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[Federal Register: March 9, 2010 (Volume 75, Number 45)]
[Rules and Regulations]               
[Page 10658-10664]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr09mr10-4]                         

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2009-0452; Directorate Identifier 2007-NM-326-AD; 
Amendment 39-16223; AD 2010-05-13]
RIN 2120-AA64

 
Airworthiness Directives; The Boeing Company Model 737-100, -200, 
-200C, -300, -400, and -500 Series Airplanes

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Final rule.

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SUMMARY: The FAA is superseding an existing airworthiness directive 
(AD) that applies to all Model 737-100, -200, -200C, -300, -400, and -
500 series airplanes. That AD currently requires a one-time inspection 
for scribe lines and cracks in the fuselage skin at certain lap joints, 
butt joints, external repair doublers, and other areas; and related 
investigative/corrective actions if necessary. This new AD expands the 
area to be inspected and, for certain airplanes, requires earlier 
inspections for certain inspection zones. This AD results from 
additional detailed analysis of fuselage skin cracks adjacent to the 
skin lap joints on airplanes that had scribe lines. The analysis 
resulted in different inspection zones, thresholds and repetitive 
intervals, and airplane groupings. We are issuing this AD to prevent 
rapid decompression of the airplane due to fatigue cracks resulting 
from scribe lines on pressurized fuselage structure.

DATES: This AD becomes effective April 13, 2010.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in the AD as of April 13, 
2010.

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; e-mail me.boecom@boeing.com; 
Internet https://www.myboeingfleet.com.

[[Page 10659]]

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 (telephone 800-647-5527) is the 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: Wayne Lockett, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office 
(ACO), 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone 
(425) 917-6447; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

Discussion

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 to include an AD that supersedes AD 2006-07-12, Amendment 
39-14539 (71 FR 16211, March 31, 2006). The existing AD applies to all 
Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. That 
NPRM was published in the Federal Register on May 20, 2009 (74 FR 
23664). That NPRM proposed to expand the area to be inspected and, for 
certain airplanes, require earlier inspections for certain inspection 
zones.

Comments

    We provided the public the opportunity to participate in the 
development of this AD. We have considered the comments that have been 
received on the NPRM.

Support for the NPRM

    Air Transport Association (ATA), on behalf of its members Alaska 
Airlines and United Airlines (United), agrees with the assessment and 
states that those two members will comply with the requirements of the 
NPRM.

Request To Change Reference in Paragraph (g)(2) of the NPRM

    Boeing requests that we change paragraph (g)(2) of the NPRM to 
refer to paragraph (i) of the NPRM instead of paragraph (h) of the 
NPRM. Boeing notes that this section is in the Restatement of 
Requirements of AD 2006-07-12, and making this change matches the 
original AD requirements.
    We agree to change the reference from paragraph (h) to paragraph 
(i) of this AD for the reasons stated previously.

Request To Clarify Area of Inspection in Paragraph (r) of the NPRM

    Boeing requests that we remove the parenthetical phrase ``(adjacent 
to lap joints on skin panels that do not have bonded doublers)'' from 
paragraph (r) of the NPRM. Boeing states that this statement is not 
true in all cases. Boeing notes that in some cases the skins under the 
lap joints in Zones 4 and 5 are bonded, but they are closed pockets 
that are not chem-milled all the way through the thickness.
    We agree to remove the parenthetical phrase from paragraph (r) of 
this AD for the reasons stated previously.

Request To Clarify Instructions for Inspections Under the Edge of 
Hinges on the Main Cargo Door

    Boeing requests that we clarify the instructions for inspections 
under the edge of hinges on the main cargo door. Boeing notes that 
Boeing Alert Service Bulletin 737-53A1262, Revision 3, dated October 
16, 2008, does not give specific instructions for inspections of scribe 
lines found under the edge of the hinge on the main cargo door. Boeing 
requests that we add a statement to provide instructions for 
inspections in this area. Boeing states that the lap joint inspection 
method specified in Boeing Alert Service Bulletin 737-53A1262, Revision 
3, dated October 16, 2008, applies to the hinge detail.
    We agree that additional clarification is necessary. We have added 
paragraph (s)(4)(iv) to the AD to provide additional instructions for 
inspections along the lower edge of the main cargo door for the reasons 
that the commenter provided. We also determined that this change does 
not increase the economic burden on any operator or increase the scope 
of the AD.

