressure in the aft pressure 
bulkhead, which resulted in a rupture of a single gore panel. The 
actions required by that AD are intended to prevent structural failure 
of the aft pressure bulkhead.
    Since the issuance of that AD, the FAA has received a report of 
loss of cabin pressure on a Model L-1011-385 series airplane, which 
occurred while the airplane was cruising at 31,000 feet. Investigation 
revealed a 4-inch long crack that was oriented in a circumferential 
direction in the gore panel of the aft pressure bulkhead located at the 
inner edge of the 6-inch doubler. The crack ruptured rapidly until it 
was stopped by the anti-tear strap. The cause of the cracking has been 
attributed to fatigue. The airplane had accumulated 35,810 total flight 
hours and 19,688 total flight cycles. Fatigue-related cracking in the 
aft pressure bulkhead, if not detected and corrected in a timely 
manner, could result in rupture of the aft pressure bulkhead and 
subsequent depressurization of the cabin.
    This recent incident is similar to the incident that occurred in 
1989, which prompted the issuance of AD 90-30-11 to require a one-time 
visual inspection to detect cracks of the aft pressure bulkhead. The 
FAA finds that repetitive non-destructive inspections of the affected 
airplanes are necessary in order to ensure that the unsafe condition 
presented by fatigue cracking is corrected, and to provide an 
acceptable level of safety.
    The FAA has reviewed and approved Lockheed L-1011 Service Bulletin 
093-53-258, dated February 20, 1990, which describes procedures for:
    1. Performing a visual inspection to detect cracks or other 
discrepancies (including oil can buckles) of the upper gore panels from 
either the forward side or the aft side of the aft pressure bulkhead;
    2. Performing an eddy current inspection to detect cracks of the 
aft left-hand side and the forward right-hand side of the aft pressure 
bulkhead; and
    3. Repair of gore panels, if any crack or discrepancy is detected.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other airplanes of this same type design, this AD 
supersedes AD 90-03-11 to require repetitive inspections to detect 
cracks or other discrepancies (including oil can buckles) of the upper 
gore panels from either the forward side or the aft side of the aft 
pressure bulkhead, and various follow-on inspections. This AD also 
requires an eddy current inspection to detect cracks of the aft left-
hand side and the forward right-hand side of the aft pressure bulkhead. 
The actions would be required to be accomplished in accordance with the 
service bulletin described previously. If any crack or discrepancy is 
detected, a repair would be required to be accomplished in accordance 
with a method approved by the FAA.
    Since a situation exists that requires the immediate adoption of 
this regulation, it is found that notice and opportunity for prior 
public comment hereon are impracticable, and that good cause exists for 
making this amendment effective in less than 30 days.

Comments Invited

    Although this action is in the form of a final rule that involves 
requirements affecting flight safety and, thus, was not preceded by 
notice and an opportunity for public comment, comments are invited on 
this rule. Interested persons are invited to comment on this 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 under the caption ADDRESSES. All 
communications received on or before the closing date for comments will 
be 

[[Page 40754]]
considered, and this rule may be amended in light of the comments 
received. Factual information that supports the commenter's ideas and 
suggestions is extremely helpful in evaluating the effectiveness of the 
AD action and determining whether additional rulemaking action would be 
needed.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the 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 that 
summarizes each FAA-public contact concerned with the substance of this 
AD will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this rule must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 95-NM-132-AD.'' The postcard will be date stamped and 
returned to the commenter.
    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.
    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft, and that it is not a ``significant regulatory 
action'' under Executive Order 12866. It has been determined further 
that this action involves an emergency regulation under DOT Regulatory 
Policies and Procedures (44 FR 11034, February 26, 1979). If it is 
determined that this emergency regulation otherwise would be 
significant under DOT Regulatory Policies and Procedures, a final 
regulatory evaluation will be prepared and placed in the Rules Docket. 
A copy of it, if filed, 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 U.S.C. 106(g), 40101, 40113, 44701.
Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing amendment 39-6492 (55 FR 
2639, January 26, 1990), and by adding a new airworthiness directive 
(AD), amendment 39-9332, to read as follows:

95-17-03  Lockheed Aeronautical System Company: Amendment 39-9332. 
Docket 95-NM-132-AD. Supersedes AD 90-03-11, Amendment 39-6492.

    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 use the authority 
provided in paragraph (c) 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 fatigue-related cracking in the aft pressure 
bulkhead, which could result in rupture of the aft pressure bulkhead 
and subsequent depressurization of the cabin, accomplish the 
following:
    (a) Prior to the accumulation of 12,000 total landings, or 
within 30 days after the effective date of this AD, whichever occurs 
later; unless previously accomplished within the last 2,500 flight 
cycles; accomplish either paragraph (a)(1) or (a)(2) of this AD in 
accordance with Lockheed L-1011 Service Bulletin 093-53-258, dated 
February 20, 1990.
    (1) Perform a visual inspection to detect cracks or other 
discrepancies (including oil can buckles) of the upper gore panels 
from either the forward side or the aft side of the aft pressure 
bulkhead, in accordance with paragraph 2.B. of the Accomplishment 
Instructions of the service bulletin. Within 90 days after 
accomplishing that visual inspection, perform an eddy current 
inspection to detect cracks of the aft left-hand side and the 
forward right-hand side of the aft pressure bulkhead, in accordance 
with paragraph 2.C. of the Accomplishment Instructions of the 
service bulletin. Repeat the eddy current inspection thereafter at 
intervals not to exceed 2,500 flight cycles; or
    (2) Perform an eddy current inspection to detect cracks of the 
aft left-hand side and the forward right-hand side of the aft 
pressure bulkhead, in accordance with the service bulletin. Repeat 
the eddy current inspection thereafter at intervals not to exceed 
2,500 flight cycles.
    (b) If any crack or discrepancy is detected during any 
inspection required by this AD, prior to further flight, repair in 
accordance with Figure 4 of Lockheed L-1011 Service Bulletin 093-53-
258, dated February 20, 1990; or in accordance with a method 
approved by the Manager, Atlanta Aircraft Certification Office 
(ACO), FAA, Small Airplane Directorate.
    (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 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.

    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.
    (e) The inspections shall be done in accordance with Lockheed L-
1011 Service Bulletin 093-53-258, dated February 20, 1990. 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 30080. Copies may be inspected 
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 30337-2748; or 
at the Office of the Federal Register, 800 North Capitol Street, 
NW., suite 700, Washington, DC.
    (f) This amendment becomes effective on August 25, 1995.

    Issued in Renton, Washington, on July 28, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 95-19119 Filed 8-9-95; 8:45 am]
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