[Federal Register Volume 77, Number 125 (Thursday, June 28, 2012)]
[Proposed Rules]
[Pages 38547-38552]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2012-15601]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2012-0645; Directorate Identifier 2011-NM-052-AD]
RIN 2120-AA64
Airworthiness Directives; The Boeing Company Airplanes
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: We propose to supersede an existing airworthiness directive
(AD) that applies to all The Boeing Company Model 737-100, -200, -200C,
-300, -400, and -500 series airplanes. The existing AD currently
requires repetitive inspections to detect cracking in the web of the
aft pressure bulkhead at body station 1016 at the aft fastener row
attachment to the ``Y'' chord, and corrective actions if necessary.
That AD was prompted by several reports of fatigue cracking at that
location, which could result in rapid decompression of the fuselage.
Since we issued that AD, we have received additional reports of cracks
found in the aft pressure bulkhead. This proposed AD would add various
inspections for discrepancies at the aft pressure bulkhead, and related
investigative and corrective actions if necessary. We are proposing
this AD to detect and correct such fatigue cracking, which could result
in rapid decompression of the fuselage.
DATES: We must receive comments on this proposed AD by August 13, 2012.
ADDRESSES: You may send comments, using the procedures found in 14 CFR
11.43 and 11.45, by any of the following methods:
Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
Fax: 202-493-2251.
Mail: U.S. Department of Transportation, Docket
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New
Jersey Avenue SE., Washington, DC 20590.
Hand Delivery: Deliver to Mail address above between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
For service information identified in this proposed AD, contact
Boeing Commercial Airplanes, Attention: Data & Services Management,
P.O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; telephone 206-
544-5000, extension 1; fax 206-766-5680; Internet https://www.myboeingfleet.com. You may review copies of the referenced service
information at the FAA, Transport Airplane Directorate, 1601 Lind
Avenue SW., Renton, Washington. For information on the availability of
this material at the FAA, call 425-227-1221.
Examining the AD Docket
You may examine the AD docket on the Internet at http://www.regulations.gov; or in person at the Docket Management Facility
between 9 a.m. and 5 p.m., Monday through Friday, except Federal
holidays. The AD docket contains this proposed AD, the regulatory
evaluation, any comments received, and other information. The street
address for the Docket Office (phone: 800-647-5527) is in the ADDRESSES
section. Comments will be available in the AD docket shortly after
receipt.
FOR FURTHER INFORMATION CONTACT: Alan Pohl, Aerospace Engineer,
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office,
1601 Lind Avenue SW., Renton, Washington 98057-3356; phone: (425) 917-
6450; fax: (425) 917-6590; email: [email protected].
SUPPLEMENTARY INFORMATION:
Comments Invited
We invite you to send any written relevant data, views, or
arguments about this proposed AD. Send your comments to an address
listed under the ADDRESSES section. Include ``Docket No. FAA-2012-0645;
Directorate Identifier 2011-NM-052-AD'' at the beginning of your
comments. We specifically invite comments on the overall regulatory,
economic, environmental, and energy aspects of this proposed AD. We
will consider all comments received by the closing date and may amend
this proposed AD because of those comments.
We will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We
will also post a report summarizing each substantive verbal contact we
receive about this proposed AD.
Discussion
On April 9, 1999, we issued AD 99-08-23, Amendment 39-11132 (64 FR
19879, April 23, 1999), for all The Boeing Company Model 737-100, -200,
-200C, -300, -400, and -500 series airplanes. That AD requires
repetitive inspections of the web of the aft pressure bulkhead at body
station 1016 at the aft fastener row attachment to the ``Y'' chord; and
corrective actions, if necessary. That AD resulted from reports of
fatigue cracking found at that location on The Boeing Company Model 737
series airplanes. We issued that AD to detect and correct such fatigue
cracking, which could result in rapid decompression of the fuselage.