Request To Revise Paragraph (t) of the NPRM

    Lufthansa requests that we revise paragraph (t) of the NPRM. 
Lufthansa requests that we clarify whether Zones 4 and 5 are derived 
from the former Zones 1, 2, and 3 as identified in the initial release 
of Boeing Alert Service Bulletin 737-53A1262, dated December 9, 2004. 
Lufthansa requests that we accept inspections performed in Zones 1, 2, 
and 3 in accordance with Boeing Alert Service Bulletin 737-53A1262, 
dated December 9, 2004, as acceptable for compliance with the 
requirements of paragraphs (q) and (r) of the NPRM.
    We agree. The new zones were created by moving specific areas from 
the existing Zones 1, 2, and 3, and have been inspected as required by 
AD 2006-07-12. We have revised paragraph (t) of this AD to give credit 
for inspections accomplished before the effective date of this AD as 
acceptable for compliance for the requirements of paragraphs (q) and 
(r) of this AD.

Request To Provide an Additional Grace Period

    Lufthansa requests that we provide an additional grace period. 
Lufthansa notes that areas that were shifted to a more critical zone 
must be inspected within 4,500 flight cycles after the effective date 
of the AD or before reaching the applicable zonal inspection threshold, 
whichever occurs later. For any of the new critical zones that are 
inspected in accordance with the requirements of the full Limited 
Return to Service (LRTS) program because of previous scribe line 
findings in the adjacent zone on the same lap splice between two butt 
joints, Lufthansa requests that we extend the grace period to reach the 
next heavy maintenance event to do the inspection. Lufthansa states 
that this may be valid only for airplanes and areas where the 
requirements of the full LRTS are applied.
    We disagree with the request to extend the grace period. The 4,500-
flight-cycle grace period applies only to the initial scribe line 
inspections and does not apply to airplanes with scribe lines that are 
currently being monitored in the LRTS program. Operators may request an 
alternative method of compliance (AMOC) in accordance with the 
requirements of paragraph (y) of this AD. We have not changed the AD in 
regard to this issue.

Request To Clarify Procedures for Scribe Lines Outside Structural 
Repair Manual (SRM) Limits

    Lufthansa requests that we clarify procedures for areas with scribe 
lines that have become ``no zone'' (i.e., areas on the fuselage where 
scribe line inspections are not required) and are inspected in 
accordance with the LRTS program described in Boeing Alert Service 
Bulletin 737-53A1262, Revision 3, dated October 16, 2008. Lufthansa 
notes that the scribe damage in the ``no zone'' may be out of the SRM 
limits and may need to be repaired before further flight because the 
LRTS is no longer applicable.
    We disagree that additional procedures are necessary. Note 5 in 
paragraph 3.A. in the Accomplishment Instructions of Boeing Alert 
Service Bulletin 737-53A1262, Revision 3, dated October 16, 2008, 
provides instructions on how to proceed with

[[Page 10660]]

scribe lines in any area that is not shown in Zone 1, 2, 3, 4, or 5. We 
have not changed the AD in regard to this issue.

Request To Verify Inspection Threshold

    ATA, on behalf of its member United, requests that we verify the 
inspection threshold. United notes that the inspection threshold 
specified in FAA Approval Letter 120S-06-141 is the accumulation of 
40,000 to 50,000 flight cycles. United states that neither the AMOC nor 
Boeing Alert Service Bulletin 737-53A1262, Revision 3, dated October 
16, 2008, requires this terminating inspection to be accomplished after 
the accumulation of 40,000 flight cycles. United requests that we 
verify that this inspection cannot be performed before the accumulation 
of 40,000 flight cycles.
    We agree that clarification may be necessary, and we agree to 
verify the threshold. This inspection cannot be performed for credit 
before the accumulation of 40,000 total flight cycles. After reviewing 
the scribe line damage adjacent to the lap joints, we determined that 
the terminating inspection performed in accordance with Boeing Service 
Bulletin 737-53-1179, Revision 2, dated October 25, 2006, mandated by 
AD 2003-14-06, Amendment 39-13225 (68 FR 42956, July 21, 2003), should 
be accomplished again in accordance with AD 2003-14-06 in the areas of 
known scribe lines after the accumulation of 40,000 total flight 
cycles. This inspection is designed to ensure that the underlying 
substructure is intact and would have no effect on the LRTS program. We 
have not changed the AD regarding this issue.

