Document ID: FAA-2011-1255-0008
Agency: faa
Document Type: Rule
Title: Airworthiness Directives: The Boeing Co. Airplanes
Posted Date: 2012-06-18T04:00Z

[Federal Register Volume 77, Number 117 (Monday, June 18, 2012)]
[Rules and Regulations]
[Pages 36139-36143]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2012-14373]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2011-1255; Directorate Identifier 2010-NM-182-AD; 
Amendment 39-17084; AD 2012-12-05]
RIN 2120-AA64

Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: We are superseding two existing airworthiness directives (ADs) 
for certain Model 737-100, -200, -200C, -300, -400, and -500 series 
airplanes. The first existing AD currently requires, for certain 
airplanes, repetitive inspections of the Station (STA) 348.2 frame to 
detect cracking under the stop fittings and intercostal flanges at 
stringers S-14L, S-15L, and S-16L, and corrective action if necessary. 
The second existing AD currently requires repetitive inspections to 
detect cracking of the intercostal webs, attachment clips, and stringer 
splice channels, and corrective action if necessary. This new AD 
requires that the inspection for cracking under the stop fittings be 
done on additional airplanes; extends the repetitive interval for 
certain airplanes; adds a one-time inspection to detect missing 
fasteners; and updates or adds certain inspection and repair 
instructions. This new AD also requires, for certain airplanes, 
repetitive inspections of the cargo barrier net fitting for cracking, 
and repair if necessary. This new AD also adds, for certain airplanes, 
repetitive inspections for cracking of the stringer S-15L aft 
intercostal, and repair if necessary. This AD was prompted by reports 
of cracking of the STA 348.2 frame above the two outboard fasteners 
attaching the frame inner chord and door stop fittings, and in the 
outboard chord at stringer S-16L. We have also received reports of 
missing fasteners in the STA 348.2 frame inner chord. We are issuing 
this AD to detect and correct fatigue cracking of the intercostals on 
the forward and aft sides of the forward entry door cutout, which could 
result in loss of the forward entry door and rapid decompression of the 
airplane.

DATES: This AD is effective July 23, 2012.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in the AD as of July 23, 2012.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in the AD as of September 9, 
2009 (74 FR 38901, August 5, 2009).
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in the AD as of November 1, 
2005 (70 FR 56361, September 27, 2005).
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in the AD as of June 4, 2004 
(69 FR 23646, April 30, 2004).

ADDRESSES: 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; 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 AD, the regulatory evaluation, 
any comments received, and other information. The address for the 
Docket Office (phone: 800-647-5527) is Document Management Facility, 
U.S. Department of Transportation, Docket Operations, M-30, West 
Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE., 
Washington, DC 20590.

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: Alan.Pohl@faa.gov.

SUPPLEMENTARY INFORMATION: 

Discussion

    We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR 
part 39 to supersede airworthiness directives AD 2004-09-09, Amendment 
39-13598 (69 FR 23646, April 30, 2004); and AD 2009-16-14, Amendment 
39-15987 (74 FR 38901, August 5, 2009). Those ADs apply to the 
specified products. The NPRM published in the Federal Register on 
November 28, 2011 (76 FR 72858). The NPRM proposed to retain certain 
requirements of AD 2004-09-09 and AD 2009-16-14. The NPRM proposed to 
also add airplanes to the applicability for the high frequency eddy 
current (HFEC) inspection for cracking of the stop fittings at the 
shear web at the STA 348.2 frame; extend the repetitive interval for 
the HFEC inspection of the STA 348.2 frame for Model 737-200C 
airplanes; add an inspection to detect missing fasteners of the STA 
348.2 frame inner chord; and update or add certain inspection and 
repair instructions.

Comments

    We gave the public the opportunity to participate in developing 
this AD. The following presents the comments received on the proposal 
(76 FR 72858, November 28, 2011) and the FAA's response to each 
comment.

Support for NPRM (76 FR 72858, November 28, 2011)

    Boeing concurs with the contents of the NPRM (76 FR 72858, November 
28, 2011).

