[Federal Register Volume 76, Number 151 (Friday, August 5, 2011)]
[Proposed Rules]
[Pages 47522-47527]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2011-19904]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2011-0722; Directorate Identifier 2010-NM-262-AD]
RIN 2120-AA64
Airworthiness Directives; The Boeing Company Model 737-100, -200,
-200C, -300, -400, and -500 Series 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 certain Model 737-100 and -200 series airplanes.
The existing AD currently requires various inspections for cracks in
the outboard chord of the frame at body station (BS) 727 and in the
outboard chord of stringer (S) 18A, and repair or replacement of
cracked parts. Since we issued that AD, there have been several reports
of fatigue cracking in the frame outboard chord at BS 727 and in the
radius of the auxiliary chord on airplanes that were not affected by
the existing AD. This proposed AD would add airplanes to the
applicability statement in the existing AD and add inspections for
cracks in the BS 727 frame outboard chords and the radius of the
auxiliary chord, for certain airplanes. This proposed AD would also
remove the inspections of the outboard chord of S-18A required by the
existing AD. We are proposing this AD to detect and correct fatigue
cracking of the outboard and auxiliary chords, which
[[Page 47523]]
could result in reduced structural integrity of the outboard chord and
consequent rapid decompression of the airplane.
DATES: We must receive comments on this proposed AD by September 19,
2011.
ADDRESSES: You may send comments 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 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; e-mail [email protected]; 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; e-mail [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-2011-0722;
Directorate Identifier 2010-NM-262-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 June 5, 1995, we issued AD 95-12-17, amendment 39-9268 (60 FR
36981, July 19, 1995), for certain Model 737-100 and -200 series
airplanes. That AD requires various inspections for cracks in the
outboard chord of the frame at body station (BS) 727 and in the
outboard chord of stringer (S) 18A, and repair or replacement of
cracked parts. That AD resulted from reports of fatigue cracks in those
outboard chords. We issued that AD to prevent such fatigue cracking,
which could result in reduced structural integrity of the outboard
chords, and subsequent rapid decompression of the airplane.
Actions Since Existing AD Was Issued
Since we issued AD 95-12-17, we have received several reports of
fatigue cracking in the frame outboard chord at BS 727 and in the
radius of the auxiliary chord. The cracking in the chords occurred on
airplanes that had accumulated between 20,000 and 52,000 total flight
cycles, and between 27,000 and 74,000 total flight hours. The cracking
in the auxiliary chord occurred on airplanes that had accumulated
between 46,000 and 85,000 total flight cycles, and between 41,000 and
64,000 total flight hours. This cracking is caused by fatigue. The
airplanes that are affected by AD 95-12-17 were produced with outboard
chords at BS 727 made of 7075-T6 aluminum; subsequent airplanes were
produced with outboard chords made of 7075-T73 aluminum.
In addition, we have determined that the inspections of the
outboard chord of S-18A required by the existing AD are no longer
necessary. The new inspections (described below) will decrease the
probability of cracks in the frame at BS 727 where S-18A is attached.
Relevant Service Information
We reviewed Boeing Alert Service Bulletin 737-53A1166, Revision 2,
dated May 25, 2006. The existing AD refers to Boeing Alert Service
Bulletin 737-53A1166, dated June 30, 1994; and Boeing Service Bulletin
737-53A1166, Revision 1, dated May 25, 1995; for accomplishing the
required actions. Revision 1 of this service bulletin was issued to
include airplanes having 7075-T73 frame outboard chords. Revision 2 of
this service bulletin expands the effectivity in Revision 1 of this
service bulletin, and adds inspections for cracks of the 7075-T73 frame
outboard chord and in the radius of the auxiliary chord, and repair or
replacement if necessary.
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 certain requirements of AD 95-12-17.
This proposed AD would add airplanes to the applicability statement in
the existing AD. This proposed AD would also remove the inspections of
the outboard chord of S-18A required by the existing AD, and add
inspections for cracks in the BS 727 frame outboard chords and the
radius of the auxiliary chord, for certain airplanes. This proposed AD
would require accomplishing the actions specified in the service
information described previously, except as discussed under
``Difference Between the Proposed AD and the Service Information.''