Request To Clarify Whether Inspection is Required

    ATA, on behalf of its member United, asks that we clarify whether 
the inspection required by paragraph (g) of the NPRM is required if 
operators have accomplished the terminating action in accordance with 
AMOC 120S-06-209 for AD 2003-14-06.
    We agree that clarification is necessary. We have approved the 
inspection methods specified in FAA Approval Letter 120S-06-209, dated 
April 13, 2006, as an AMOC to the terminating action requirements of 
paragraph (b) of AD 2003-14-06. Paragraph 12.a.(2), of Part 12 of the 
Accomplishment Instructions of Boeing Service Bulletin 737-53A1262, 
Revision 1, dated March 1, 2007; Revision 2, dated September 20, 2007; 
and Revision 3, dated October 16, 2008; specify internal inspections in 
accordance with Boeing Service Bulletin 737-53-1179, Revision 2, dated 
October 25, 2001, except for airplanes inspected internally in 
accordance with paragraph (b) of AD 2003-14-06. Inspections 
accomplished in accordance with FAA Approval Letter 120S-06-209, dated 
April 13, 2006, are approved as an acceptable alternative method of 
compliance to the internal inspections specified in Paragraph 12.a.(2) 
of Part 12 of the Accomplishment Instructions of Boeing Service 
Bulletin 737-53A1262, Revision 1, dated March 1, 2007; Revision 2, 
dated September 20, 2007; and Revision 3, dated October 16, 2008; and 
required by paragraph (b) of AD 2003-14-06. We have added a reference 
to previously approved AMOCs in paragraph (x) of this AD.

Request To Clarify Butt-to-Butt Inspection Requirements

    ATA, on behalf of its member United, requests that we clarify that 
the butt-to-butt inspection is only for areas where a scribe line is 
found within 0.063 inches of the upper skin areas in a zone.
    We agree that clarification may be necessary. Figure 128 of Boeing 
Alert Service Bulletin 737-53A1262, Revision 3, dated October 16, 2008, 
indicates that butt-to-butt inspections are required for all scribe 
lines within 0.10 inch of the lap joint upper skin. We have not changed 
the AD regarding this issue.

Request To Issue Similar Rulemaking

    The National Transportation Safety Board (NTSB) notes that while 
the NPRM addresses scribe-type damage on Model 737 airplanes, it is 
concerned that this type of damage is not limited to Model 737 
airplanes. The NTSB urges that we conduct similar analyses and issue 
similar rulemaking for other makes and models of airplanes.
    We acknowledge the NTSB's concerns. This issue is a long-term 
durability issue that is not limited to any particular airplane model. 
We are currently working to address scribe line issues on other 
airplanes. The effect on each airplane model varies with each model's 
design characteristics and the conditions under which they have been 
operated. We have been in contact with other governing regulatory 
agencies and manufacturers, and we may consider further rulemaking as a 
result of these efforts. We have not changed the AD in regard to this 
issue.

Explanation of Change Made to This AD

    Boeing Commercial Airplanes has received an Organization 
Designation Authorization (ODA), which replaces their previous 
designation as a Delegation Option Authorization (DOA) holder. We have 
revised paragraph (y)(3) of this AD to delegate the authority to 
approve an alternative method of compliance for any repair required by 
this AD to the Boeing Commercial Airplanes ODA.

Conclusion

    We have carefully reviewed the available data, including the 
comments that have been received, and determined that air safety and 
the public interest require adopting the AD with the changes described 
previously. We have determined that these changes will neither increase 
the economic burden on any operator nor increase the scope of the AD.