Requests To Remove or Revise Exception to Certain Service Information

    Southwest Airlines (SWA) asked that paragraph (r) of the NPRM (76 
FR 72858, November 28, 2011) be removed, or revised to provide 
clarification. SWA stated that the exception specified in paragraph (r) 
of the NPRM does not allow the sequence of steps in the Work 
Instructions of Boeing Alert Service Bulletin 737-53A1240, Revision 1, 
dated June 29, 2010, to be changed. SWA added that it has serious 
concerns

[[Page 36140]]

that this paragraph effectively eliminates all flexibility when 
accomplishing open access, the order of which locations get inspected, 
and close access. SWA noted that this becomes very difficult in a 
maintenance environment where other activities may be worked 
concurrently. SWA asked if the intent of the exception in paragraph (r) 
of the NPRM is to make removing the windscreen before the lavatory and 
removing the fasteners identified in Circle Note 1 prior to removing 
the fasteners identified in Circle Note 2 conditions of compliance. SWA 
understands that certain steps contained in Boeing Alert Service 
Bulletin 737-53A1240, Revision 1, dated June 29, 2010, might have to be 
accomplished in a specific order. However, SWA noted that the umbrella 
restriction imposed by paragraph (r) of the NPRM goes beyond that 
intent and results in restrictions when performing maintenance.
    Scandanavian Airlines Systems (SAS) asked that we include an option 
of removing the shear web before accomplishing the inspection specified 
in Boeing Alert Service Bulletin 737-53A1204, Revision 2, dated June 
24, 2010, as part of the access procedures specified in the NPRM (76 FR 
72858, November 28, 2011). SAS stated that it has previously 
accomplished the inspections as an alternative method of compliance 
(AMOC) to AD 2009-16-14, Amendment 39-15987 (74 FR 38901, August 5, 
2009). SAS noted that it also received clarification from the 
manufacturer regarding the shear web removal step in Parts 1 and 2 of 
the Accomplishment Instructions of Boeing Alert Service Bulletin 737-
53A1204, Revision 2, dated June 24, 2010. SAS stated that the shear web 
removal is not part of the inspection procedures specified in Boeing 
Alert Service Bulletin 737-53A1204, Revision 1, dated March 26, 2007.
    We agree with the commenters for the reasons provided. We have 
revised paragraph (r) of this AD accordingly.

Request To Include Reference to Previously Approved AMOCs

    SWA asked that we include a reference to AMOCs approved for AD 
2005-20-03, Amendment 39-14296 (70 FR 56361, September 27, 2005) in the 
NPRM (76 FR 72858, November 28, 2011). SWA pointed out that paragraph 
(m)(4) of AD 2009-16-14, Amendment 39-15987 (74 FR 38901, August 5, 
2009), stated that ``AMOCs approved previously in accordance with AD 
2005-20-03 are approved as AMOCs for the corresponding provisions of 
this AD, provided the repetitive inspection intervals (if any) do not 
exceed 6,000 flight cycles.'' SWA specified that paragraph (t)(5) of 
the NPRM can be interpreted to mean that an AMOC issued for AD 2005-20-
03, which was approved as an AMOC to AD 2009-16-14, will be considered 
as an AMOC to the NPRM.
    We agree with the commenter that AMOCs approved for AD 2005-20-03, 
Amendment 39-14296 (70 FR 56361, September 27, 2005), as specified in 
paragraph (m)(4) of AD 2009-16-14, Amendment 39-15987 (74 FR 38901, 
August 5, 2009), are still approved for the corresponding requirements 
of this AD. For clarity, we have added a new paragraph (t)(5) to this 
AD to include that information, and we reidentified the existing 
paragraph (t)(5) of the NPRM (76 FR 72858, November 28, 2011) as 
paragraph (t)(6) in this final rule.

Explanation of Additional Changes Made to This AD

    We have clarified the compliance time in paragraph (q) of this AD 
by adding the phrase ``whichever occurs later.''
    We have updated certain headings throughout this AD.

Conclusion

    We reviewed the relevant data, considered the comments received, 
and determined that air safety and the public interest require adopting 
the AD with the changes described previously--and minor editorial 
changes. We have determined that these minor changes:
     Are consistent with the intent that was proposed in the 
NPRM (76 FR 72858, November 28, 2011) for correcting the unsafe 
condition; and
     Do not add any additional burden upon the public than was 
already proposed in the NPRM (76 FR 72858, November 28, 2011).