Actions Since Existing AD Was Issued
Since we issued AD 99-08-23, Amendment 39-11132 (64 FR 19879, April
23, 1999), we have received reports that cracks have been found in four
general areas of the aft pressure bulkhead: In the web at the web-to-
``Y'' chord interface, in the web at the outer circumferential tear
strap, in the web near the dome cap, and in the ``Z'' stiffeners near
the dome cap. Cracks have been reported in these new areas on airplanes
that have accumulated between 21,246 and 68,000 total flight cycles,
and between 17,500 and 61,000 total flight hours.
[[Page 38548]]
Relevant Service Information
We reviewed Boeing Alert Service Bulletin 737-53A1214, Revision 4,
dated December 16, 2011. The service information describes procedures
and compliance times for various inspections for discrepancies
(including cracking, misdrilled fastener holes, elongated fastener
holes, corrosion, oil-cans, and existing repairs) at the aft pressure
bulkhead, and related investigative and corrective actions if
necessary, as follows:
Repetitive detailed and low frequency eddy current (LFEC)
inspections of the aft side of the upper bulkhead web, or detailed and
high frequency eddy current (HFEC) inspections from the forward side of
the bulkhead, to detect cracks, incorrectly drilled fastener holes, or
elongated fastener holes; and related investigative actions, including
HFEC and detailed inspections to detect additional cracks, incorrectly
drilled fastener holes, or elongated fastener holes on the section of
the web of the forward side of the bulkhead.
Repetitive detailed, surface HFEC, and subsurface LFEC
inspections to detect cracks, incorrectly drilled fastener holes, or
elongated fastener holes of the lower bulkhead web from the forward or
aft side of the bulkhead.
A one-time LFEC inspection to detect cracks on the aft
side of the bulkhead of the web located under the outer circumferential
tear strap, or a one-time HFEC inspection to detect cracks from the
forward side of the bulkhead of the web located under the outer
circumferential tear strap.
A detailed inspection from the aft side of the bulkhead
for oil-canning, and related investigative actions. The related
investigative actions include detailed and HFEC inspections for cracks,
and a measurement of the depth and width of the oil-can. For airplanes
on which oil-cans are found within limits, the service information
specifies an option of doing repetitive detailed and HFEC inspections
for cracks of the oil-canning and eventual repair. Doing the repair
terminates the repetitive inspections.
Repetitive eddy current inspections to detect cracks of
the dome cap at the center of the bulkhead.
Repetitive HFEC inspections to detect cracks of the ``Z''
stiffener flanges at the dome cap in the center of the bulkhead.
A detailed inspection of the bulkhead web and of the
stiffeners for existing repairs; and, depending on the findings,
repetitive HFEC or LFEC inspections of the web for cracking;
replacement of existing repairs with new repairs, and damage tolerance
inspections.
The corrective actions include repairing discrepancies
(including cracking, misdrilled fastener holes, elongated fastener
holes, corrosion, oil-cans, and existing repairs), or for certain
discrepancies, contacting Boeing for repair instructions.
The initial compliance times vary depending on inspection
type and area. The earliest initial inspection is within 375 flight
cycles after the effective date of this AD. The latest initial
inspection is within 6,000 flight cycles or 24 months after the
effective date of this AD, whichever occurs first.
The compliance times for the option, for airplanes on which oil-
cans are found within limits, of doing repetitive detailed and HFEC
inspections for cracks of the oil-canning and eventual repair are as
follows: The initial inspections are done before further flight. The
repetitive interval is 1,200 flight cycles. The repair must be done
within 12,000 flight cycles after the oil-can was found.
The repetitive inspections range from intervals not to exceed 6,000
flight cycles to intervals not to exceed 12,000 flight cycles,
depending on the inspection type and area.
FAA's Determination
We are proposing this AD because we evaluated all the relevant
information and determined the unsafe condition described previously is
likely to exist or develop in other products of the same type design.
Proposed AD Requirements
This proposed AD would retain all requirements of AD 99-08-23,
Amendment 39-11132 (64 FR 19879, April 23, 1999). This proposed AD
would also require accomplishing the actions specified in the service
information described previously, except as discussed under
``Differences Between the Proposed AD and the Service Information.''