Explanation of Change to Costs of Compliance

    Since issuance of the NPRM, we have increased the labor rate used 
in the Costs of Compliance from $80 per work-hour to $85 per work-hour. 
The Costs of Compliance information, below, reflects this increase in 
the specified hourly labor rate.

Costs of Compliance

    There are about 2,685 airplanes of the affected design in the 
worldwide fleet. The following table provides the estimated costs, 
including the costs for the new inspection areas in Zones 4 and 5, for 
U.S. operators to comply with this AD.

                                                        Estimated Costs Required by AD 2006-07-12
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                          Number of U.S.-
                 Zone                                Action                 Work hours     Average labor     Cost per       registered      Fleet cost
                                                                                           rate per hour     airplane        airplanes
--------------------------------------------------------------------------------------------------------------------------------------------------------
1.....................................  Sealant removal.................              66             $85          $5,610             787      $4,415,070
                                        Inspection......................               4              85             340              87         267,580
2.....................................  Sealant removal.................              38              85           3,230             787       2,542,010
                                        Inspection......................              29              85           2,465             787       1,939,955

[[Page 10661]]


3.....................................  Sealant removal.................              88              85           7,480             787       5,886,760
                                        Inspection......................              38              85           3,230             787       2,542,010
--------------------------------------------------------------------------------------------------------------------------------------------------------


                                                   Estimated Costs Required by New Actions of This AD
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                          Number of U.S.-
                 Zone                                Action                 Work hours     Average labor     Cost per       registered      Fleet cost
                                                                                           rate per hour     airplane        airplanes
--------------------------------------------------------------------------------------------------------------------------------------------------------
4.....................................  Sealant removal.................              15             $85          $1,275             787     $ 1,003,425
                                        Inspection......................               1              85              85             787          66,895
5.....................................  Sealant removal.................              31              85           2,635             787       2,073,745
                                        Inspection......................               2              85             170             787         133,790
--------------------------------------------------------------------------------------------------------------------------------------------------------

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); and
    (3) 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.
    We prepared a regulatory evaluation of the estimated costs to 
comply with this AD and placed it in the AD docket. See the ADDRESSES 
section for a location to examine the regulatory evaluation.

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 Federal Aviation Administration (FAA) amends Sec.  39.13 by 
removing amendment 39-14539 (71 FR 16211, March 31, 2006) and by adding 
the following new airworthiness directive (AD):

2010-05-13 The Boeing Company: Amendment 39-16223. Docket No. FAA-
2009-0452; Directorate Identifier 2007-NM-326-AD.

Effective Date

    (a) This AD becomes effective April 13, 2010.

Affected ADs

    (b) This AD supersedes AD 2006-07-12, Amendment 39-14539.

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) Air Transport Association (ATA) of America Code 53: 
Fuselage.

Unsafe Condition

    (e) This AD results from reports of fuselage skin cracks 
adjacent to the skin lap joints on airplanes that had scribe lines. 
Scribe line damage can also occur at many other locations, including 
butt joints, external doublers, door scuff plates, the wing-to-body 
fairing, and areas of the fuselage where decals have been applied or 
removed. We are issuing this AD to prevent rapid decompression of 
the airplane due to fatigue cracks resulting from scribe lines on 
pressurized fuselage structure.

Compliance

    (f) You are responsible for having the actions required by this 
AD performed within the compliance times specified, unless the 
actions have already been done.

Restatement of Requirements of AD 2006-07-12

Inspection

    (g) Do a detailed inspection for scribe lines and cracks in the 
fuselage skin at certain lap joints, butt joints, external repair 
doublers, and other areas, in accordance with the Accomplishment 
Instructions of Boeing Alert Service Bulletin 737-53A1262, dated 
December 9, 2004, except as provided by paragraphs (h), (k), (l), 
(m), (n), and (o) of this AD. Except as required by paragraph (q) of 
this AD, do the actions at the time specified in paragraph 1.E., 
``Compliance,'' of Boeing Alert Service Bulletin 737-53A1262, dated 
December 9, 2004, except as required by paragraph (j) of this AD. 
Acceptable inspection exemptions are described in paragraph 1.E.1. 
of Boeing Alert Service Bulletin 737-53A1262, dated December 9, 
2004.
    (1) If no scribe line is found, no further work is required by 
this paragraph.
    (2) If any scribe line is found: Do all applicable investigative 
and corrective actions at the time specified in paragraph 1.E. of 
Boeing Alert Service Bulletin 737-53A1262, dated December 9, 2004, 
by doing all applicable actions specified in Boeing

[[Page 10662]]

Alert Service Bulletin 737-53A1262, dated December 9, 2004, except 
as required by paragraph (i) of this AD.

