```

[Federal Register Volume 75, Number 248 (Tuesday, December 28, 2010)]
[Rules and Regulations]
[Pages 81412-81417]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2010-31899]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2009-0913; Directorate Identifier 2009-NM-101-AD; 
Amendment 39-16545; AD 2010-26-06]
RIN 2120-AA64

Airworthiness Directives; The Boeing Company Model 737-600, -700, 
-700C, -800, and -900 Series Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: We are adopting a new airworthiness directive (AD) for certain 
Model 737-600, -700, -700C, -800, and -900 series airplanes. This AD 
requires inspections for scribe lines in the fuselage skin at lap 
joints, the splice strap at certain butt joints, the skin or doubler at 
certain approved repair doublers, and the skin at decal locations; and 
related investigative and corrective actions if necessary. This AD 
results from reports of scribe line damage found adjacent to the skin 
lap joints, decals, and wing-to-body fairings. We are issuing this AD 
to detect and correct scribe lines, which can develop into fatigue 
cracks in the skin. Undetected fatigue cracks can grow and cause sudden 
decompression of the airplane.

DATES: This AD is effective February 1, 2011.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in the AD as of February 1, 
2011.

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.
    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,

[[Page 81413]]

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, 
1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 
917-6447; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

Discussion

    We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR 
part 39 to include an airworthiness directive (AD) that would apply to 
certain Model 737-600, -700, -700C, -800, and -900 series airplanes. 
That NPRM was published in the Federal Register on October 19, 2009 (74 
FR 53442). That NPRM proposed to require inspections for scribe lines 
in the fuselage skin at lap joints, the splice strap at certain butt 
joints, the skin or doubler at certain approved repair doublers, and 
the skin at decal locations; and related investigative and corrective 
actions, if necessary.

Comments

    We gave the public the opportunity to participate in developing 
this AD. We considered the comments received from the commenters.

Support for the NPRM

    The National Safety Transportation Board (NTSB) and Air Transport 
Association (ATA), on behalf of its member AirTran, support the intent 
of the NPRM.

Request To Refer to Latest Revision of Service Bulletin

    The Boeing Company requests that we revise the NPRM to refer to the 
latest version of the appropriate service information, Boeing Service 
Bulletin 737-53A1289, Revision 1, dated November 18, 2009.
    We agree to refer to the latest version of the service information. 
Boeing Service Bulletin 737-53A1289, Revision 1, dated November 18, 
2009, shows changes of airplane operators in Paragraph 1.A., 
Effectivity, and clarifies requirements for inspections of areas of the 
fuselage having decals. Boeing Service Bulletin 737-53A1289, Revision 
1, dated November 18, 2009, does not require additional work beyond the 
original version of that service bulletin, which was cited as the 
appropriate source of service information in the NPRM. We have revised 
the AD requirements to refer to Boeing Service Bulletin 737-53A1289, 
Revision 1, dated November 18, 2009, as the appropriate source of 
service information, and we have added paragraph (h) to this final rule 
to provide credit for actions performed in accordance with Boeing Alert 
Service Bulletin 737-53A1289, dated January 14, 2009.

Request To Update Exception in Note 1 of the NPRM

    The Boeing Company requests that we revise the NPRM to update the 
exception referenced in Note 1 of the NPRM because Boeing Service 
Bulletin 737-53A1289, Revision 1, dated November 18, 2009, adds an 
exception to the inspections. The additional exception is described in 
subparagraph 1.f. in paragraph 1.E., ``Compliance,'' of that service 
bulletin. Southwest Airlines also requests that we add the same 
provision. Southwest notes that the additional provision states, ``If 
the operator's records show that decal installation and removal 
procedures were used, at all times since delivery, which included pre-
cutting decals prior to installation on the airplane and no use of 
metallic tooling of any kind during the installation or removal of 
decals on the airplane, then the [decal] inspections [per Tables 5 
through 9] are not required.''