Change to Existing AD
Since AD 95-12-17 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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Corresponding
Requirement in AD 95-12-17 requirement in
this proposed AD
------------------------------------------------------------------------
paragraph (a)....................................... paragraph (g)
paragraph (b)....................................... paragraph (h)
paragraph (c)....................................... paragraph (i)
paragraph (d)....................................... paragraph (j)
paragraph (e)....................................... removed
paragraph (f)....................................... paragraph (k)
paragraph (g)....................................... paragraph (l)
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[[Page 47524]]
Difference Between the Proposed AD and the Service Information
Boeing Alert Service Bulletin 737-53A1166, Revision 2, dated May
25, 2006, specifies contacting the manufacturer for instructions on how
to repair a certain condition, but this AD requires repairing that
condition in one of the following ways:
Using a method that we approve; or
Using data that meet the certification basis of the
airplane, and that have been approved by an Authorized Representative
for the Boeing Commercial Airplanes Organization Designation
Authorization whom we have authorized to make those findings.
Costs of Compliance
We estimate that this proposed AD affects 574 airplanes of U.S.
registry.
We estimate the following costs to comply with this proposed AD:
Estimated Costs
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Cost per Cost on U.S. Number of U.S.
Action Labor cost Parts cost product operators airplanes
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Various inspections (retained 4 work-hours x $0 $340 per $100,640 per 296
actions from existing AD). $85 per hour = inspection inspection
$340 per cycle. cycle.
inspection
cycle.
Ultrasonic inspection (new 13 work-hours x 0 1,105 per 634,270 per 574
proposed action). $85 per hour = inspection inspection
$1,105 per cycle. cycle.
inspection
cycle.
Detailed and HFEC inspections 13 work-hours x 0 1,105 per 634,270 per 574
(new proposed actions). $85 per hour = inspection inspection
$1,105 per cycle. cycle.
inspection
cycle.
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We estimate the following costs to do any necessary repairs that
would be required based on the results of the proposed inspections. We
have no way of determining the number of aircraft that might need these
repairs:
On-Condition Costs
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Cost per
Action Labor cost Parts cost product
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Optional modification (retained action from 50 work-hours x $85 per hour = $3,680 $7,930
existing AD). $4,250.
Repair of cracking of the outboard chord frame 514 work-hours x $85 per hour = 13,586 57,276
$42,690.
Time-limited repair cracking of the outboard 63 work-hours x $85 per hour = 2,732 8,087
chord frame. $5,355.
Repair of cracking of the outboard chord...... 49 work-hours x $85 per hour = 4,255 8,420
$4,165.
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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) 95-12-17, Amendment 39-9268 (60 FR 36981, July 19, 1995), and
adding the following new AD:
The Boeing Company: Docket No. FAA-2011-0722; Directorate Identifier
2010-NM-262-AD.
Comments Due Date
(a) The FAA must receive comments on this AD action by September
19, 2011.
[[Page 47525]]
Affected ADs
(b) This AD supersedes AD 95-12-17, Amendment 39-9268.
Applicability
(c) This AD applies to all The Boeing Company Model 737-100, -
200, -200C, -300, -400, and -500 series airplanes, certificated in
any category.
Subject
(d) Joint Aircraft System Component (JASC)/Air Transport
Association (ATA) of America Code 53, Fuselage.
Unsafe Condition
(e) This AD was prompted by several reports of fatigue cracking
in the frame outboard chord at body station (BS) 727, and cracks in
the radius of the auxiliary chord on airplanes that were not
affected by the existing AD. We are issuing this AD to detect and
correct fatigue cracking of the outboard and auxiliary chords, which
could result in reduced structural integrity of the outboard chord
and consequent rapid decompression of the airplane.
Compliance
(f) Comply with this AD within the compliance times specified,
unless already done.