Costs of Compliance

    We estimate that this AD affects 581 airplanes of U.S. registry.
    We estimate the following costs to comply with this AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                  Cost per
            Action                Labor cost      Parts cost      product            Cost on U.S. operators
----------------------------------------------------------------------------------------------------------------
Inspections for cracking       18 work-hours x            $0  $1,530 per       $888,930 per inspection cycle.
 under the stop fittings and    $85 per hour =                 inspection
 intercostal flanges            $1,530 per                     cycle.
 [retained from AD 2004-09-     inspection
 09, Amendment 39-13598 (69     cycle.
 FR 23646, April 30, 2004)].
Inspection of areas forward    2 work-hours x              0  $170 per         $98,770 per inspection cycle.
 of the aft entry door          $85 per hour =                 inspection
 [retained from AD 2009-16-     $170 per                       cycle.
 14, Amendment 39-15987 (74     inspection
 FR 38901, August 5, 2009)].    cycle.
Inspection of areas aft of     1 work-hour x               0  $85 per          $49,385 per inspection cycle.
 the forward entry door         $85 per hour =                 inspection
 [retained from AD 2009-16-     $85 per                        cycle.
 14, Amendment 39-15987 (74     inspection
 FR 38901, August 5, 2009)].    cycle.
Inspection for missing         1 work-hour x             476  $561...........  $325,941.
 fasteners [new action].        $85 per hour =
                                $85.
----------------------------------------------------------------------------------------------------------------

    We estimate the following costs to do any necessary repairs that 
would be required based on the results of the inspections. We have no 
way of determining the number of aircraft that might need these 
repairs:

[[Page 36141]]

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                Action                        Labor cost                Parts cost            Cost per product
----------------------------------------------------------------------------------------------------------------
Repair of cracking if done in          Unknown.................  Unknown.................  Unknown.
 accordance with a method approved by
 the FAA.
Repair of cracking if done in          24 work-hours...........  $11,856.................  $13,896.
 accordance with Boeing Alert Service
 Bulletin 737-53A1240, Revision 1,
 dated June 29, 2010.
----------------------------------------------------------------------------------------------------------------

    According to the manufacturer, some of the costs of this AD may be 
covered under warranty, thereby reducing the cost impact on affected 
individuals. We do not control warranty coverage for affected 
individuals. As a result, we have included all costs in our cost 
estimate.

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 AD will not have federalism 
implications under Executive Order 13132. This AD will 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 this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Is not a ``significant rule'' under 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.

Adoption of the Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
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]

0
2. The FAA amends Sec.  39.13 by removing airworthiness directive (AD) 
2004-09-09, Amendment 39-13598 (69 FR 23646, April 30, 2004); and AD 
2009-16-14, Amendment 39-15987 (74 FR 38901, August 5, 2009); and 
adding the following new AD:

2012-12-05 The Boeing Company: Amendment 39-17084; Docket No. FAA-
2011-1255; Directorate Identifier 2010-NM-182-AD.

(a) Effective Date

    This airworthiness directive (AD) is effective July 23, 2012.

(b) Affected ADs

    This AD supersedes AD 2004-09-09, Amendment 39-13598 (69 FR 
23646, April 30, 2004); and AD 2009-16-14, Amendment 39-15987 (74 FR 
38901, August 5, 2009).

(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 reports of cracking of the station (STA) 
348.2 frame above the two outboard fasteners attaching the frame 
inner chord and door stop fittings, and in the outboard chord at 
stringer S-16L. We have also received reports of missing fasteners 
in the STA 348.2 frame inner chord. We are issuing this AD to detect 
and correct fatigue cracking of the intercostals on the forward and 
aft sides of the forward entry door cutout, which could result in 
loss of the forward entry door and rapid decompression of the 
airplane.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Retained Initial and Repetitive Inspections at STA 348.2 for Model 
737-200C Series Airplanes

