[Federal Register Volume 63, Number 176 (Friday, September 11, 1998)]
[Proposed Rules]
[Pages 48655-48658]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-24406]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-NM-315-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 all Lockheed Model L-1011-
385 series airplanes, that currently requires a one-time inspection to 
detect cracking of the bulkhead at fuselage station (FS) 1363 at butt 
line 42.5, and repair or additional inspections, if necessary. This 
action would add repetitive inspections to detect cracking of the 
bulkhead web and bulkhead cap (frame cap) at FS 1363, and repair, if 
necessary. This proposal is prompted by reports that additional, more 
extensive, fatigue cracking was found in the bulkhead web and cap. The 
actions specified by the proposed AD are intended to detect and correct 
cracking of the bulkhead web and cap, which could result in reduced 
structural integrity of the fuselage.

DATES: Comments must be received by October 26, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-114, 
Attention: Rules Docket No. 97-NM-315-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 Aeronautical Systems Support Company (LASSC), 
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, One Crown Center, 1895 Phoenix Boulevard, suite 
450, Atlanta, Georgia.

FOR FURTHER INFORMATION CONTACT: Thomas Peters, Aerospace Engineer, 
Systems and Flight Test Branch, ACE-116A, 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

[[Page 48656]]

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 97-NM-315-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. 97-NM-315-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    On June 9, 1995, the FAA issued AD 95-12-24, amendment 39-9277 (60 
FR 31624, June 16, 1995), applicable to all Lockheed Model L-1011-385 
series airplanes, to require a one-time visual inspection to detect 
cracking of the bulkhead at fuselage station (FS) 1363 in the area of 
the stiffeners at left and right butt line 42.5, and repair or 
additional inspections, if necessary. That action was prompted by 
reports indicating that fatigue cracking was found in the rear bulkhead 
at FS 1363. The requirements of that AD are intended to detect and 
correct fatigue cracking of the pressure bulkhead, which could result 
in reduced structural integrity of the fuselage.

Actions Since Issuance of Previous Rule

    Since the issuance of that AD, additional, more extensive, cracking 
has been found in the bulkhead web and cap in the area of FS 1363. Such 
cracking in the web has been attributed to high tension and shear 
stresses in the web and high tension loads in discontinuous stiffeners. 
Cracks initiated independently and concurrently at various locations in 
the web and cap. Cracks in the bulkhead cap initiated secondary fatigue 
cracks in the adjacent bulkhead web. Growth of such cracks could result 
in damage to the structure and consequent reduced structural integrity 
of the fuselage.
    Further, in the preamble to AD 95-12-24, the FAA indicated that the 
actions required by that AD were considered ``interim action'' and that 
further rulemaking action was being considered. The FAA now has 
determined that further rulemaking action is indeed necessary, and this 
proposed AD follows from that determination.

Explanation of Relevant Service Information

    The FAA has reviewed and approved Lockheed L-1011 Service Bulletin 
093-53-268, Revision 1, dated July 2, 1996. That service bulletin 
describes procedures for repetitive visual and eddy current surface 
scan inspections to detect cracking of the bulkhead web at FS 1363, and 
repair, if necessary. The procedures include inspections for cracking 
of webs, web stiffeners, and fastener holes. Procedures for repair 
include installing web doublers and a splice. That service bulletin 
also specifies that repair of cracking may be deferred if the cracking 
meets certain conditions.
    The service bulletin also describes an optional modification that 
involves removing fasteners; performing an eddy current bolt hole 
inspection; repair, if necessary; cold working of the fastener holes; 
and installation of new fasteners. The service bulletin specifies that 
this modification, if accomplished, would introduce a new threshold of 
18,000 flight cycles for the repetitive inspections of the bulkhead 
web.
    The FAA also has reviewed and approved Lockheed L-1011 Service 
Bulletin 093-53-272, dated November 12, 1996. That service bulletin 
describes procedures for repetitive visual, eddy current surface scan, 
eddy current bolt hole, and X-ray inspections to detect cracking of the 
bulkhead cap at FS 1363; and repair, if necessary. That service 
bulletin also describes an optional modification, which involves 
replacing the bulkhead cap, and cold working fastener holes. The 
service bulletin specifies that this modification, if accomplished, 
would introduce a new threshold of 18,000 flight cycles for the 
repetitive inspections of the bulkhead cap.