Restatement of Certain Requirements of AD 95-12-17 With Revised Service
Information: Repetitive Inspections and Repair or Replacement
(g) For Model 737-100 and -200 series airplanes on which the BS
727 frame upper outboard chord has been replaced in accordance with
Boeing Service Bulletin 737-53-1088: Prior to the accumulation of
30,000 total flight cycles since replacement of the upper outboard
chord, or within 4,500 flight cycles after August 18, 1995 (the
effective date of AD 95-12-17), whichever occurs later, perform
close visual, pulse echo shear wave (PESW), and high frequency eddy
current (HFEC) inspections to detect cracks in the outboard chord of
the frame at BS 727, in accordance with Part I of the Accomplishment
Instructions of Boeing Alert Service Bulletin 737-53A1166, dated
June 30, 1994; Boeing Service Bulletin 737-53A1166, Revision 1,
dated May 25, 1995; or Boeing Alert Service Bulletin 737-53A1166,
Revision 2, dated May 25, 2006; as applicable. As of the effective
date of this AD use only Revision 2 of this service bulletin.
(h) For Model 737-100 and -200 series airplanes on which the BS
727 frame upper outboard chord has been replaced in accordance with
Boeing Service Bulletin 737-53-1088: Repeat the inspections required
by paragraph (g) of this AD at the time specified in paragraphs
(h)(1), (h)(2), (h)(3), and (h)(4) of this AD, as applicable, until
the optional terminating action described in paragraph (l) of this
AD is accomplished.
(1) If, at the time of the most recent inspection required by
paragraph (g) or (h) of this AD, the airplane has accumulated 27,000
or more total flight cycles, but fewer than 50,000 total flight
cycles since the replacement of the outboard chord: Perform the next
inspection within 15,000 flight cycles. Repeat the inspection
thereafter at intervals not to exceed 15,000 flight cycles until the
airplane has accumulated 50,000 or more total flight cycles since
the replacement of the outboard chord. Do the inspections required
by paragraph (h)(2) of this AD at the time specified.
(2) If, at the time of the most recent inspection required by
paragraph (g) or (h) of this AD, the airplane has accumulated 50,000
or more total flight cycles, but fewer than 60,000 total flight
cycles, since the replacement of the outboard chord: Perform the
next inspection within 7,500 flight cycles. Repeat the inspection
thereafter at intervals not to exceed 7,500 flight cycles until the
airplane has accumulated 60,000 or more total flight cycles since
the replacement of the outboard chord. Do the inspections required
by paragraph (h)(3) of this AD at the time specified.
(3) If, at the time of the most recent inspection required by
paragraph (g) or (h) of this AD, the airplane has accumulated 60,000
or more total flight cycles, but fewer than 70,000 total flight
cycles, since the replacement of the outboard chord: Perform the
next inspection within 5,000 flight cycles. Repeat the inspection
thereafter at intervals not to exceed 5,000 flight cycles until the
airplane has accumulated 70,000 or more total flight cycles since
the replacement of the outboard chord. Do the inspections required
by paragraph (h)(4) of this AD at the time specified.
(4) If, at the time of the most recent inspection required by
paragraph (g) or (h) of this AD, the airplane has accumulated 70,000
or more total flight cycles since replacement of the outboard chord:
Perform the next inspection within 3,000 flight cycles. Repeat the
inspection thereafter at intervals not to exceed 3,000 flight
cycles.
(i) For Model 737-100 and -200 series airplanes on which the BS
727 frame outboard chord has not been replaced, or on which only the
lower outboard chord has been replaced in accordance with Boeing
Service Bulletin 737-53-1088: Perform close visual, PESW, and HFEC
inspections to detect cracks in the outboard chord of the frame at
BS 727, in accordance with Part I of the Accomplishment Instructions
of Boeing Alert Service Bulletin 737-53A1166, dated June 30, 1994;
Boeing Service Bulletin 737-53A1166, Revision 1, dated May 25, 1995;
or Boeing Alert Service Bulletin 737-53A1166, Revision 2, dated May
25, 2006; as applicable. As of the effective date of this AD, use
only Revision 2 of this service bulletin. Perform these inspections
initially at the time specified in paragraph (i)(1), (i)(2), (i)(3),
or (i)(4), as applicable. Repeat these inspections thereafter at the
intervals specified in paragraph (j) of this AD.