    This paragraph restates the requirements of paragraph (a) of AD 
2004-09-09, Amendment 39-13598 (69 FR 23646, April 30, 2004), with 
revised service information. For Model 737-200C series airplanes: 
Except as provided by paragraph (h) of this AD, prior to the 
accumulation of 46,000 total flight cycles, or within 2,250 flight 
cycles after June 4, 2004 (the effective date of AD 2004-09-09), 
whichever occurs later, do detailed and eddy current inspections of 
the STA 348.2 frame for cracking under the stop fittings and 
intercostal flanges at stringers 14L, 15L, and 16L by accomplishing 
paragraphs 3.A and 3.B.1 through 3.B.7 of the Accomplishment 
Instructions of Boeing Alert Service Bulletin 737-53A1240, dated 
April 10, 2003; or by accomplishing Part 1 of the Accomplishment 
Instructions of Boeing Alert Service Bulletin 737-53A1240, Revision 
1, dated June 29, 2010. Do the actions in accordance with Boeing 
Alert Service Bulletin 737-53A1240, dated April 10, 2003; or Boeing 
Alert Service Bulletin 737-53A1240, Revision 1, dated June 29, 2010. 
Any applicable repair must be accomplished prior to further flight. 
Repeat the inspections thereafter at intervals not to exceed 6,000 
flight cycles. As of the effective date of this AD, only Boeing 
Alert Service Bulletin 737-53A1240, Revision 1, dated June 29, 2010, 
may be used to accomplish the actions required by this paragraph.

(h) Retained Corrective Action for Paragraph (g) of This AD

    This paragraph restates the requirements of paragraph (b) of AD 
2004-09-09, Amendment 39-13598 (69 FR 23646, April 30, 2004), with 
revised service information. If any crack is found during any 
inspection required by paragraph (g) of this AD, and Boeing Alert 
Service Bulletin 737-53A1240, dated April 10, 2003; or Boeing Alert 
Service Bulletin 737-53A1240, Revision 1, dated June 29, 2010; 
specifies to contact Boeing for appropriate action: Before further 
flight, repair in accordance with a method approved by the Manager, 
Seattle Aircraft Certification Office (ACO), FAA; or using a method 
approved in accordance with the procedures specified in paragraph 
(t) of this AD.

[[Page 36142]]

(i) Retained Initial Compliance Time for Model 737-100, -200, -200C, -
300, -400, and -500 Series Airplanes

    This paragraph restates the requirements of paragraph (f) of AD 
2009-16-14, Amendment 39-15987 (74 FR 38901, August 5, 2009). For 
all Model 737-100, -200, -200C, -300, -400, and -500 series 
airplanes, as identified in Boeing Alert Service Bulletin 737-
53A1204, Revision 1, dated March 26, 2007: Before the accumulation 
of 15,000 total flight cycles, or within 4,500 flight cycles after 
November 1, 2005 (the effective date of AD 2005-20-03, Amendment 39-
14296 (70 FR 56361, September 27, 2005)), whichever occurs later: Do 
the inspections required by paragraphs (k) and (l) of this AD.

(j) Retained Initial Compliance Time for Model 737-200C Series 
Airplanes

    This paragraph restates the requirements of paragraph (g) of AD 
2009-16-14, Amendment 39-15987 (74 FR 38901, August 5, 2009). For 
all Model 737-200C series airplanes, as identified in Boeing Alert 
Service Bulletin 737-53A1204, Revision 1, dated March 26, 2007: 
Before the accumulation of 15,000 total flight cycles, or within 
4,500 flight cycles after September 9, 2009 (the effective date of 
AD 2009-16-14), whichever occurs later, do the inspection required 
by paragraph (m) of this AD.

(k) Retained Initial Inspection for Group 1 Configuration Airplanes

    This paragraph restates the requirements of paragraph (h) of AD 
2009-16-14, Amendment 39-15987 (74 FR 38901, August 5, 2009), with 
revised service information. For Group 1 airplanes identified in 
Boeing Alert Service Bulletin 737-53A1204, Revision 1, dated March 
26, 2007: Perform a detailed inspection for cracking of the 
intercostal web, attachment clips, and stringer splice channels; and 
a high frequency eddy current (HFEC) inspection for cracking of the 
stringer splice channels located forward and aft of the forward 
entry door; and do all applicable corrective actions before further 
flight; in accordance with Parts 1 and 2 of the Work Instructions of 
Boeing Special Attention Service Bulletin 737-53-1204, dated June 
19, 2003, or Boeing Alert Service Bulletin 737-53A1204, Revision 1, 
dated March 26, 2007; or in accordance with Parts 1, 2, 4, and 5 of 
the Work Instructions of Boeing Alert Service Bulletin 737-53A1204, 
Revision 2, dated June 24, 2010. After September 9, 2009 (the 
effective date of AD 2009-16-14, Amendment 39-15987 (74 FR 38901, 
August 5, 2009), and until the effective date of this AD, Boeing 
Alert Service Bulletin 737-53A1204, Revision 1, dated March 26, 
2007; or Boeing Alert Service Bulletin 737-53A1204, Revision 2, 
dated June 24, 2010; may be used to accomplish the actions required 
by this paragraph. As of the effective date of this AD, only Boeing 
Alert Service Bulletin 737-53A1204, Revision 2, dated June 24, 2010, 
may be used to accomplish the actions required by this paragraph.