Changes to Existing AD
This proposed AD would retain all requirements of AD 99-08-23,
Amendment 39-11132 (64 FR 19879, April 23, 1999). Since AD 99-08-23 was
issued, the AD format has been revised, and certain paragraphs have
been rearranged. As a result, the corresponding paragraph identifiers
have changed in this proposed AD, as listed in the following table:
Revised Paragraph Identifiers
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Requirement in AD 99-08-23,
Amendment 39-11132 (64 FR 19879, Corresponding requirement in this
April 23, 1999) proposed AD
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paragraph (a) paragraph (g)
paragraph (b) paragraph (h)
paragraph (c) paragraph (i)
paragraph (d) paragraph (j)
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Boeing Commercial Airplanes has received an Organization
Designation Authorization (ODA). We have revised this proposed AD to
delegate the authority to approve an alternative method of compliance
for any repair required by this proposed AD to the Boeing Commercial
Airplanes ODA rather than a Designated Engineering Representative
(DER).
We have revised the date of the document specified in paragraph
(j)(1) of this proposed AD (which is a restatement of paragraph (d)(1)
of AD 99-08-23, Amendment 39-11132 (64 FR 19879, April 23, 1999)), to
November 5, 1995, as specified in the ``Incorporation of Reference''
paragraph of AD 99-08-23 (paragraph (g) of AD 99-08-23).
Differences Between the Proposed AD and the Service Information
Boeing Alert Service Bulletin 737-53A1214, Revision 4, dated
December 16, 2011, specifies to contact the manufacturer for
instructions on how to repair certain conditions, but this proposed AD
would require repairing those conditions in one of the following ways:
In accordance with a method that we approve; or
Using data that meet the certification basis of the
airplane, and that have been approved by the Boeing Commercial
Airplanes Organization Designation Authorization (ODA) whom we have
authorized to make those findings.
Costs of Compliance
We estimate that this proposed AD affects 566 airplanes of U.S.
registry. We estimate the following costs to comply with this proposed
AD:
[[Page 38549]]
Estimated Costs
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Cost on U.S.
Action Labor cost Parts cost Cost per product operators
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LFEC [retained actions from AD 99- 8 work-hours x $85 $0 $680............... $384,880.
08-23, Amendment 39-11132 (64 FR per hour = $680.
19879, April 23, 1999)].
Detailed visual inspection 2 work-hours x $85 0 $170............... $96,220.
[retained actions from AD 99- per hour = $170.
08[dash]23, Amendment 39-11132
(64 FR 19879, April 23, 1999)].
Detailed, HFEC, and LFEC Up to 60 0 $5,100 per $2,886,600 per
inspections of the web at the work[dash]hours x inspection cycle. inspection cycle.
``Y'' chord of the bulkhead, the $85 per hour =
web located under the outer $5,100 per
circumferential tear strap, the inspection cycle.
``Z'' stiffeners at the dome
cap, and existing repairs [new
proposed action].
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We estimate the following costs to do any necessary on-condition
inspections that would be required based on the results of the proposed
initial inspection. We have no way of determining the number of
aircraft that might need these inspections:
On-Condition Costs
----------------------------------------------------------------------------------------------------------------
Cost per
Action Labor cost Parts cost product
----------------------------------------------------------------------------------------------------------------
Detailed and HFEC inspections for 1 work-hour x $85 per hour = $85 $0 $85
oil[dash]canning.
LFEC or HFEC inspections for cracking......... 2 work-hours x $85 per hour = 0 170
$170.
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We have received no definitive data that would enable us to provide
cost estimates for the crack repairs specified in this proposed AD.
Authority for This Rulemaking
Title 49 of the United States Code specifies the FAA's authority to
issue rules on aviation safety. Subtitle I, Section 106, describes the
authority of the FAA Administrator. Subtitle VII, Aviation Programs,
describes in more detail the scope of the Agency's authority.
We are issuing this rulemaking under the authority described in
Subtitle VII, Part A, Subpart III, Section 44701, ``General
requirements.'' Under that section, Congress charges the FAA with
promoting safe flight of civil aircraft in air commerce by prescribing
regulations for practices, methods, and procedures the Administrator
finds necessary for safety in air commerce. This regulation is within
the scope of that authority because it addresses an unsafe condition
that is likely to exist or develop on products identified in this
rulemaking action.