    We agree. The specified decal installation and removal procedures 
have been shown to not result in scribe damage to the fuselage. We have 
updated Note 1 in this AD to include the additional exception specified 
in subparagraph 1.f. in paragraph 1.E., ``Compliance,'' of Boeing 
Service Bulletin 737-53A1289, Revision 1, dated November 18, 2009.

Request To Include Training About Scribe Lines and Scratches

    The National Transportation Safety Board (NTSB) is concerned that 
the NPRM does not address the underlying condition that mechanics and 
technicians do not have the knowledge, training, and awareness to 
recognize that minor damage to pressurized airplane skin can result in 
fatigue cracking, which can result in depressurization events. The NTSB 
requests that the FAA reexamine existing maintenance practices and 
training techniques to educate personnel about the serious consequences 
of minor scratches and scribe lines on pressurized fuselage skin 
panels.
    We acknowledge the NTSB's concerns. However, such training is 
outside the scope of the AD requirements as defined in 14 CFR part 39. 
(Part 12 provides inspection procedures for scribe marks found before 
the initial inspection.) We have worked with industry groups and 
manufacturers to increase awareness of scribe lines and their effects 
on skin panels. This topic has also been addressed at Industry Steering 
Committee (ISC), Maintenance Steering Group (MSG), and Structures Task 
Group (STG) meetings. We have not changed the AD in regard to this 
issue.

Request To Remove Hard Time Date

    Continental Airlines (Continental) requests that we review the hard 
time date of July 1, 2007, that is stated in ``Compliance,'' paragraph 
1.E.1(a) through 1.E.1(e) of Boeing Alert Service Bulletin 737-53A1289, 
dated January 14, 2009. Continental states that a hard time date should 
not matter if the operator can provide documents that show sealant and 
decals were removed using an approved method after the operator 
received the airplane.
    We have reviewed the hard time date, as requested by the commenter. 
The date of July 1, 2007, was selected because all the Boeing 
documentation was revised as of this date to detail the proper method 
for removing paint, sealant, and decals. Not all operators may have 
used methods equivalent to the methods stated in this documentation, 
but they may have used methods detailed in documentation published 
before this date. As a result, the date of July 1, 2007, is included 
appropriately in Boeing Service Bulletin 737-53A1289, Revision 1, dated 
November 18, 2009. Operators may submit a request for approval of an 
alternative method of compliance (AMOC) if their methods for removing 
paint, sealant, and decals were implemented before July 1, 2007, and 
provide an acceptable level of safety. We have not changed the AD in 
regard to this issue.

Request To Incorporate Instructions into Structural Repair Manual (SRM)

    Continental requests that the instructions given in Part 12 of the 
work instructions of Boeing Alert Service Bulletin 737-53A1289, dated 
January 14, 2009, be incorporated into the structural repair manual 
(SRM) before the release of the AD because the SRM is for non-routine 
or non-scheduled events. (Part 12 provides inspection procedures for 
scribe marks found before the initial inspection.) Continental states 
that the current instructions make it difficult to comply with the NPRM 
by the operators' mechanics because they would use the SRM only for 
repair to damages that are discovered or that occurred during a non-
routine event.

[[Page 81414]]

    We disagree with the request. Significant effort has been made to 
educate operators about the effects of scribe lines on the fuselage 
structure. Therefore, all mechanics should be aware of scribe lines. 
Also, the service bulletins pertaining to scribe lines for all Boeing 
models contain instructions for repairing scribe line damage found 
before the inspection threshold. We have not changed the AD in regard 
to this issue.

Request To Allow All Repairs Using the SRM

    Continental requests that we revise the NPRM to allow all repairs 
using the SRM. Continental states that it does not agree that all 
repairs need to be approved by Boeing or the FAA Seattle Aircraft 
Certification Office, as specified in Boeing Alert Service Bulletin 
737-53A1289, dated January 14, 2009, and in paragraphs (i) and (k) of 
the NPRM. Continental proposes that we add an exception to Boeing Alert 
Service Bulletin 737-53A1289, dated January 14, 2009, to allow all 
repairs other than repairs done for the Limited Return to Service 
(LTRS) program to be accomplished in accordance with the SRM or to be 
FAA-approved.
