[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
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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
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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]
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