Regulatory Findings
We have determined that this proposed AD would not have federalism
implications under Executive Order 13132. This proposed AD would not
have a substantial direct effect 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.
For the reasons discussed above, I certify that the 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),
(3) Will not affect intrastate aviation in Alaska, and
(4) 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.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
The Proposed Amendment
Accordingly, under the authority delegated to me by the
Administrator, the FAA proposes to amend 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. The FAA amends Sec. 39.13 by removing airworthiness directive
(AD) 99-08-23, Amendment 39-11132 (64 FR 19879, April 23, 1999), and
adding the following new AD:
The Boeing Company: Docket No. FAA-2012-0645; Directorate Identifier
2011-NM-052-AD.
(a) Comments Due Date
The FAA must receive comments on this AD action by August 13,
2012.
(b) Affected ADs
This AD supersedes AD 99-08-23, Amendment 39-11132 (64 FR 19879,
April 23, 1999).
(c) Applicability
This AD applies to all The Boeing Company Model 737-100, -200, -
200C, -300, -400, and -500 series airplanes; certificated in any
category.
(d) Subject
Joint Aircraft System Component (JASC)/Air Transport Association
(ATA) of America Code 53, Fuselage.
(e) Unsafe Condition
This AD was prompted by several reports of fatigue cracks in the
aft pressure bulkhead. We are issuing this AD to detect and correct
such fatigue cracking, which could result in rapid decompression of
the fuselage.
(f) Compliance
Comply with this AD within the compliance times specified,
unless already done.
(g) Retained Initial Inspection
This paragraph restates the initial inspection required by
paragraph (a) of AD 99-08-23, Amendment 39-11132 (64 FR 19879, April
23, 1999). Perform either inspection specified by paragraph (g)(1)
or
[[Page 38550]]
(g)(2) of this AD at the time specified in paragraph (h) of this AD.
(1) Perform a low frequency eddy current (LFEC) inspection from
the aft side of the aft pressure bulkhead to detect discrepancies
(including cracking, misdrilled fastener holes, and corrosion) of
the web of the upper section of the aft pressure bulkhead at body
station 1016 at the aft fastener row attachment to the ``Y'' chord,
from stringer 15 left to stringer 15 right, in accordance with
Boeing 737 Nondestructive Test Manual D6-37239, Part 6, Section 53-
10-54, dated December 5, 1998.
(2) Perform a detailed visual inspection of the aft fastener row
attachment to the ``Y'' chord from the forward side of the aft
pressure bulkhead to detect discrepancies (including cracking,
misdrilled fastener holes, and corrosion) of the entire web of the
aft pressure bulkhead at body station 1016.
(h) Retained Compliance Times
This paragraph restates the compliance times specified in
paragraph (b) of AD 99-08-23, Amendment 39-11132 (64 FR 19879, April
23, 1999). Perform the inspection required by paragraph (g) of this
AD at the time specified in paragraph (h)(1), (h)(2), or (h)(3) of
this AD, as applicable.
(1) For airplanes that have accumulated 40,000 or more total
flight cycles as of May 10, 1999 (the effective date of AD 99-08-23,
Amendment 39-11132 (64 FR 19879, April 23, 1999)): Inspect within
375 flight cycles or 60 days after May 10, 1999, whichever occurs
later.
(2) For airplanes that have accumulated 25,000 or more total
flight cycles and fewer than 40,000 total flight cycles as of May
10, 1999 (the effective date of AD 99-08-23, Amendment 39-11132 (64
FR 19879, April 23, 1999)): Inspect within 750 flight cycles or 90
days after May 10, 1999, whichever occurs later.
(3) For airplanes that have accumulated fewer than 25,000 total
flight cycles as of May 10, 1999 (the effective date of AD 99-08-23,
Amendment 39-11132 (64 FR 19879, April 23, 1999)): Inspect prior to
the accumulation of 25,750 total flight cycles.