    Continental states because the scribe lines do not result from a 
design deficiency, no differences exist between these repairs and any 
other repairs on the airplanes. Continental states that if such an 
exception is not allowed, operators are unfairly penalized by being 
forced to use Boeing's repair services. While Continental acknowledges 
that paragraph (k)(2) of the NPRM (now paragraph (p)(2) of the final 
rule) allows requests for AMOC approvals, it states that the FAA's 
response time to approve AMOCs does not allow airplanes to return to 
service in a timely manner that supports operational requirements. 
Continental states that this is why the designee program exists as 
given in section 183.29 of the Federal Aviation Regulations (14 CFR 
183.29) and FAA Order 8100.15, which should not be overridden by the 
proposed AD.
    We agree to revise the final rule to add an exception to the 
accomplishment instructions specified by Boeing Service Bulletin 737-
53A1289, Revision 1, dated November 18, 2009. We agree that repairs to 
the fuselage where the scribe line is removed are not different from 
other repairs to the airplane. Also, Boeing has revised the Allowable 
Damage section of the SRM to address scribe line damage. We have added 
a new paragraph (k) to the final rule to allow for repair in accordance 
with an FAA-approved method. We have also added Note 2 to the final 
rule that provides guidance for repairing scribe damage.

Request To Correct ``Relevant Service Information'' in NPRM

    Continental requests that we correct the ``Relevant Service 
Information'' section in the NPRM because Boeing Alert Service Bulletin 
737-53A1289, dated January 14, 2009, does not specify final repairs by 
using the SRM. Instead, Continental states that Boeing Alert Service 
Bulletin 737-53A1289, dated January 14, 2009, specifies to contact 
Boeing for final repairs.
    We agree. However, this section does not appear in this final rule. 
We have not changed the AD in regard to this issue.

Request To Revise Exceptions for Airplanes That Have Been Scuff Sanded

    Air Transport Association (ATA), on behalf of its member American 
Airlines (American), states that the list of exceptions in section 1.E, 
``Compliance,'' of Boeing Alert Service Bulletin 737-53A1289, dated 
January 14, 2009, should be revised to specify that airplanes that have 
been scuff sanded and repainted do not require inspections in areas 
where they have been repainted. American states that it does not use 
complete paint on the external surfaces and leaves most of the fuselage 
in natural metal finish. American states that it rarely accomplishes a 
chemical strip of the painted stripes and that the sealant can be 
damaged by chemical strippers. This process does not require removal 
and reapplication, which might cause scribe marks.
    We partially agree. The operator's unique finish on the fuselage 
limits the potential for the development of scribe lines. However, we 
do not agree that changing this AD is necessary because operators may 
interpret such an exception to allow sanding after paint and sealant 
are removed, and these methods might eliminate any evidence of scribe 
marks. Operators may submit requests for approval of an AMOC for their 
particular finish configuration. We have not changed the AD in regard 
to this issue.

Request To Revise Costs of Compliance

    ATA, on behalf of its members Air Tran Airlines (Air Tran) and 
American, requests that we revise the costs of compliance. AirTran 
states that complying with the NPRM would cost $2,500 per airplane and 
that it would have to procure special tooling for each site performing 
the inspection. American Airlines states that complying with the NPRM 
without any changes would cost it $1,004,080 for labor and $3,458,455 
for additional out-of-service time.