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 95-12-24 to continue to require a one-
time visual inspection to detect cracking of the bulkhead at FS 1363 at 
butt line 42.5, and repair or additional inspections, if necessary. The 
proposed AD also would add repetitive visual and eddy current surface 
scan inspections to detect cracking of the bulkhead web at FS 1363; 
repetitive visual, eddy current bolt hole, eddy current surface scan, 
and X-ray inspections to detect cracking of the bulkhead cap at FS 
1363; and repair, if necessary. The inspections would be required to be 
accomplished in accordance with the service bulletins described 
previously. This proposed AD also provides for modification of the 
bulkhead web or bulkhead cap, which, if accomplished, introduces a new 
threshold of 18,000 flight cycles for the repetitive inspections of the 
modified area.
    This proposed AD specifies that flight with a crack in the bulkhead 
web is allowed, provided that (1) the crack does not extend beyond a 
certain area, (2) the crack does not exceed a certain maximum length, 
(3) the horizontal stiffeners above and below the web crack have no 
detectable cracks, and (4) inspections of the bulkhead are repeated on 
a more frequent basis until repair is accomplished.

Other Relevant Rulemaking

    The FAA has previously issued AD 95-20-04 R1, amendment 39-9454 (60 
FR 63414, December 12, 1995), applicable to all Lockheed Model L-1011-
385-1 series airplanes. That AD requires implementation of a 
Supplemental Inspection Document program of structural inspections to 
detect fatigue cracking; and repair, if necessary. Because inspections 
specified by this proposed AD may overlap with certain inspections 
presently mandated by AD 95-20-04 R1, the FAA is considering further 
rulemaking action that would remove those inspections from the 
requirements of AD 95-20-04 R1.

Cost Impact

    There are approximately 236 airplanes of the affected design in the 
worldwide fleet. The FAA estimates that 118 airplanes of U.S. registry 
would be affected by this proposed AD.
    The inspection that is currently required by AD 95-12-24 takes 
approximately 16 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 inspection on U.S. operators is 
estimated to be $113,280, or $960 per airplane.
    The new inspections of the bulkhead web that are proposed in this 
AD action would take approximately 16 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 inspections of the bulkhead web 
proposed by this AD on U.S. operators is estimated to be $113,280, or 
$960 per airplane, per inspection cycle.
    The new inspections of the bulkhead cap that are proposed in this 
AD action would take approximately 40 work hours per airplane to 
accomplish, at an

[[Page 48657]]

average labor rate of $60 per work hour. Based on these figures, the 
cost impact of the inspections of the bulkhead cap proposed by this AD 
on U.S. operators is estimated to be $283,200, or $2,400 per airplane, 
per inspection cycle.
    Should an operator be required to accomplish the repair of cracking 
in the bulkhead web, it would take between 8 to 32 work hours per 
airplane (8 work hours for each cracked area) to accomplish the repair, 
at an average labor rate of $60 per work hour. Based on these figures, 
the cost impact of any necessary repair of the bulkhead web is 
estimated to be between $480 to $1,920 per airplane.
    Should an operator be required to accomplish the repair of cracking 
in the bulkhead cap, it would take approximately 200 work hours per 
airplane to accomplish the repair, at an average labor rate of $60 per 
work hour. Based on these figures, the cost impact of any necessary 
repair of the bulkhead cap is estimated to be $12,000 per airplane.
    The cost impact figures discussed above are 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.
    Should an operator elect to accomplish the optional modification of 
the bulkhead web that would be provided by this AD action, it would 
take approximately 48 work hours to accomplish, at an average labor 
rate of $60 per work hour. Based on these figures, the cost impact of 
the optional modification of the bulkhead web would be $2,880 per 
airplane.
    Should an operator elect to accomplish the optional modification of 
the bulkhead cap that would be provided by this AD action, it would 
take approximately 200 work hours to accomplish, at an average labor 
rate of $60 per work hour. Based on these figures, the cost impact of 
the optional modification of the bulkhead cap would be $12,000 per 
airplane.

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 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 39-9277 (60 FR 
31624, June 16, 1995), and by adding a new airworthiness directive 
(AD), to read as follows:

Lockheed: Docket 97-NM-315-AD. Supersedes AD 95-12-24, amendment 39-
9277.