(i) Retained Repetitive Inspections
This paragraph restates the repetitive inspections required by
paragraph (c) of AD 99-08-23, Amendment 39-11132 (64 FR 19879, April
23, 1999). Within 1,200 flight cycles after performing the initial
inspection required by paragraph (g) of this AD, and thereafter at
intervals not to exceed 1,200 flight cycles: Perform either
inspection specified by paragraph (g)(1) or (g)(2) of this AD.
(j) Retained Corrective Actions
This paragraph restates the corrective actions required by
paragraph (d) of AD 99-08-23, Amendment 39-11132 (64 FR 19879, April
23, 1999). If any discrepancy is detected during any inspection
required by paragraph (g), (h), or (i) of this AD: Prior to further
flight, accomplish the actions specified by paragraphs (j)(1) and
(j)(3) of this AD, and paragraph (j)(2) of this AD, if applicable.
(1) Perform a high frequency eddy current inspection from the
forward side of the bulkhead to detect cracking of the web at the
``Y'' chord attachment, around the entire periphery of the ``Y''
chord, in accordance with Boeing 737 Nondestructive Test Manual D6-
37239, Part 6, Section 51-00-00, Figure 23, dated November 5, 1995.
(2) If the most recent inspection performed in accordance with
paragraph (g) of this AD was not a detailed visual inspection:
Accomplish the actions specified by paragraph (g)(2) of this AD. If
the inspection was a detailed visual inspection, it is not necessary
to repeat that inspection prior to further flight.
(3) Repair any discrepancy such as cracking or corrosion or
misdrilled fastener holes using a method approved in accordance with
the procedures specified in paragraph (u) of this AD.
(k) New Requirements: Inspections of the Web at the ``Y'' Chord Upper
Bulkhead From S-15L to S-15R
At the later of the times specified in paragraphs (k)(1) and
(k)(2) of this AD: Do detailed and LFEC inspections of the aft side
of the bulkhead web, or do detailed and HFEC inspections from the
forward side of the bulkhead, and do all applicable related
investigative and corrective actions; in accordance with Part 1 of
the Accomplishment Instructions of Boeing Alert Service Bulletin
737-53A1214, Revision 4, dated December 16, 2011, except as required
by paragraphs (r)(1) and (r)(3) of this AD. Inspect for cracks,
incorrectly drilled fastener holes, and elongated fastener holes. Do
all applicable related investigative and corrective actions before
further flight. Repeat the inspections at the applicable times
specified in table 1 of paragraph 1.E., ``Compliance,'' of Boeing
Alert Service Bulletin 737-53A1214, Revision 4, dated December 16,
2011.
(1) Prior to the accumulation of 25,000 total flight cycles.
(2) Except as required by paragraphs (r)(2) and (r)(4) of this
AD, at the later of the times specified in the ``Compliance Time''
column in table 1 of paragraph 1.E., ``Compliance,'' of Boeing Alert
Service Bulletin 737-53A1214, Revision 4, dated December 16, 2011.
(l) New Requirements: Inspections of the Web at the ``Y'' Chord in the
Lower Bulkhead From S-15L to S-15R
Except as required by paragraphs (r)(2) and (r)(5) of this AD,
at the applicable time specified in table 2 of paragraph 1.E.,
``Compliance,'' of Boeing Alert Service Bulletin 737-53A1214,
Revision 4, dated December 16, 2011: Do detailed and eddy current
inspections of the web from the forward or aft side of the bulkhead
for cracks, incorrectly drilled fasteners, and elongated fasteners,
in accordance with Part III of the Accomplishment Instructions of
Boeing Alert Service Bulletin 737-53A1214, Revision 4, dated
December 16, 2011, except as required by paragraphs (r)(1) and
(r)(3) of this AD. If any crack, incorrectly drilled fastener,
elongated fastener, or corrosion is found, before further flight,
repair the web using a method approved in accordance with the
procedures specified in paragraph (u) of this AD. Repeat the
inspections at the applicable times specified in table 2 of
paragraph 1.E., ``Compliance,'' of Boeing Alert Service Bulletin
737-53A1214, Revision 4, dated December 16, 2011.