    Note 1: A detailed inspection is defined in Note 10 of Boeing 
Alert Service Bulletin 737-53A1262, dated December 9, 2004, under 
paragraph 3.A., ``General Information.'' Specific magnification 
requirements may be specified in the steps of the Work Instructions.

Exceptions to and Clarification of Service Bulletin 737-53A1262 
Procedures

    (h) Paragraph (g) of this AD requires accomplishment of Parts 1 
through 11 of Boeing Alert Service Bulletin 737-53A1262, dated 
December 9, 2004. Parts 12 and 13 of Boeing Alert Service Bulletin 
737-53A1262, dated December 9, 2004, may be accomplished, if 
applicable, to allow temporary return to service. This AD does not 
require accomplishment of Part 14 of Boeing Alert Service Bulletin 
737-53A1262, dated December 9, 2004, although the FAA-approved 
procedures described in Part 14 are acceptable for continued 
operation with scribe lines found before the applicable compliance 
time.
    (i) If any scribe line or crack is found during any inspection 
required by paragraph (g) of this AD, and Boeing Alert Service 
Bulletin 737-53A1262, dated December 9, 2004, specifies to contact 
Boeing for appropriate action: Before further flight, inspect or 
repair scribe lines and repair cracks using a method approved in 
accordance with the procedures specified in paragraph (y) of this 
AD.
    (j) Where Boeing Alert Service Bulletin 737-53A1262, dated 
December 9, 2004, specifies a compliance time after the issuance of 
that service bulletin, this AD requires compliance within the 
specified compliance time after May 5, 2006 (the effective date of 
AD 2006-07-12).
    (k) Certain figures are incorrectly identified in Boeing Alert 
Service Bulletin 737-53A1262, dated December 9, 2004. The figure 
cited in Part 8, step 3, should be Figure 39, not Figure 38. The 
figure cited in Part 9, step 4, should be Figure 38, not Figure 39.
    (l) If the operator's records show that the airplane has never 
been stripped and repainted under the dorsal fin fairing since 
delivery from The Boeing Company, then this AD does not require 
inspections of the butt joint, lap joint, and repair, as specified 
in paragraph (g) of this AD, in the areas under the dorsal fin 
fairing.
    (m) Figure 37 of Boeing Alert Service Bulletin 737-53A1262, 
dated December 9, 2004, defines ``Restricted Zones'' at door cutouts 
as the only affected structure. Paragraph (g) of this AD considers 
this area to also include Zone 1B.
    (n) In Figure 1, sheets 2 and 3, of Boeing Alert Service 
Bulletin 737-53A1262, dated December 9, 2004, the first condition 
for the initial compliance threshold for Areas B, C, and E is for 
areas where the cutout modification shown in Boeing Service Bulletin 
737-53A1177 was accomplished. Paragraph (g) of this AD considers 
this condition to also include Zone 1B.
    (o) In Figure 1, sheets 2 and 3, of Boeing Alert Service 
Bulletin 737-53A1262, dated December 9, 2004, the second condition 
for the initial compliance threshold for Areas B, C, and E is for 
areas where the cutout modification shown in Boeing Service Bulletin 
737-53A1177 was not accomplished. Paragraph (g) of this AD considers 
this condition to apply only to Zone 1A.

