AD Amdt-39-9469

[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 [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[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