    We have revised the costs of compliance to increase the labor rate 
from $80 to $85. However, we have not changed the costs of compliance 
otherwise. The cost information below describes only the direct costs 
of the specific actions required by this AD. Based on the best data 
available, the manufacturer provided the number of work hours necessary 
to do the required actions. This number represents the time necessary 
to perform only the actions actually required by this AD. We recognize 
that, in doing the actions required by an AD, operators might incur 
incidental costs in addition to the direct costs. The cost analysis in 
AD rulemaking actions, however, typically does not include incidental 
costs such as the time required to gain access and close up, time 
necessary for planning, or time necessitated by other administrative 
actions. Those incidental costs, which might vary significantly among 
operators, are almost impossible to calculate.

Request To Require Reporting of Only Positive Findings of Cracks

    Southwest Airlines (Southwest) and Qantas request that we revise 
the AD to require reporting of only crack findings. Southwest notes 
that AD 2006-07-12, Amendment 39-14539 (71 FR 16211, March 31, 2006), a 
similar AD that requires inspection for scribe lines on Model 737 
airplanes, requires the reporting of cracks found only during LRTS 
inspections, not scribe lines found as a result of the initial scribe 
inspections. Qantas asks why a report for a one-time inspection is 
required.
    We agree to provide clarification of the rationale for reporting 
requirements and to revise the reporting requirements. The data will be 
used to determine if the existing inspection thresholds and the repeat 
inspection intervals provided in the LRTS program may be increased, 
which may result in less work for operators in the future. We have 
revised paragraph (o) of this final rule to require reporting only 
positive findings of cracks found during any inspections required by 
this AD.

Request To Add Instructions for Addressing Scribe Lines Outside Zones

    Southwest requests that we revise the AD to either state how to 
address scribe lines found in zones outside of those zones specified in 
Boeing Alert Service Bulletin 737-53A1289, dated January 14, 2009, or 
add a statement that ``no

[[Page 81415]]

zone'' scribes do not require repetitive inspections or terminating 
actions. Southwest did not provide justification for its request.
    We disagree that revising the NPRM is necessary. This AD requires 
inspections and a terminating action in only the zones identified in 
Boeing Service Bulletin 737-53A1289, Revision 1, dated November 18, 
2009. Any zone that is not identified in Boeing Service Bulletin 737-
53A1289, Revision 1, dated November 18, 2009, is not subject to 
inspection or repair requirements of this rule. (See paragraph 3.A. 
Note 13 of Boeing Service Bulletin 737-53A1289, Revision 1, dated 
November 18, 2009.) We have not changed the AD in regard to this issue.

Request To Address Scribe Lines Less than 0.001 Inch Deep

    Southwest requests that we revise the AD to address scribe lines 
that are less than 0.001 inch deep. Southwest states that Boeing Alert 
Service Bulletin 737-53A1289, dated January 14, 2009, states that no 
further inspections are required for such scribe lines, but Southwest 
requests that the AD specifically state that such lines do not require 
terminating action. Southwest asks why the compliance time is ``before 
further flight'' if no inspections are required. Southwest asks if that 
means no additional NDT inspections are required at the time of finding 
such lines.
    We partially agree with the commenter's request. The compliance 
table in paragraph 1.E., ``Compliance,'' of the service bulletin 
requires clarification as it shows the compliance time of ``before 
further flight'' for inspecting scribe lines that are less than 0.001 
inch deep. We have clarified this issue by stating in paragraph (m) of 
this AD that no further inspections are required provided that correct 
sealant removal procedures are used.

Request To Allow the Blending of Scribe Lines

    Southwest requests that we revise the AD to allow operators to 
blend scribe lines in accordance with the SRM by treating the scribe 
line as a gouge or scratch. Southwest states that the 737-700 SRM does 
not address scribe lines in the Allowable Damage section. Southwest 
states that Boeing Service Bulletin 737-53A1262 (the appropriate source 
of service information for 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 in AD 2006-07-12, Amendment 
39-14539 (71 FR 16211, March 31, 2006)) allows the blending of scribe 
lines in accordance with the SRM by treating the scribe line as a gouge 
or scratch. However, Southwest notes, Boeing Alert Service Bulletin 
737-53A1289, dated January 14, 2009, does not allow for the same 
treatment, but recommends that operators contact Boeing for repair 
instructions.