Reporting Requirement

    (p) For airplanes on which inspections have been done in 
accordance with Boeing Alert Service Bulletin 737-53A1262, dated 
December 9, 2004: At the applicable time specified in paragraph 
(p)(1) or (p)(2) of this AD, submit a report of positive findings of 
cracks found during the inspection required by paragraph (g) of this 
AD to the Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, 
Washington 98124-2207. Alternatively, operators may submit reports 
to their Boeing Company field service representatives. The report 
shall contain, as a minimum, the following information: Airplane 
serial number, flight cycles at time of discovery, location(s) and 
extent of positive crack findings. Under the provisions of the 
Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.), the Office 
of Management and Budget (OMB) has approved the information 
collection requirements contained in this AD and has assigned OMB 
Control Number 2120-0056.
    (1) If the inspection was done before May 5, 2006: Send the 
report within 30 days after May 5, 2006.
    (2) If the inspection was done after May 5, 2006: Send the 
report within 30 days after the inspection is done.

New Requirements of This AD

Inspection

    (q) As of the effective date of this AD, the actions for Zones 
1, 2, and 3, as specified in paragraph (g) of this AD, must be done 
in accordance with the Accomplishment Instructions of Boeing Alert 
Service Bulletin 737-53A1262, Revision 3, dated October 16, 2008, 
and at the applicable times specified in paragraph 1.E., 
``Compliance,'' of Boeing Alert Service Bulletin 737-53A1262, 
Revision 3, dated October 16, 2008, except as specified in paragraph 
(s) of this AD.

    Note 2:  Paragraph 1.E.5. of Boeing Alert Service Bulletin 737-
53A1262, Revision 3, dated October 16, 2008, provides a grace period 
for airplanes that have exceeded the revised thresholds.

Inspection of Zones 4 and 5

    (r) Do a detailed inspection for scribe lines and cracks in 
Zones 4 and 5, as specified in Boeing Alert Service Bulletin 737-
53A1262, Revision 3, dated October 16, 2008. Except as provided by 
paragraph (s) of this AD, do the actions in accordance with the 
Accomplishment Instructions of Boeing Alert Service Bulletin 737-
53A1262, Revision 3, dated October 16, 2008, and at the applicable 
time specified in paragraph 1.E., ``Compliance,'' of Boeing Alert 
Service Bulletin 737-53A1262, Revision 3, dated October 16, 2008, or 
within 4,500 flight cycles after the effective date of this AD, 
whichever occurs later.
    (1) If no scribe line or crack is found: No further work is 
required by this paragraph.
    (2) If any scribe line or crack is found: Do all applicable 
investigative and corrective actions at the time specified in 
paragraph 1.E. of Boeing Alert Service Bulletin 737-53A1262, 
Revision 3, dated October 16, 2008, by doing all applicable actions 
specified in the Accomplishment Instructions of Boeing Alert Service 
Bulletin 737-53A1262, Revision 3, dated October 16, 2008, except as 
required by paragraph (s)(1) of this AD.

Exceptions to Specifications of Boeing Alert Service Bulletin 737-
53A1262, Revision 3, dated October 16, 2008

    (s) The following exceptions to Boeing Alert Service Bulletin 
737-53A1262, Revision 3, dated October 16, 2008, apply to this AD:
    (1) If any scribe line or crack is found during any inspection 
required by this AD, and Boeing Alert Service Bulletin 737-53A1262, 
Revision 3, dated October 16, 2008, specifies to contact The Boeing 
Company for appropriate action: Before further flight, inspect or 
repair scribe lines and repair cracks using a method approved in 
accordance with the procedures specified in paragraph (y) of this 
AD.
    (2) Where Boeing Alert Service Bulletin 737-53A1262, Revision 3, 
dated October 16, 2008, specifies a compliance time after the 
issuance of that service bulletin, this AD requires compliance 
within the specified compliance time after the effective date of 
this AD.
    (3) If the operator's records show that the airplane has never 
been stripped and repainted under the dorsal fin fairing since 
delivery from The Boeing Company, then this AD does not require 
inspections of the butt joint, lap joint, and repair, as specified 
in paragraphs (g), (q), and (r) of this AD, in the areas under the 
dorsal fin fairing.
    (4) For airplanes in Groups 3 and 29, as identified in Boeing 
Alert Service Bulletin 737-53A1262, Revision 3, dated October 16, 
2008: At the applicable times specified in paragraphs (s)(4)(i), 
(s)(4)(ii), and (s)(4)(iii) of this AD, perform a detailed 
inspection for scribe lines and cracks on the main cargo door along 
the lower edge of the upper hinge, around external repairs, and 
around decals, in accordance with the Accomplishment Instructions of 
Boeing Alert Service Bulletin 737-53A1262, Revision 3, dated October 
16, 2008, except as provided by paragraph (s)(4)(iv) of this AD, or 
using a method approved in accordance with the procedures specified 
in paragraph (y) of this AD. If no scribe line or crack is found, no 
further work is required by this paragraph. If any scribe line or 
crack is found, do all applicable related investigative and 
corrective actions at the time specified in paragraph 1.E. of Boeing 
Alert Service Bulletin 737-53A1262, Revision 3, dated October 16, 
2008, by doing all applicable actions specified in the 
Accomplishment Instructions of Boeing Alert Service Bulletin 737-
53A1262, Revision 3, dated October 16, 2008, except as required by 
paragraphs (s)(1), (s)(2), and (s)(3) of this AD.
    (i) For areas along the lower edge of the door hinge from body 
station (BS) 360 to BS 500, the initial compliance threshold is to 
be determined using Zone 1B.

