[Federal Register Volume 60, Number 248 (Wednesday, December 27, 1995)]
[Rules and Regulations]
[Pages 66870-66872]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-31297]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 95-NM-246-AD; Amendment 39-9469; AD 95-26-11]
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-1011-385 series airplanes,
that currently requires visual inspections to detect cracking of the
fittings that attach the aft pressure bulkhead to the fuselage
stringers. That AD also currently requires replacement of cracked
fittings, and repair of adjacent structure if found to be cracked. This
amendment requires new repetitive inspections to detect cracking of the
fittings and of the splice tab of the aft pressure bulkhead, and
corrective actions, if necessary. This amendment is prompted by the
results of the visual inspections performed in accordance with the
existing AD, which indicate that the visual inspection is inadequate to
detect fatigue cracking. The actions specified in this AD are intended
to prevent fatigue cracking of the aft pressure bulkhead, which could
lead to failure of the end fittings and splice tabs, and subsequent
rapid decompression of the airplane during flight.
DATES: Effective January 11, 1996.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of January 11, 1996.
Comments for inclusion in the Rules Docket must be received on or
before February 26, 1996.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Transport Airplane Directorate, ANM-103,
Attention: Rules Docket No. 95-NM-246-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,
Atlanta Aircraft Certification Office, Small Airplane Directorate,
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 Peters, Aerospace Engineer,
Systems and Flight Test Branch, ACE-116A, FAA, Atlanta Aircraft
Certification Office, Small Airplane Directorate, Campus Building, 1701
Columbia Avenue, Suite 2-160, College Park, Georgia; telephone (404)
305-7367; fax (404) 305-7348.
SUPPLEMENTARY INFORMATION: On September 6, 1995, the FAA issued AD 95-
18-52, amendment 39-9366 (60 FR 47465, September 13, 1995), which is
applicable to all Lockheed Model L-1011-385 series airplanes. That AD
requires repetitive detailed visual inspections to detect cracking of
the fittings that attach the aft pressure bulkhead to the fuselage
stringers at stringers 1 through 10 and at stringers 64 through 56, and
various follow-on actions. That action was prompted by reports of
cracks found in these fittings. The actions required by that AD are
intended to prevent fatigue cracking that can lead to failure of the
fittings that attach the aft pressure bulkhead to the fuselage
stringer, and subsequent rapid decompression of the airplane during
flight.
The FAA has reviewed the findings from the visual inspections
performed in accordance with AD 95-18-52, and from eddy current
inspections performed voluntarily by an operator. The eddy current
inspections revealed findings of cracks in the end fittings; these same
fittings had been inspected previously using the visual inspection
technique required by the existing AD and this cracking was identified.
In light of these findings, the FAA has determined that the currently
required visual inspections are inadequate to detect all fatigue
cracking. Such fatigue cracking, if not detected and corrected in a
timely manner, could lead to failure of the fittings and splice tabs of
the aft pressure bulkhead, and subsequently
[[Page 66871]]
could result in rapid decompression of the airplane during flight.
The FAA has reviewed and approved Lockheed L-1011 Service Bulletin
093-53-105, Revision 1, dated November 17, 1995, which describes
procedures for:
1. Repetitive eddy current surface scan (ECSS) inspections to
detect cracking of the end fittings that attach the aft pressure
bulkhead to the fuselage stringers at stringers 1 through 14 (right
side) and at stringers 52 through 64 (left side);
2. Repetitive ECSS inspections to detect cracking of the lower (or
inner) surface of the upper bonded splice tab of the bulkhead assembly
at stringers 1 through 14 and at stringers 52 through 64.
3. If any end fitting is found cracked, replacement of a fitting
with a new fitting without pilot holes, rework of the fitting, and
various follow-on actions (i.e., bolt hole eddy current, ECSS, and
borescope inspections; and repair) of the inner and outer tee caps; and
4. A bolt hole eddy current inspection to detect cracking of the
forward flange of the inner tee cap, if any fastener is found cracked;
and repair, if necessary.
Accomplishment of the ECSS inspections described in this service
bulletin would eliminate the need for the repetitive visual
inspections.
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 95-18-52 to continue to require repetitive detailed
visual inspections to detect cracking of the fittings that attach the
aft pressure bulkhead to the fuselage stringers at stringers 1 through
10 (right side) and at stringers 56 through 64 (left side). This AD
adds a requirement to conduct repetitive ECSS inspections to detect
cracking of the end fittings and of the splice tab at stringers 1
through 14 (right side) and at stringers 52 through 64 (left side) of
the aft pressure bulkhead, and corrective actions, if necessary.
Once the ECSS inspections are initiated, the repetitive visual
inspection requirements of this AD are terminated.
The previous requirement of AD 95-18-52 to submit a report of
inspection findings to the FAA has been deleted from this AD.
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 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-246-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 USC 106(g), 40101, 40113, 44701.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by removing amendment 39-9366 (60 FR
47465, September 13, 1995), and by adding a new airworthiness directive
(AD), amendment 39-9469, to read as follows:
95-26-11 Lockheed: Amendment 39-9469. Docket 95-NM-246-AD.
Supersedes AD 95-18-52, Amendment 39-9366.
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 (h) 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 cracking of the aft pressure bulkhead, which
could lead to failure of the end fittings and splice tab, and
[[Page 66872]]
subsequent rapid decompression of the airplane during flight,
accomplish the following:
Restatement of Actions Required by AD 95-18-52, Amendment 39-9366
Perform a detailed visual inspection to detect cracking of the
fittings that attach the aft pressure bulkhead to the fuselage
stringers (hereinafter referred to as ``fittings'') at stringers 1
through 10 (right side) and at stringers 56 through 64 (left side),
at the later of the times specified in either paragraph (a)(1) or
(a)(2) of this AD.