(1) For airplanes that have accumulated 27,000 or more total
flight cycles, but fewer than 50,000 total flight cycles, as of
August 18, 1995: Inspect prior within 4,500 flight cycles after
August 18, 1995.
(2) For airplanes that have accumulated 50,000 or more total
flight cycles, but fewer than 60,000 total flight cycles, as of
August 18, 1995: Inspect prior to the accumulation of 2,500 flight
cycles after August 18, 1995.
(3) For airplanes that have accumulated 60,000 or more total
flight cycles, but fewer than 70,000 total flight cycles as of
August 18, 1995: Inspect prior to the accumulation of 1,500 flight
cycles after August 18, 1995.
(4) For airplanes that have accumulated 70,000 or more total
flight cycles as of August 18, 1995: Inspect prior to the
accumulation of 500 flight cycles or within 90 days after August 18,
1995, whichever occurs first.
(j) Repeat the inspections required by paragraph (i) of this AD
at the time specified in paragraphs (j)(1), (j)(2), (j)(3), and
(j)(4) of this AD, as applicable, until the optional terminating
action described in paragraph (l) of this AD is accomplished:
(1) If, at the time of the most recent inspection required by
paragraph (i) or (j) of this AD, the airplane has accumulated 27,000
or more total flight cycles, but fewer than 50,000 total flight
cycles: Perform the next inspection within 15,000 flight cycles.
Repeat the inspection thereafter at intervals not to exceed 15,000
flight cycles until the airplane has accumulated 50,000 or more
total flight cycles. Do the inspections required by paragraph (j)(2)
of this AD at the time specified.
(2) If, at the time of the most recent inspection required by
paragraph (i) or (j) of this AD, the airplane had accumulated 50,000
or more total flight cycles, but fewer than 60,000 total flight
cycles: Perform the next inspection within 7,500 flight cycles.
Repeat the inspection thereafter at intervals not to exceed 7,500
flight cycles until the airplane has accumulated 60,000 or more
total flight cycles. Do the inspections required by paragraph (j)(3)
of this AD at the time specified.
(3) If, at the time of the most recent inspection required by
paragraph (i) or (j) of this AD, the airplane had accumulated 60,000
or more total flight cycles, but fewer than 70,000 total flight
cycles: Perform the next inspection within 5,000 flight cycles.
Repeat the inspection thereafter at intervals not to exceed 5,000
flight cycles until the airplane has accumulated 70,000 or more
total flight cycles. Do the inspections required by paragraph (j)(4)
of this AD at the time specified.
(4) If, at the time of the most recent inspection required by
paragraph (i) or (j) of this AD, the airplane had accumulated 70,000
or more total flight cycles: Perform the next inspection within
3,000 flight cycles. Repeat the inspection thereafter at intervals
not to exceed 3,000 flight cycles.
(k) If any crack is found in the outboard chord of the frame at
BS 727 during any inspection required by paragraphs (g) through (j)
of this AD, accomplish paragraph (k)(1) or (k)(2) of this AD, as
applicable, in accordance with Boeing Alert Service Bulletin 737-
53A1166, dated June 30, 1994; Boeing Service Bulletin 737-53A1166,
Revision 1, dated May 25, 1995; or Boeing Alert Service Bulletin
737-53A1166, Revision 2, dated May 25, 2006; as applicable. As of
the effective date of this AD, use only Revision 2 of this service
bulletin.
(1) For any crack that extends from the forward edge of the
chord or from the forward fastener hole, but that does not
[[Page 47526]]
extend past the second fastener hole, accomplish either paragraph
(l)(1)(i) or (l)(1)(ii) of this AD. Thereafter, perform initial and
repetitive inspections in accordance with paragraphs (g) and (h) of
this AD.