(l) Retained Initial Inspection for Cargo Configuration Airplanes 
(Forward of the Forward Entry Door)

    This paragraph restates the requirements of paragraph (i) of AD 
2009-16-14, Amendment 39-15987 (74 FR 38901, August 5, 2009), with 
revised service information. For Group 2 cargo airplanes identified 
in Boeing Alert Service Bulletin 737-53A1204, Revision 1, dated 
March 26, 2007: Perform a detailed inspection for cracking of the 
intercostal webs and attachment clips located forward of the forward 
entry door, and do all applicable corrective actions before further 
flight, in accordance with Part 3 of the Work Instructions of Boeing 
Special Attention Service Bulletin 737-53-1204, dated June 19, 2003, 
or Boeing Alert Service Bulletin 737-53A1204, Revision 1, dated 
March 26, 2007; or in accordance with Part 3 of Boeing Alert Service 
Bulletin 737-53A1204, Revision 2, dated June 24, 2010. After 
September 9, 2009 (the effective date of AD 2009-16-14, Amendment 
39-15987 (74 FR 38901, August 5, 2009), and until the effective date 
of this AD, Boeing Alert Service Bulletin 737-53A1204, Revision 1, 
dated March 26, 2007; or Boeing Alert Service Bulletin 737-53A1204, 
Revision 2, dated June 24, 2010; may be used to accomplish the 
actions required by this paragraph. As of the effective date of this 
AD, only Boeing Alert Service Bulletin 737-53A1204, Revision 2, 
dated June 24, 2010, may be used to accomplish the actions required 
by this paragraph.

(m) Retained Initial Inspection for Cargo Configuration Airplanes (Aft 
of the Forward Entry Door)

    This paragraph restates the requirements of paragraph (j) of AD 
2009-16-14, Amendment 39-15987 (74 FR 38901, August 5, 2009), with 
revised service information. For Group 2 cargo airplanes identified 
in Boeing Alert Service Bulletin 737-53A1204, Revision 1, dated 
March 26, 2007: Perform a detailed inspection for cracking of the 
intercostal webs and attachment clips located aft of the forward 
entry door, and do all applicable corrective actions before further 
flight, in accordance with Part 4 of the Work Instructions of Boeing 
Alert Service Bulletin 737-53A1204, Revision 1, dated March 26, 
2007; or in accordance with Part 3 of Boeing Alert Service Bulletin 
737-53A1204, Revision 2, dated June 24, 2010. As of the effective 
date of this AD, only Boeing Alert Service Bulletin 737-53A1204, 
Revision 2, dated June 24, 2010, may be used to accomplish the 
actions required by this paragraph.

(n) Retained Repeat Inspections

    This paragraph restates the requirements of paragraph (k) of AD 
2009-16-14, Amendment 39-15987 (74 FR 38901, August 5, 2009). Repeat 
the inspections required by paragraphs (k), (l), and (m) of this AD 
thereafter at intervals not to exceed 6,000 flight cycles after the 
previous inspection, or within 3,000 flight cycles after September 
9, 2009 (the effective date of AD 2009-1614), whichever occurs 
later.

(o) Retained Exceptions to Boeing Special Attention Service Bulletin 
737-53-1204