(m) New Requirements: One-Time Inspection Under the Tear Strap
Except as required by paragraphs (r)(2) and (r)(5) of this AD,
at the applicable time specified in table 3 of paragraph 1.E.,
``Compliance,'' of Boeing Alert Service Bulletin 737-53A1214,
Revision 4, dated December 16, 2011: Do a one-time LFEC inspection
for cracks on the aft side of the bulkhead of the web located under
the outer circumferential tear strap, or do a one-time HFEC
inspection for cracks from the forward side of the bulkhead of the
web located under the outer circumferential tear strap, in
accordance with Part II of the Accomplishment Instructions of Boeing
Alert Service Bulletin 737-53A1214, Revision 4, dated December 16,
2011, except as required by paragraph (r)(1) of this AD. If any
cracking is found, before further flight, repair the bulkhead using
a method approved in accordance with the procedures specified in
paragraph (u) of this AD.
(n) New Requirements: Inspection for Oil-Canning
Except as required by paragraph (r)(2) of this AD, at the
applicable time specified in table 4 of paragraph 1.E.,
``Compliance,'' of Boeing Alert Service Bulletin 737-53A1214,
Revision 4, dated December 16, 2011: Do a detailed inspection from
the aft side of the bulkhead for oil-canning and do all applicable
related investigative and corrective actions, in accordance with
Part II of the Accomplishment Instructions of Boeing Alert Service
Bulletin 737-53A1214, Revision 4, dated December 16, 2011, except as
required by paragraph (r)(1) of this AD. Do all related
investigative and corrective actions before further flight.
Thereafter, repeat the inspection at the applicable times specified
in table 4 of paragraph 1.E., ``Compliance,'' of Boeing Alert
Service Bulletin 737-53A1214, Revision 4, dated December 16, 2011.
For oil-cans found within the limits specified in Part II of the
Accomplishment Instructions of Boeing Alert Service Bulletin 737-
53A1214, Revision 4, dated December 16, 2011: In lieu of installing
the repair before further flight, at the applicable times specified
in table 4 of paragraph 1.E., ``Compliance,'' of Boeing Alert
Service Bulletin 737-53A1214, Revision 4, dated December 16, 2011,
do initial and repetitive detailed and HFEC inspections for cracks
of the oil-canning and install the repair, in accordance with the
Accomplishment Instructions of Boeing Alert Service Bulletin 737-
53A1214, Revision 4, dated December 16, 2011. If any crack is found,
before further flight, repair the cracking using a method approved
in accordance with the procedures specified in paragraph (u) of this
AD. Installing the repair terminates the repetitive inspections for
cracks.
[[Page 38551]]
(o) New Requirements: Inspection of the Dome Cap at the Center of the
Bulkhead
Except as required by paragraphs (r)(2) and (r)(5) of this AD,
at the applicable time specified in table 5 of paragraph 1.E.,
``Compliance,'' of Boeing Alert Service Bulletin 737-53A1214,
Revision 4, dated December 16, 2011: Do an eddy current inspection
to detect any cracking of the dome cap at the center of the
bulkhead, and do all applicable corrective actions, in accordance
with Part IV of the Accomplishment Instructions of Boeing Alert
Service Bulletin 737-53A1214, Revision 4, dated December 16, 2011.
Do all corrective actions before further flight. Repeat the
inspection at the times specified in table 5 of paragraph 1.E.,
``Compliance,'' of Boeing Alert Service Bulletin 737-53A1214,
Revision 4, dated December 16, 2011.
(p) New Requirements: Inspection of the Forward Flange of the ``Z''
Stiffeners at the Dome Cap
Except as required by paragraphs (r)(2) and (r)(5) of this AD,
at the applicable time specified in table 6 of paragraph 1.E.,
``Compliance,'' of Boeing Alert Service Bulletin 737-53A1214,
Revision 4, dated December 16, 2011: Do an HFEC inspection to detect
any cracking of the ``Z'' stiffener flanges at the dome cap in the
center of the bulkhead, in accordance with Part V of the
Accomplishment Instructions of Boeing Alert Service Bulletin 737-
53A1214, Revision 4, dated December 16, 2011, except as required by
paragraph (r)(1) of this AD. If any crack is found, before further
flight, repair the flanges using a method approved in accordance
with the procedures specified in paragraph (u) of this AD. Repeat
the inspection at the applicable times specified in table 6 of
paragraph 1.E., ``Compliance,'' of Boeing Alert Service Bulletin
737-53A1214, Revision 4, dated December 16, 2011.