    We agree. All Boeing Model 737 SRMs were revised as a result of the 
scribe issue to address scribe damage in butt joints and within 1.0 
inch of lap splice lower edges and external repair edges. This 
information is found in the Allowable Damage sections of the SRMs. We 
have added Note 2 to this final rule, as noted previously.

Request To Include Terminating Action for Repairing Scribe Lines

    Southwest requests that accomplishing repairs or modifications in 
accordance with Boeing Service Bulletin 737-53-1232 be an approved 
method for terminating scribe line inspections. Southwest did not 
provide any justification for its request.
    We disagree. The repair and modification specified in Boeing 
Service Bulletin 737-53-1232 are specifically designed for chem mill 
step cracking, not scribe lines. The modification specified in Boeing 
Service Bulletin 737-53-1232 would not meet the requirements of this 
AD. The modification provided in Boeing Service Bulletin 737-53A1289, 
Revision 1, dated November 18, 2009, does not extend a minimum of three 
fastener rows below any scribe line damage at a lap joint, and the 
doubler and tripler used on the repair specified in Boeing Service 
Bulletin 737-53A1289, Revision 1, dated November 18, 2009, do not 
extend a minimum of three fastener rows below any scribe damage at a 
lap joint. We have not changed the AD in regard to this issue.

Request To Include an Exception for Inspections of Areas Covered by 
Certain Repairs

    Southwest requests that we revise the NPRM to contain a provision 
excluding inspections of areas that are covered by repairs that span a 
minimum of three rows above and below the inspection area.
    We agree with the commenter. This exception is provided in other 
scribe line ADs for other Boeing airplane models and should apply in 
this AD as well. We have added paragraph (l) to this AD to provide this 
exception to Boeing Service Bulletin 737-53A1289, Revision 1, dated 
November 18, 2009. In addition, we have also added an exception to not 
require removal of a repair even if it does not span a potential scribe 
by 3 or more fastener rows and there is no evidence of scribe lines 
within 10 inches of the repair.

Request To Include Exception for Inspections of Areas Under the Dorsal 
Fin Fairing

    Southwest requests that we include an exception for inspections of 
areas under the dorsal fin fairing. Southwest requests that this area 
be treated the same as the wing-to-body fairing, i.e., if the area 
under the dorsal fin fairing has never been stripped or repainted since 
delivery, then the scribe line inspection should not be required in 
that area.
    We agree. We have added paragraph (n) of this final rule to provide 
an exception for this area.

Request for Clarification of the Compliance Time

    Qantas states since a scribe line can occur at any time during the 
service life of an airplane and at many locations, this program uses 
both total flight cycles and structural criticality of location to 
determine the inspection requirements. Qantas asks if the compliance 
time takes into account scribe lines induced before the first 
repainting of the airplane.
    We agree to provide clarification. The compliance times specified 
in Boeing Service Bulletin 737-53A1289, Revision 1, dated November 18, 
2009, do not account for scribe lines induced before the first 
repainting. All analysis was accomplished using the assumption that 
scribe lines might be induced during repainting only when the sealant 
is removed from lap and butt joints and around external doublers. The 
FAA has received no prior reports of scribe line damage on Model 737NG 
airplanes before the first repainting. We will investigate the reports 
provided by the commenter and all operators, and will take action as 
necessary. We have not changed the AD in regard to this issue.

Request To Omit Instructions for Restoring the Surface Finish

    ATA, on behalf of its member American, requests that we do not 
consider as part of the AD the methodology in Part 11--``Surface Finish 
Restoration'' of Boeing Alert Service Bulletin 737-53A1289, dated 
January 14, 2009. American states that it has internal processes that 
meet the intent of the requirement for the reapplication of removed 
finishes, although those processes may not be identical in material, 
workflow, or processes.