(1) Prior to the accumulation of 20,000 total flight cycles; or
(2) Within the next 25 flight cycles or 10 days after September
28, 1995 (the effective date of AD 95-18-52, amendment 39-9366),
whichever occurs earlier.
(b) If any cracking is detected in the fitting at either
stringer 10 or stringer 56 during the inspection required by
paragraph (a) of this AD, prior to further flight, perform a
detailed visual inspection to detect cracking of the next adjacent
fitting (i.e., at stringer 11 or 55). If cracking is detected in
that fitting, prior to further flight, perform a detailed visual
inspection to detect cracking of the next adjacent fitting (i.e., at
stringer 12 or 54). If cracking is detected in that fitting, prior
to further flight, continue to perform detailed visual inspections
to detect cracking of the next adjacent fitting(s) until such a
fitting is found to be free of cracks.
(c) If any cracked fitting is detected during the inspections
required by either paragraph (a) or (b) of this AD, prior to further
flight, accomplish the requirements of paragraphs (c)(1) and (c)(2)
of this AD.
(1) Replace the cracked fitting with a new fitting, or with a
serviceable fitting on which a detailed visual inspection has been
performed previously to detect cracking and that has been found to
be free of cracks; and
(2) Perform a detailed visual inspection to detect cracking in
the radius at the lower end of the vertical leg of the bulkhead T-
shaped frame between the stringer locations on either side of the
stringer having the cracked fitting. If any cracked T-shaped frame
is detected, prior to further flight, repair in accordance with a
method approved by the Manager, Atlanta Aircraft Certification
Office (ACO), FAA, Small Airplane Directorate.
(d) Repeat the inspections and other necessary actions required
by paragraphs (a), (b), and (c) of this AD at intervals not to
exceed 1,800 flight cycles or 3,000 flight hours, whichever occurs
earlier, until paragraph (e) of this AD is accomplished.
New Actions Required by This Amendment
(e) Except as provided by paragraph (f) of this AD, prior to the
accumulation of 20,000 flight cycles, or within 30 days after the
effective date of this AD, whichever occurs later, accomplish the
requirements of both paragraphs (e)(1) and (e)(2) of this AD, in
accordance with Lockheed L-1011 Service Bulletin 093-53-105,
Revision 1, dated November 17, 1995. Repeat the ECSS inspections
thereafter at intervals not to exceed 2,500 flight cycles.
Accomplishment of the eddy current surface scan (ECSS) inspection
constitutes terminating action for the repetitive inspection
requirements of paragraph (d) of this AD.
(1) Perform an ECSS inspection to detect cracking of the
fittings at stringers 1 through 14 (right side) and at stringers 52
through 64 (left side), in accordance with the service bulletin.
Except as provided by paragraph (g) of this AD, if any cracking is
detected, prior to further flight, replace the fitting with a new
fitting without pilot holes, rework the fitting, and perform various
follow-on actions (i.e., bolt hole eddy current, ECSS, and borescope
inspections; and repair) of the inner and outer tee caps, in
accordance with the service bulletin. And
(2) Perform an ECSS inspection to detect cracking of the lower
(or inner) surface of the upper bonded splice tab of the bulkhead
assembly at stringers 1 through 14 (right side) and at stringers 52
through 64 (left side), in accordance with the service bulletin.
(i) Except as provided by paragraph (g) of this AD, if any
cracking is detected at the upper bonded splice tab, repair in
accordance with a method approved by the Manager, Atlanta ACO, FAA,
Small Airplane Directorate.
(ii) Except as provided by paragraph (g) of this AD, if any
cracking is detected at a fastener, prior to further flight, perform
a bolt hole eddy current (BHEC) inspection to detect cracking of the
forward flange of the inner tee cap, in accordance with the service
bulletin. If any cracking is detected, prior to further flight,
repair in accordance with the service bulletin.
(f) Accomplishment of the initial ECSS inspections required by
paragraph (e) of this AD may be deferred to a date within 120 days
after the effective date of this AD provided that, in the interim, a
visual inspection as specified in paragraph (a) of this AD is
accomplished within 30 days after the effective date of this AD and
repeated thereafter at intervals not to exceed 50 flight cycles.
Once the ECSS inspections begin, the visual inspections may be
terminated.
(g) If two or more adjacent fittings on both sides of the
cracked fittings or bonded splice tabs/fasteners are determined to
be free of cracks by the ECSS inspection required by paragraph
(e)(1) and (e)(2) of this AD, repeat the ECSS inspection of the
adjacent fittings thereafter at intervals not to exceed 600 flight
cycles until the cracked fittings or splice tabs/fasteners are
replaced or repaired. Within 2,500 total flight cycles after finding
the crack, replace or repair the cracked fitting and/or splice tab/
fasteners in accordance with Lockheed L-1011 Service Bulletin 093-
53-105, Revision 1, dated November 17, 1995.
(h) 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.
(i) 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.
(j) The actions shall be done in accordance with Lockheed L-1011
Service Bulletin 093-53-105, Revision 1, dated November 17, 1995.
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, Atlanta Aircraft Certification
Office, Small Airplane Directorate, 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.
(k) This amendment becomes effective on January 11, 1996.
Issued in Renton, Washington, on December 18, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 95-31297 Filed 12-26-95; 8:45 am]
BILLING CODE 4910-13-U