(i) Prior to further flight, install the time limited repair.
Within 4,500 flight cycles or within 18 months after accomplishing
the time-limited repair, whichever occurs first, replace the
outboard chord. Or
(ii) Prior to further flight, replace the outboard chord.
Note 1: Boeing Alert Service Bulletin 737-53A1166, dated June
30, 1994; Boeing Service Bulletin 737-53A1166, Revision 1, dated May
25, 1995; and Boeing Alert Service Bulletin 737-53A1166, Revision 2,
dated May 25, 2006; refer to Boeing Service Bulletin 737-53-1088 as
an additional source of guidance for procedures to replace the
chord.
(2) For any crack that extends from the forward edge of the
chord, or from the forward fastener hole, and that extends past the
second fastener hole, prior to further flight, replace the outboard
chord in accordance with Boeing Alert Service Bulletin 737-53A1166,
dated June 30, 1994; Boeing Service Bulletin 737-53A1166, Revision
1, dated May 25, 1995; or Boeing Alert Service Bulletin 737-53A1166,
Revision 2, dated May 25, 2006; as applicable. As of the effective
date of this AD, use only Revision 2 of this service bulletin.
Thereafter, perform initial and repetitive inspections in accordance
with paragraphs (g) and (h) of this AD.
New Requirements of This AD: Repetitive Inspections/Repair or Replace
if Necessary
(l) For airplanes identified in table 5 of paragraph 1.E.,
``Compliance'' of Boeing Alert Service Bulletin 737-53A1166,
Revision 2, dated May 25, 2006: Before the accumulation of 27,000
total flight cycles, or within 5,000 flight cycles after the
effective date of this AD, whichever occurs later, do internal
detailed and HFEC inspections to detect cracks in the auxiliary
chord radius of the frame at BS 727, in accordance with Part 1 of
the Accomplishment Instructions of Boeing Alert Service Bulletin
737-53A1166, Revision 2, dated May 25, 2006. Repeat the inspections
thereafter at intervals not to exceed 15,000 flight cycles until the
optional terminating action described in paragraph (r) of this AD is
accomplished. If any crack is found, before further flight, repair
in accordance with the requirements in paragraph (p) of this AD.
(m) For airplanes identified in table 2 of paragraph 1.E.,
``Compliance'' of Boeing Alert Service Bulletin 737-53A1166,
Revision 2, dated May 25, 2006: Do the applicable inspections
required by paragraph (m)(1) or (m)(2) of this AD at the time
specified, in accordance with Part 1 of the Accomplishment
Instructions of Boeing Alert Service Bulletin 737-53A1166, Revision
2, dated May 25, 2006. Except as required by paragraph (p) of this
AD, if any crack is found during any inspection required by
paragraph (m)(1) or (m)(2) of this AD, before further flight, repair
in accordance with Part 3 or Part 4 of the Accomplishment
Instructions of Boeing Alert Service Bulletin 737-53A1166, Revision
2, dated May 25, 2006, as applicable. Repeat the inspections until
the optional terminating action described in paragraph (r) of this
AD is accomplished.
(1) For airplanes on which the inspections specified in Boeing
Alert Service Bulletin 737-53A1166, dated June 30, 1994; or Boeing
Service Bulletin 737-53A1166, Revision 1, dated May 25, 1995; have
not been performed as of the effective date of this AD: Do the
inspections required by paragraphs (m)(1)(i) and (m)(1)(ii) of this
AD at the time specified.
(i) Before the accumulation of 27,000 total flight cycles, or
within 5,000 flight cycles after the effective date of this AD,
whichever occurs later: Do ultrasonic and surface HFEC inspections
to detect cracks in the forward flange of the outboard chord of the
frame at BS 727. Repeat the inspections thereafter at intervals not
to exceed 5,000 flight cycles.