    We partially agree with the commenter. While the unique finishes on 
the fuselage may warrant using different processes than those used on a

[[Page 81416]]

typical fuselage, we disagree with the request because the commenter 
did not provide details on the processes that meet the intent of the 
AD. We will consider requests for an approval of an AMOC if data 
demonstrate that it meets an acceptable level of safety. We did not 
change the AD in regard to this issue.

Explanation of Changes Made to This AD

    We have revised the ``Alternative Methods of Compliance (AMOCs)'' 
paragraph in this AD to clarify the delegation authority for the Boeing 
Commercial Airplanes Organization Designation Authorization. We have 
also revised paragraph (k) of this final rule to clarify that repairs 
must be made in accordance with an FAA-approved method.

Explanation of Change to Applicability

    We have revised the applicability of the existing AD to identify 
model designations as published in the most recent type certificate 
data sheet for the affected models.

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. We also determined that 
these changes will not increase the economic burden on any operator or 
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

    We estimate that this AD affects 782 airplanes of U.S. registry. 
The following table provides the estimated costs for U.S. operators to 
comply with this AD.

                                                                 Table--Estimated Costs
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                    Number of U.S.-
             Action                   Work hours      Average labor rate         Parts         Cost per product       registered          Fleet cost
                                                           per hour                                                    airplanes
--------------------------------------------------------------------------------------------------------------------------------------------------------
Inspection......................                  53                 $85                  $0  $4,505 per                         782  $3,522,910 per
                                                                                               inspection cycle.                       inspection cycle.
--------------------------------------------------------------------------------------------------------------------------------------------------------

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

    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.
    You can find our regulatory evaluation and the estimated costs of 
compliance in the AD Docket.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

0
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 adding the following new AD:

2010-26-06 The Boeing Company: Amendment 39-16545. Docket No. FAA-
2009-0913; Directorate Identifier 2009-NM-101-AD.

Effective Date

    (a) This airworthiness directive (AD) is effective February 1, 
2011.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to The Boeing Company Model 737-600, -700, -
700C, -800, and -900 series airplanes, certificated in any category, 
as identified in Boeing Service Bulletin 737-53A1289, Revision 1, 
dated November 18, 2009.

Subject

    (d) Air Transport Association (ATA) of America Code 53: 
Fuselage.

Unsafe Condition

    (e) This AD results from reports of scribe line damage found 
adjacent to the skin lap joints, decals, and wing-to-body fairings. 
The Federal Aviation Administration is issuing this AD to detect and 
correct scribe lines, which can develop into fatigue cracks in the 
skin. Undetected fatigue cracks can grow and cause sudden 
decompression of the airplane.

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.

Inspection

    (g) At the applicable times specified in paragraph 1.E., 
``Compliance,'' of Boeing Service Bulletin 737-53A1289, Revision 1, 
dated November 18, 2009 (``the service bulletin''), except as 
provided in paragraph (i) of this AD, do detailed external 
inspections for scribe lines in the fuselage skin at lap joints, the 
splice strap at certain butt joints, the skin or doubler at certain 
approved repair doublers, and the skin at decals; and do all 
applicable related investigative and corrective actions, by 
accomplishing all

[[Page 81417]]

actions specified in the Accomplishment Instructions of the service 
bulletin, except as provided by paragraphs (j), (k), (l), (m), and 
(n) of this AD.

    Note 1: The inspection exceptions described in subparagraphs 
1.a. through 1.f. in paragraph 1.E., ``Compliance,'' of Boeing 
Service Bulletin 737-53A1289, Revision 1, dated November 18, 2009, 
apply to this AD.

Credit for Actions Accomplished According to Previous Issue of Service 
Bulletin

    (h) Actions accomplished before the effective date of this AD 
according to Boeing Alert Service Bulletin 737-53A1289, dated 
January 14, 2009, are considered acceptable for compliance with the 
corresponding actions specified in this AD.

