[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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