(q) New Requirement: Inspection for Existing Repairs on the Bulkhead
Except as required by paragraph (r)(2) of this AD, at the
applicable time specified in table 7 of paragraph 1.E.,
``Compliance,'' of Boeing Alert Service Bulletin 737-53A1214,
Revision 4, dated December 16, 2011: Do a detailed inspection of the
bulkhead web and stiffeners for existing repairs, in accordance with
Part VI of the Accomplishment Instructions of Boeing Alert Service
Bulletin 737-53A1214, Revision 4, dated December 16, 2011, except as
required by paragraph (r)(1) of this AD.
(1) If any repair identified in the ``Condition'' column of
table 8 of paragraph 1.E., ``Compliance,'' of Boeing Alert Service
Bulletin 737-53A1214, Revision 4, dated December 16, 2011, is found
and the ``Reference'' column refers to Appendix A, B, C, or D of
that service bulletin: At the applicable times specified in table 8
of paragraph 1.E., ``Compliance,'' of Boeing Alert Service Bulletin
737-53A1214, Revision 4, dated December 16, 2011, except as required
by paragraph (r)(2) of this AD, do a HFEC inspection or a LFEC
inspection of the web for cracking, in accordance with Appendix A,
B, C, or D, as applicable, of Boeing Alert Service Bulletin 737-
53A1214, Revision 4, dated December 16, 2011. If any cracking is
found, before further flight, repair using a method approved in
accordance with the procedures specified in paragraph (u) of this
AD. Repeat the inspections, thereafter, at the applicable intervals
specified in table 8 of paragraph 1.E., ``Compliance,'' of Boeing
Alert Service Bulletin 737-53A1214, Revision 4, dated December 16,
2011.
(2) If any repair identified in the ``Condition'' column of
table 8 of paragraph 1.E., ``Compliance,'' of Boeing Alert Service
Bulletin 737-53A1214, Revision 4, dated December 16, 2011, is found
and the ``Reference'' column refers to Appendix E of that service
bulletin: At the applicable times specified in table 8 of paragraph
1.E., ``Compliance,'' of Boeing Alert Service Bulletin 737-53A1214,
Revision 4, dated December 16, 2011, except as required by paragraph
(r)(2) of this AD, remove the repair and replace with a new repair,
in accordance with Appendix E of Boeing Alert Service Bulletin 737-
53A1214, Revision 4, dated December 16, 2011.
(3) If any non-SRM (structural repair manual) repair is found
and the repair does not have FAA-approved damage tolerance
inspections, except as required by paragraph (r)(2) of this AD, at
the applicable time specified in table 7 of Paragraph 1.E.,
``Compliance,'' of Boeing Alert Service Bulletin 737-53A1214,
Revision 4, dated December 16, 2011: Contact the Boeing Commercial
Airplanes Organization Designation Authorization (ODA) that has been
authorized by the Manager, Seattle ACO, for damage tolerance
inspections. Do those damage tolerance inspections at the times
given using a method approved in accordance with the procedures
specified in paragraph (u) of this AD.
(r) Exceptions to the Service Bulletin
(1) Where Boeing Alert Service Bulletin 737-53A1214, Revision 4,
dated December 16, 2011, specifies to contact Boeing for repair
instructions: Before further flight, repair using a method approved
in accordance with the procedures specified in paragraph (u) of this
AD.
(2) Where Boeing Alert Service Bulletin 737-53A1214, Revision 4,
dated December 16, 2011, specifies a compliance time ``after the
date of Revision 1 to this service bulletin,'' ``from the date of
Revision 3 of this service bulletin,'' ``after the date of Revision
3 to this service bulletin,'' or ``of the effective date of AD 99-
08-23,'' this AD requires compliance within the specified compliance
time after the effective date of this AD.