(ii) Before the accumulation of 27,000 total flight cycles, or
within 10,000 flight cycles after the effective date of this AD,
whichever occurs later: Do an open hole eddy current inspection to
detect cracks in the forward flange of the outboard chord of the
frame at BS 727. Repeat the inspection thereafter at intervals not
to exceed 15,000 flight cycles.
(2) For airplanes on which the inspections specified in Boeing
Alert Service Bulletin 737-53A1166, dated June 30, 1994; or Boeing
Service Bulletin 737-53A1166, Revision 1, dated May 25, 1995; have
been performed as of the effective date of this AD: Repeat the
applicable inspection specified in paragraphs (m)(1)(i) and
(m)(1)(ii) of this AD thereafter at intervals not to exceed 5,000
flight cycles for the ultrasonic and surface HFEC inspections, and
at intervals not to exceed 15,000 flight cycles for the open hole
eddy current inspection.
(n) For airplanes identified in table 3 of paragraph 1.E.,
``Compliance'' of Boeing Alert Service Bulletin 737-53A1166,
Revision 2, dated May 25, 2006: Do the applicable inspections
required by paragraph (n)(1) or (n)(2) of this AD at the time
specified, in accordance with Part 1 of the Accomplishment
Instructions of Boeing Alert Service Bulletin 737-53A1166, Revision
2, dated May 25, 2006. Except as required by paragraph (p) of this
AD, if any crack is found during any inspection required by
paragraphs (n)(1) or (n)(2) of this AD, before further flight,
repair in accordance with Part 3 or Part 4 of the Accomplishment
Instructions of Boeing Alert Service Bulletin 737-53A1166, Revision
2, dated May 25, 2006, as applicable. Repeat the inspections until
the optional terminating action described in paragraph (r) of this
AD is accomplished.
(1) For airplanes on which the inspections specified in Boeing
Alert Service Bulletin 737-53A1166, dated June 30, 1994; or Boeing
Service Bulletin 737-53A1166, Revision 1, dated May 25, 1995; have
not been done as of the effective date of this AD: Do the
inspections required by paragraphs (n)(1)(i) and (n)(1)(ii) of this
AD at the time specified.
(i) Before the accumulation of 27,000 total flight cycles, or
within 5,000 flight cycles after the effective date of this AD,
whichever occurs later: Do ultrasonic, low frequency eddy current,
and edge HFEC inspections to detect cracks in the forward flange of
the outboard chord of the frame at BS 727. Repeat the inspections
thereafter at intervals not to exceed 5,000 flight cycles.
(ii) Before the accumulation of 27,000 total flight cycles, or
within 10,000 flight cycles after the effective date of this AD,
whichever occurs later: Do an open hole eddy current inspection to
detect cracks in the forward flange of the outboard chord of the
frame at BS 727. Repeat the inspections thereafter at intervals not
to exceed 15,000 flight cycles.
(2) For airplanes on which the inspections specified in Boeing
Alert Service Bulletin 737-53A1166, dated June 30, 1994; or Boeing
Service Bulletin 737-53A1166, Revision 1, dated May 25, 1995; have
been done as of the effective date of this AD: Repeat the applicable
inspection specified in paragraphs (n)(1)(i) and (n)(1)(ii) of this
AD thereafter at intervals not to exceed 5,000 flight cycles for the
ultrasonic, low frequency eddy current, and edge HFEC inspections,
and at intervals not to exceed 15,000 flight cycles for the open
hole eddy current inspection.
Note 2: The detailed and eddy current inspections of the
outboard chord of S-18A specified in Boeing Alert Service Bulletin
737-53A1166, Revision 2, dated May 25, 2006, are not required by
this AD.
(o) For airplanes identified in table 4 of paragraph 1.E.,
``Compliance'' of Boeing Alert Service Bulletin 737-53A1166,
Revision 2, dated May 25, 2006: Before the accumulation of 50,000 or
more total flight cycles, but fewer than or equal to 60,000 total
flight cycles, after accomplishing the modification of the outboard
chord of the frame at BS 727 at S-18A: Do a one-time follow-on open
hole eddy current inspection to detect cracks in the modified chord
in accordance with Part 8 of the Accomplishment Instructions of
Boeing Alert Service Bulletin 737-53A1166, Revision 2, dated May 25,
2006.