    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 request approval for an 
alternative method of compliance in accordance with paragraph (i) 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 cracking of the bulkhead web and cap, 
which could result in reduced structural integrity of the fuselage, 
accomplish the following:

Restatement of the Requirements of AD 95-12-24, Amendment 39-9277

    (a) Prior to the accumulation of 18,000 total landings, or 
within 30 days after July 3, 1995 (the effective date of AD 95-12-
24, amendment 39-9277), whichever occurs later, perform a visual 
inspection to detect cracking of the bulkhead at fuselage station 
(FS) 1363 in the area of the stiffeners at left and right butt line 
(BL) 42.5; in accordance with the procedures specified in paragraphs 
2.A. and 2.B. of Part I of the Accomplishment Instructions of 
Lockheed L-1011 Service Bulletin 093-53-268, dated April 15, 1993; 
or in accordance with the procedures specified in paragraphs 2.A. 
and 2.B. of Part II of the Accomplishment Instructions of Lockheed 
L-1011 Service Bulletin 093-53-268, Revision 1, dated July 2, 1996.

    Note 2: This AD does not require that the eddy current 
inspection referenced in paragraph 2.B. of Part I of the 
Accomplishment Instructions of Lockheed L-1011 Service Bulletin 093-
53-268, dated April 15, 1993; and referenced in paragraph 2.B. of 
Part II of the Accomplishment Instructions of Lockheed L-1011 
Service Bulletin 093-53-268, Revision 1, dated July 2, 1996; be 
accomplished as a requirement of paragraph (a) of this AD.

    (b) Except as provided by paragraph (d) of this AD, if any 
cracking of the bulkhead is detected below waterline (WL) 117 during 
any inspection performed in accordance with paragraph (a) of this 
AD: Prior to further flight, perform the inspections required by 
paragraphs (b)(1), (b)(2), and (b)(3) of this AD, in accordance with 
Lockheed Document LCC-7622-373, dated May 9, 1995. Prior to further 
flight, repair any cracking of the bulkhead cap found during these 
inspections, in accordance with Lockheed Document LCC-7622-374, 
dated May 9, 1995.
    (1) Perform a bolt hole eddy current inspection to detect 
cracking of the eight fastener holes at the intersection of the 
vertical stiffener at BL 42.5 and the bulkhead cap vertical flange; 
and
    (2) Perform a bolt hole eddy current inspection to detect 
cracking at eight fastener locations in the bulkhead cap lower 
flange that connect the lower fuselage skin panel to the frame at 
the BL 42.5 vertical stiffener; and
    (3) Perform a visual inspection to detect stress corrosion 
cracking of the accessible portions of the fillet radius of the 
bulkhead cap.
    (c) Except as provided by paragraph (d) of this AD, if any 
cracking of the bulkhead is detected at or above WL 117 during any 
inspection performed in accordance with paragraph (a) of this AD: 
Prior to further flight, repair the bulkhead cracking in accordance 
with the procedures specified in Part II of the Accomplishment 
Instructions of Lockheed L-1011 Service Bulletin 093-53-268, dated 
April 15, 1993; or in accordance with the procedures specified in 
Part III of the Accomplishment Instructions of Lockheed L-1011 
Service Bulletin 093-53-268, Revision 1, dated July 2, 1996.
    (d) Continued flight with cracking of the bulkhead is permitted, 
provided that the

[[Page 48658]]

conditions specified in paragraph 1.C. of the Planning Information 
of Lockheed L-1011 Service Bulletin 093-53-268, dated April 15, 
1993; or Revision 1, dated July 2, 1996; are met. For flight with 
cracking, both the visual and eddy current inspections specified in 
paragraphs 2.B. and 2.C. of Part I of the Accomplishment 
Instructions of Lockheed L-1011 Service Bulletin 093-53-268, dated 
April 15, 1993; or specified in paragraphs 2.B. and 2.C. of Part II 
of the Accomplishment Instructions of Lockheed L-1011 Service 
Bulletin 093-53-268, Revision 1, dated July 2, 1996; must be 
accomplished prior to returning the aircraft to service. These 
visual and eddy current inspections must be repeated within 900 
landings. Prior to the accumulation of 1,800 total landings, these 
inspections must be terminated by the installation of the repair 
specified in Part II of the Accomplishment Instructions of Lockheed 
L-1011 Service Bulletin 093-53-268, dated April 15, 1993; or by 
installation of the repair specified in Part III of the 
Accomplishment Instructions of Lockheed L-1011 Service Bulletin 093-
53-268, Revision 1, dated July 2, 1996.