[[Page 10663]]

    (ii) For external repairs, the initial compliance threshold is 
to be determined using Zone 1B.
    (iii) For decals, the initial compliance threshold is to be 
determined using Zone 2.
    (iv) When accomplishing scribe line inspections along the lower 
edge of the main cargo door hinge, consider the hinge-to-skin detail 
inspection to be equivalent to a lap joint detail inspection and use 
the lap joint inspection methods in accordance with Boeing Alert 
Service Bulletin 737-53A1262, Revision 3, dated October 16, 2008.
    (5) For Group 11 airplanes, as specified in Boeing Alert Service 
Bulletin 737-53A1262, Revision 3, dated October 16, 2008: Stringer 
20R between BS 727C and BS 727D+10 is in Zone 1B.

Actions Accomplished in Accordance With Previous Service 
Information

    (t)(1) Actions accomplished before the effective date of this AD 
in accordance with Boeing Alert Service Bulletin 737-53A1262, dated 
December 9, 2004, are acceptable for compliance with the 
corresponding requirements of paragraphs (q) and (r) of this AD.
    (2) Actions accomplished before the effective date of this AD in 
accordance with Boeing Service Bulletin 737-53A1262, Revision 1, 
dated March 1, 2007; or Revision 2, dated September 20, 2007; are 
acceptable for compliance with the corresponding requirements of 
paragraphs (g), (q), and (r) of this AD.

Clarification of Procedures in the Service Bulletin

    (u) For airplanes on which inspections are done as of the 
effective date of this AD: This AD requires accomplishment of Parts 
1 through 11, 15, and 16 of the Accomplishment Instructions of 
Boeing Alert Service Bulletin 737-53A1262, Revision 3, dated October 
16, 2008. Parts 12 and 13 of the Accomplishment Instructions of 
Boeing Alert Service Bulletin 737-53A1262, Revision 3, dated October 
16, 2008, may be accomplished, if applicable, to allow temporary 
return to service. This AD does not require accomplishment of Part 
14 of the Accomplishment Instructions of Boeing Alert Service 
Bulletin 737-53A1262, Revision 3, dated October 16, 2008, although 
the FAA-approved procedures described in Part 14 are acceptable for 
continued operation with scribe lines found before the applicable 
compliance time.

Report

    (v) For airplanes on which inspections are done in accordance 
with the service information identified in Table 1 of this AD: At 
the applicable time specified in paragraph (v)(1) or (v)(2) of this 
AD, submit a report of positive findings of cracks found during the 
inspections required by paragraphs (q), (r), and (s)(4) of this AD 
to the Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, 
Washington 98124-2207. Alternatively, operators may submit reports 
to their Boeing Company field service representatives. The report 
must contain, as a minimum, the following information: airplane 
serial number, flight cycles at time of discovery, location(s) and 
extent of positive crack findings. Under the provisions of the 
Paperwork Reduction Act (44 U.S.C. 3501 et seq.), the Office of 
Management and Budget (OMB) has approved the information collection 
requirements contained in this AD and has assigned OMB Control 
Number 2120-0056.
    (1) For an inspection done before the effective date of this AD: 
Send the report within 30 days after the effective date of this AD.
    (2) For an inspection done after the effective date of this AD: 
Send the report within 30 days after the inspection is done.