(p) If any crack is found during any inspection required by
paragraphs (l) through (o) of this AD, and the repairs specified in
Part 3 and Part 4 of the Accomplishment Instructions of Boeing Alert
Service Bulletin 737-53A1166, Revision 2, dated May 25, 2006, can
not be installed using the procedures identified in this service
bulletin: Before further flight, repair using a method approved in
accordance with the procedures specified in paragraph (s) of this
AD.
(q) For any airplane on which a time-limited repair is installed
on the outboard chord of the frame at body station BS 727 in
accordance with Boeing Alert Service Bulletin 737-53A1166, dated
June 30, 1994; or Boeing Service Bulletin 737-53A1166, Revision 1,
dated May 25, 1995: Within 4,500 flight cycles after installation of
the repair, or within 6 months after the effective date of this AD,
whichever occurs later, replace the repair in accordance with Part 9
of the Accomplishment Instructions of Boeing Alert Service Bulletin
737-53A1166, Revision 2, dated May 25, 2006.
Optional Terminating Action
(r) Accomplishment of the applicable action specified in
paragraph (r)(1) or (r)(2) of this AD, in accordance with Part 2 of
the Accomplishment Instructions of Boeing Alert
[[Page 47527]]
Service Bulletin 737-53A1166, dated June 30, 1994; Boeing Service
Bulletin 737-53A1166, Revision 1, dated May 25, 1995; or Part 6 of
the Accomplishment Instructions of Boeing Alert Service Bulletin
737-53A1166, Revision 2, dated May 25, 2006; constitutes terminating
action for the inspections required by this AD.
(1) Installation of the preventative modification.
(2) Replacement of the cracked chord and installation of the
preventative modification.
Alternative Methods of Compliance (AMOCs)
(s)(1) The Manager, Seattle Aircraft Certification Office (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 e-mailed 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 for AD 95-12-17 are approved as AMOCs for the
corresponding provisions of this AD.
(5) For airplanes identified in tables 2, 3, and 5 of paragraph
1.E., ``Compliance'' of Boeing Alert Service Bulletin 737-53A1166,
Revision 2, dated May 25, 2006: The Manager, Seattle ACO, approves
the inspection methods, thresholds, and repetitive intervals therein
as an AMOC for the inspections of Structurally Significant Items
(SSIs) F-29A and F-29B required by paragraphs (g) and (h) of AD
2008-08-23, Amendment 39-15477 (Boeing 737-100/200/200C Supplemental
Structural Inspection Document (SSID) D6-37089, Revision E, dated
May 1, 2007), and paragraphs (g) and (h) of AD 2008-09-13, Amendment
39-15494 (Boeing 737-400/500/600 SSID D6-82669, dated May 1, 2007).
This approval applies only to SSIs F-29A and F-29B of the applicable
SSID and only for the portions of the BS 727 outer chord that have
been inspected or that have been repaired or modified in accordance
with Boeing Alert Service Bulletin 737-53A1166, Revision 2, dated
May 25, 2006. All provisions of ADs 2008-08-23 and 2008-09-13 that
are not specifically referenced in this paragraph remain fully
applicable and must be done. If operators request this AMOC, they
must revise their FAA-approved maintenance or inspection program to
incorporate the alternative inspections in this paragraph.
Related Information
(t) For more information about this AD, contact Alan Pohl,
Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle ACO,
1601 Lind Avenue, SW., Renton, Washington 98057-3356; phone: (425)
917-6450; fax: (425) 917-6590; e-mail: [email protected].
(u) For service information identified in this 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; e-mail
[email protected]; 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 July 26, 2011.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 2011-19904 Filed 8-4-11; 8:45 am]
BILLING CODE 4910-13-P