New Requirements of This of AD

    (e) Prior to the accumulation of 18,000 total landings, or 
within 6 months after the effective date of the AD, whichever occurs 
later, perform a visual and eddy current surface scan inspection for 
cracking of the bulkhead web at FS 1363, in accordance with Lockheed 
L-1011 Service Bulletin 093-53-268, Revision 1, dated July 2, 1996.
    (1) If no cracking of the bulkhead web is detected, except as 
provided by paragraph (f) of this AD, repeat the visual and eddy 
current surface scan inspections thereafter at intervals not to 
exceed 2,000 landings.
    (2) If cracking of the bulkhead web is detected, and that 
cracking is within the limits specified in Part I of the 
Accomplishment Instructions of the service bulletin: Accomplish the 
requirements of either paragraph (e)(2)(i) or (e)(2)(ii) of this AD, 
in accordance with the service bulletin. Except as provided by 
paragraph (f) of this AD, repeat the inspections thereafter at 
intervals not to exceed 2,000 landings after repair of the cracking.
    (i) Prior to further flight, repair the cracking. Or
    (ii) Repeat the inspections specified in Part I of the 
Accomplishment Instructions of the service bulletin at intervals not 
to exceed 900 landings, and repair the cracking within 1,800 
landings after the cracking was detected.
    (3) If cracking of the bulkhead web is detected, and that 
cracking is outside the limits specified in Part I of the 
Accomplishment Instructions of the service bulletin: Prior to 
further flight, repair in accordance with Part III of the 
Accomplishment Instructions of the service bulletin. Except as 
provided by paragraph (f) of this AD, repeat the inspections 
thereafter at intervals not to exceed 2,000 landings.
    (f) For airplanes on which modification of the bulkhead web is 
accomplished in accordance with Part IV of the Accomplishment 
Instructions of Lockheed L-1011 Service Bulletin 093-53-268, 
Revision 1, dated July 2, 1996: Repeat the inspections specified in 
paragraph (e) of this AD within 18,000 landings after accomplishment 
of the modification, in accordance with the service bulletin.
    (g) Prior to the accumulation of 18,000 total landings, or 
within 6 months after the effective date of this AD, whichever 
occurs later, perform visual, bolt hole eddy current, eddy current 
surface scan, and X-ray inspections for cracking of the bulkhead cap 
at FS 1363, in accordance with Lockheed L-1011 Service Bulletin 093-
53-272, dated November 12, 1996.
    (1) If no cracking of the bulkhead cap is detected, except as 
provided by paragraph (h) of this AD, repeat the inspections 
thereafter at intervals not to exceed 2,000 landings, in accordance 
with the service bulletin.
    (2) If any cracking of the bulkhead cap is detected, accomplish 
the requirements of either paragraph (g)(2)(i) or (g)(2)(ii) of this 
AD, in accordance with the service bulletin.
    (i) Prior to further flight, repair in accordance with Part I of 
the Accomplishment Instructions of the service bulletin. Thereafter, 
repeat the inspections at intervals not to exceed 2,000 landings. Or
    (ii) Prior to further flight, replace the bulkhead cap, in 
accordance with Part II of the Accomplishment Instructions of the 
service bulletin. Following such replacement, repeat the inspection 
within 18,000 landings, in accordance with the service bulletin.
    (h) For airplanes on which replacement of the bulkhead cap is 
accomplished in accordance with Part II of the Accomplishment 
Instructions of Lockheed L-1011 Service Bulletin 093-53-272, dated 
November 12, 1996: Repeat the inspections specified in paragraph (g) 
of this AD within 18,000 landings after accomplishment of the 
replacement, in accordance with the service bulletin.
    (i) 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 Aircraft Certification 
Office (ACO), FAA, Small Airplane Directorate. 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 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Atlanta ACO.

    (j) 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 4, 1998.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 98-24406 Filed 9-10-98; 8:45 am]
BILLING CODE 4910-13-P