    This paragraph restates the requirements of paragraph (l) of AD 
2009-16-14, Amendment 39-15987 (74 FR 38901, August 5, 2009), with 
revised service information. Do the actions required by paragraphs 
(i), (j), (k), (l), (m), and (n) of this AD by accomplishing all the 
applicable actions specified in the Accomplishment Instructions of 
Boeing Special Attention Service Bulletin 737-53-1204, dated June 
19, 2003; Boeing Alert Service Bulletin 737-53A1204, Revision 1, 
dated March 26, 2007; or Boeing Alert Service Bulletin 737-53A1204, 
Revision 2, dated June 24, 2010; except as provided by paragraphs 
(o)(1) and (o)(2) of this AD. After September 9, 2009 (the effective 
date of AD 2009-16-14), and until the effective date of this AD, 
Boeing Alert Service Bulletin 737-53A1204, Revision 1, dated March 
26, 2007; or Boeing Alert Service Bulletin 737-53A1204, Revision 2, 
dated June 24, 2010; may be used to accomplish the actions required 
by this paragraph. As of the effective date of this AD, only Boeing 
Alert Service Bulletin 737-53A1204, Revision 2, dated June 24, 2010, 
may be used to accomplish the actions required by this paragraph.
    (1) Where Boeing Special Attention Service Bulletin 737-53-1204, 
dated June 19, 2003; Boeing Alert Service Bulletin 737-53A1204, 
Revision 1, dated March 26, 2007; or Boeing Alert Service Bulletin 
737-53A1204, Revision 2, dated June 24, 2010; specifies to contact 
Boeing for repair instructions: Before further flight, repair using 
a method approved in accordance with the procedures specified in 
paragraph (t) of this AD.
    (2) Where Boeing Special Attention Service Bulletin 737-53-1204, 
dated June 19, 2003; or Boeing Alert Service Bulletin 737-53A1204, 
Revision 1, dated March 26, 2007; specifies a compliance time 
relative to the date of a service bulletin, this AD requires 
compliance relative to September 9, 2009 (the effective date of AD 
2009-16-14, Amendment 39-15987 (74 FR 38901, August 5, 2009). Where 
Boeing Special Attention Service Bulletin 737-53-1204, dated June 
19, 2003; or Boeing Alert Service Bulletin 737-53A1204, Revision 1, 
dated March 26, 2007; specifies a compliance time relative to the 
date of the initial release of a service bulletin, this AD requires 
compliance relative to November 1, 2005 (the effective date of AD 
2005-20-03, Amendment 39-14296 (70 FR 56361, September 27, 2005)).

(p) New One-Time Inspection for Missing Fasteners at STA 348.2

    For Groups 2 and 3 airplanes identified in Boeing Alert Service 
Bulletin 737-53A1240, Revision 1, dated June 29, 2010: Within 4,500 
flight cycles after the effective date of this AD, do a detailed 
inspection to detect missing fasteners of the STA 348.2 frame, in 
accordance with the Accomplishment Instructions of Boeing Alert 
Service Bulletin 737-53A1240, Revision 1, dated June 29, 2010, 
except as required by paragraph (r) of this AD. If any fastener is 
missing, before further flight, repair using a method approved in 
accordance with the procedures specified in paragraph (t) of this 
AD.

[[Page 36143]]

(q) New Initial and Repetitive Inspections at STA 348.2 for Model 737-
100, -200, -300, -400, and -500 Series Airplanes

    For Groups 2 and 3 airplanes identified in Boeing Alert Service 
Bulletin 737-53A1240, Revision 1, dated June 29, 2010: Before the 
accumulation of 15,000 total flight cycles, or within 4,500 flight 
cycles after the effective date of this AD, whichever occurs later, 
do HFEC and surface eddy current inspections for cracking of the 
frame, HFEC inspections for cracking of the reinforcement angle and 
shear web, and a detailed inspection for cracking of the STA 348.2 
frame outer chord, inner chord, and reinforcement angle, in 
accordance with the Accomplishment Instructions of Boeing Alert 
Service Bulletin 737-53A1240, Revision 1, dated June 29, 2010, 
except as required by paragraph (r) of this AD. If any crack is 
found during any inspection required by this paragraph, before 
further flight, do all applicable corrective actions in accordance 
with the Accomplishment Instructions of Boeing Alert Service 
Bulletin 737-53A1240, Revision 1, dated June 29, 2010, except as 
required by paragraph (r) of this AD, and except where that service 
bulletin specifies to contact Boeing, before further flight, repair 
using a method approved in accordance with the procedures specified 
in paragraph (t) of this AD. Repeat the inspections thereafter at 
intervals not to exceed 6,000 flight cycles.