(3) Access and restoration procedures specified in the
Accomplishment Instructions of Boeing Alert Service Bulletin 737-
53A1214, Revision 4, dated December 16, 2011, are not required by
this AD. Operators may do those procedures following their
maintenance practices.
(4) Where table 1 of paragraph 1.E., ``Compliance'' of Boeing
Alert Service Bulletin 737-53A1214, Revision 4, dated December 16,
2011, specifies a compliance time relative to actions done ``in
accordance with paragraph (a)(2) of AD 99-08-23,'' this AD requires
compliance within the specified compliance time relative to actions
specified in paragraph (g)(2) of this AD.
(5) Where the Condition columns in tables 2, 3, 5, and 6 of
paragraph 1.E., ``Compliance,'' of Boeing Alert Service Bulletin
737-53A1214, Revision 4, dated December 16, 2011, refer to total
flight cycles, this AD applies to the airplanes with the specified
total flight cycles as of the effective date of this AD.
(s) Terminating Action
Accomplishment of the requirements of paragraphs (k) through (q)
of this AD terminates the requirements of paragraphs (g) through (j)
of this AD.
(t) Credit for Previous Actions
This paragraph provides credit for the actions required by
paragraphs (k) through (s) of this AD, if the actions were performed
before the effective date of this AD using the service bulletins
specified in paragraphs (t)(1) through (t)(4) of this AD.
(1) Boeing Alert Service Bulletin 737-53A1214, dated June 17,
1999.
(2) Boeing Alert Service Bulletin 737-53A1214, Revision 1, dated
June 22, 2000.
(3) Boeing Alert Service Bulletin 737-53A1214, Revision 2, dated
May 24, 2001.
(4) Boeing Alert Service Bulletin 737-53A1214, Revision 3, dated
January 19, 2011.
(u) Alternative Methods of Compliance (AMOCs)
(1) The Manager, Seattle ACO, FAA, has the authority to approve
AMOCs for this AD, if requested using the procedures found in 14 CFR
39.19. In accordance with 14 CFR 39.19, send your request to your
principal inspector or local Flight Standards District Office, as
appropriate. If sending information directly to the manager of the
ACO, send it to the attention of the person identified in the
Related Information section of this AD. Information may be emailed
to: [email protected].
(2) Before using any approved AMOC, notify your appropriate
principal inspector, or lacking a principal inspector, the manager
of the local flight standards district office/certificate holding
district office.
(3) An AMOC that provides an acceptable level of safety may be
used for any repair required by this AD if it is approved by the
Boeing Commercial Airplanes Organization Designation Authorization
(ODA) that has been authorized by the Manager, Seattle ACO to make
those findings. For a repair method to be approved, the repair must
meet the certification basis of the airplane, and the approval must
specifically refer to this AD.
(4) AMOCs approved previously in accordance with AD 99-08-23,
Amendment 39-11132 (64 FR 19879, April 23, 1999), are approved as
AMOCs for the corresponding provisions of this AD.
(v) Related Information
(1) For more information about this AD, contact Alan Pohl,
Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft
Certification Office, 1601 Lind Avenue SW., Renton, Washington
98057-3356; phone: (425) 917-6440; fax: (425) 917-6590; email:
[email protected].
[[Page 38552]]
(2) For service information identified in this proposed AD,
contact Boeing Commercial Airplanes, Attention: Data & Services
Management, P.O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207;
telephone 206-544-5000, extension 1; fax 206-766-5680; Internet
https://www.myboeingfleet.com. You may review copies of the
referenced service information at the FAA, Transport Airplane
Directorate, 1601 Lind Avenue SW., Renton, Washington. For
information on the availability of this material at the FAA, call
425-227-1221.
Issued in Renton, Washington, on June 18, 2012.
John P. Piccola,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 2012-15601 Filed 6-27-12; 8:45 am]
BILLING CODE 4910-13-P