Exceptions to Service Bulletin Specifications

    (i) Where Boeing Service Bulletin 737-53A1289, Revision 1, dated 
November 18, 2009, specifies a compliance time after the date on the 
service bulletin, this AD requires compliance within the specified 
compliance time after the effective date of this AD.
    (j) Where Boeing Service Bulletin 737-53A1289, Revision 1, dated 
November 18, 2009, specifies to contact Boeing for appropriate 
action, accomplish applicable actions using a method approved in 
accordance with the procedures specified in paragraph (p) of this 
AD.
    (k) Where Boeing Service Bulletin 737-53A1289, Revision 1, dated 
November 18, 2009, specifies to contact Boeing for instructions to 
repair scribe lines: Remove the scribe line damage and install a 
reinforcing repair using an FAA-approved method.

    Note 2: Guidance for repairing scribe damage (e.g., nicks, 
gouges, scratches, and corrosion) may be found in the Allowable 
Damage section of the appropriate Boeing 737 Structural Repair 
Manual (SRM).

    Note 3: Operators must obtain an approved damage tolerance 
evaluation for any repair installed to comply with Section 
121.1109(c)(2) or 129.109(c)(2) of the Code of Federal Regulations 
(14 CFR 121.1109(c)(2) or 129.109(c)(2)).

    (l) Inspections are not required in areas where an existing 
repair covers a potential scribe line or where the scribe line is 
within 10 inches of the repair, provided the repair spans a minimum 
of three fastener rows beyond each side of the potential scribe line 
location (perpendicular to the scribe line direction). If a repair 
doubler does not span the potential scribe line location by 3 or 
more fastener rows, but there is no evidence of scribe lines within 
10 inches of the repair, then inspections under the repair are not 
required.
    (m) Where Boeing Service Bulletin 737-53A1289, Revision 1, dated 
November 18, 2009, specifies a compliance time of ``before further 
flight'' for inspecting scribe lines less than 0.001 inch deep for 
cracks, no further inspections are required by paragraph (g) of this 
AD, provided that correct sealant removal procedures are used for 
future work at those locations.
    (n) If records show that the airplane has never been stripped 
and repainted under the dorsal fin fairing since delivery from 
Boeing, then this AD does not require inspections specified in 
paragraph (g) of this AD for the butt joint, lap joint, and repairs 
in the areas under the dorsal fin fairing.

Report

    (o) At the applicable time specified in paragraph (o)(1) or 
(o)(2) of this AD: Submit a report of positive findings of cracks 
found during the inspections required by paragraph (g) of this AD. 
You may use Appendix B of Boeing Service Bulletin 737-53A1289, 
Revision 1, dated November 18, 2009. Send the report to Boeing 
Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207. 
The report must contain, at a minimum, the inspection results, a 
description of any discrepancies found, the airplane serial number, 
and the number of flight cycles and flight hours on the airplane. 
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) If the inspection was done on or after the effective date of 
this AD: Submit the report within 30 days after the inspection.
    (2) If the inspection was done before the effective date of this 
AD: Submit the report within 30 days after the effective date of 
this AD.

Alternative Methods of Compliance (AMOCs)

    (p)(1) The Manager, Seattle Aircraft Certification Office, FAA, 
has the authority to approve AMOCs for this AD, if requested using 
the procedures found in 14 CFR 39.19. Send information to ATTN: 
Wayne Lockett, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, 
Seattle Aircraft Certification Office, 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 an 
Authorized Representative for the Boeing Commercial Airplanes 
Organization Designation Authorization who 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

    (q) You must use Boeing Service Bulletin 737-53A1289, Revision 
1, dated November 18, 2009, 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 this service information 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.
    (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 
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 December 10, 2010.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2010-31899 Filed 12-27-10; 8:45 am]
BILLING CODE 4910-13-P
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