(r) New Exceptions to Boeing Alert Service Bulletins 737-53A1204 and 
737-53A1240

    (1) Note 1 of paragraph 3.A of the Accomplishment Instructions 
of Boeing Alert Service Bulletin 737-53A1240, Revision 1, dated June 
29, 2010, is to be disregarded when accomplishing the actions 
required by this AD.
    (2) The access and restoration instructions identified in the 
Work Instructions of Boeing Alert Service Bulletin 737-53A1204, 
Revision 2, dated June 24, 2010; and Boeing Alert Service Bulletin 
737-53A1240, Revision 1, dated June 29, 2010; are not required by 
this AD. Operators may perform those actions in accordance with 
approved maintenance procedures.
    (3) The use of Boeing Drawing 65-88700 is not allowed when 
accomplishing the actions required by this AD in accordance with the 
Work Instructions of Boeing Alert Service Bulletin 737-53A1204, 
Revision 2, dated June 24, 2010; and Boeing Alert Service Bulletin 
737-53A1240, Revision 1, dated June 29, 2010.

(s) New Initial and Repetitive Inspections of the S-15L Aft Intercostal 
and Cargo Barrier Net Fitting for Model 737-200C Series Airplanes

    For Group 2 airplanes identified in Boeing Alert Service 
Bulletin 737-53A1204, Revision 2, dated June 24, 2010: Before the 
accumulation of 15,000 total flight cycles, or within 4,500 flight 
cycles after the effective date of this AD, whichever occurs later, 
do initial detailed and HFEC inspections for cracking of the S-15L 
aft intercostal between BS 348.2 and BS 360, and do a detailed 
inspection of the cargo barrier net fitting at the intercostal, in 
accordance with Figure 3 of the Accomplishment Instructions of 
Boeing Alert Service Bulletin 737-53A1204, Revision 2, dated June 
24, 2010. If any cracking is found, before further flight repair 
using a method approved in accordance with the procedures specified 
in paragraph (t) of this AD. Repeat the inspections thereafter at 
intervals not to exceed 6,000 flight cycles.

(t) 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, it may be emailed to: 9-ANM-Seattle-ACO-AMOC-Requests@faa.gov.
    (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 2004-09-09, 
Amendment 39-13598 (69 FR 23646, April 30, 2004), are approved as 
AMOCs for the corresponding requirements of this AD.
    (5) AMOCs approved previously in accordance with AD 2005-20-03, 
Amendment 39-14296 (70 FR 56361, September 27, 2005), are approved 
as AMOCs for the corresponding requirements of this AD, provided the 
repetitive inspection intervals (if any) do not exceed 6,000 flight 
cycles.
    (6) AMOCs approved previously in accordance with AD 2009-16-14, 
Amendment 39-15987 (74 FR 38901, August 5, 2009), are approved as 
AMOCs for the corresponding requirements of this AD.

(u) Related Information

    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; email: Alan.Pohl@faa.gov.

(v) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) under 5 U.S.C. 552(a) and 1 CFR 
part 51.
    (2) You must use the following service information to do the 
actions required by this AD, unless the AD specifies otherwise.
    (3) The following service information was approved for IBR on 
July 23, 2012.
    (i) Boeing Alert Service Bulletin 737-53A1240, Revision 1, dated 
June 29, 2010.
    (ii) Boeing Alert Service Bulletin 737-53A1204, Revision 2, 
dated June 24, 2010.
    (4) The following service information was approved for IBR on 
September 9, 2009 (74 FR 38901, August 5, 2009).
    (i) Boeing Alert Service Bulletin 737-53A1204, Revision 1, dated 
March 26, 2007.
    (5) The following service information was approved for IBR on 
November 1, 2005 (70 FR 56361, September 27, 2005).
    (i) Boeing Special Attention Service Bulletin 737-53-1204, dated 
June 19, 2003.
    (6) The following service information was approved for IBR on 
June 4, 2004 (69 FR 23646, April 30, 2004).
    (i) Boeing Alert Service Bulletin 737-53A1240, dated April 10, 
2003.
    (7) 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; Internet https://www.myboeingfleet.com.
    (8) 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.
    (9) You may also review copies of the service information that 
is incorporated by reference at the National Archives and Records 
Administration (NARA). For information on the availability of this 
material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr_locations.html.

    Issued in Renton, Washington, on June 4, 2012.
Michael Kaszycki,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2012-14373 Filed 6-15-12; 8:45 am]
BILLING CODE 4910-13-P