                      Table 1--Service Information
------------------------------------------------------------------------
 Boeing Service Information      Revision                Date
------------------------------------------------------------------------
Boeing Alert Service                       3  October 16, 2008.
 Bulletin 737-53A1262.
Boeing Service Bulletin 737-               1  March 1, 2007.
 53A1262.
Boeing Service Bulletin 737-               2  September 20, 2007.
 53A1262.
------------------------------------------------------------------------

Repair Plan in Lieu of Required Inspections

    (w) A repair plan approved by a Boeing Company Authorized 
Representative or Designated Engineering Representative before the 
effective date of this AD is acceptable for compliance with the 
requirements of paragraphs (g)(2), (i), (q), (r), (s)(1), and (s)(4) 
of this AD, provided the approval was documented via FAA Form 8110-3 
or 8100-9, and scribe line damage identified in the title of the 
form.

Exceptions and Clarification

    (x) Paragraph 12.a.(2) of Part 12 of the Accomplishment 
Instructions of Boeing Service Bulletin 737-53A1262, Revision 1, 
dated March 1, 2007; Revision 2, dated September 20, 2007; and 
Boeing Alert Service Bulletin 737-53A1262, Revision 3, dated October 
16, 2008; specifies internal inspections in accordance with Boeing 
Service Bulletin 737-53-1179, Revision 2, dated October 25, 2001, 
except for airplanes inspected internally in accordance with 
paragraph (b) of AD 2003-14-06, Amendment 39-13225. Inspections 
accomplished in accordance with AMOCs previously approved to 
paragraph (b) of AD 2003-14-06, are approved as an acceptable 
alternative method of compliance to the internal inspections 
specified in Part 12 of Boeing Alert Service Bulletin 737-53A1262, 
Revision 1, dated March 1, 2007; Revision 2, dated September 20, 
2007; and Revision 3, dated October 16, 2008.

Alternative Methods of Compliance (AMOCs)

    (y)(1) The Manager, Seattle Aircraft Certification Office (ACO), 
FAA, has the authority to approve AMOCs for this AD, if requested in 
accordance with the procedures found in 14 CFR 39.19. Send 
information to ATTN: Wayne Lockett, Aerospace Engineer, Airframe 
Branch, ANM-120S, FAA, Seattle ACO, 1601 Lind Avenue, SW., Renton, 
Washington 98057-3356; telephone (425) 917-6447; fax (425) 917-6590. 
Or, e-mail information to 9-ANM-Seattle-ACO-AMOC-Requests@faa.gov.
    (2) To request a different method of compliance or a different 
compliance time for this AD, follow the procedures in 14 CFR 39.19. 
Before using any approved AMOC on any airplane to which the AMOC 
applies, notify your principal maintenance inspector (PMI) or 
principal avionics inspector (PAI), as appropriate, or lacking a 
principal inspector, your local Flight Standards District Office. 
The AMOC approval letter must specifically reference this AD.
    (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.

Material Incorporated by Reference

    (z) You must use Boeing Alert Service Bulletin 737-53A1262, 
Revision 3, dated October 16, 2008; to do the actions required by 
this AD, unless the AD specifies otherwise.
    (1) The Director of the Federal Register approved the 
incorporation by reference of Boeing Alert Service Bulletin 737-
53A1262, Revision 3, dated October 16, 2008, under 5 U.S.C. 552(a) 
and 1 CFR part 51.
    (2) 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 
me.boecom@boeing.com; Internet https://www.myboeingfleet.com.
    (3) You may review copies of the 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 or 425-227-1152.
    (4) 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

[[Page 10664]]

material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

    Issued in Renton, Washington, on February 24, 2010.
Jeffrey E. Duven,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2010-4511 Filed 3-8-10; 8:45 am]
BILLING CODE 4910-13-P
```