Document ID: FAA-2015-0495-0007
Agency: faa
Document Type: Rule
Title: Airworthiness Directives: The Boeing Company Airplanes
Posted Date: 2016-03-18T04:00Z

[Federal Register Volume 81, Number 53 (Friday, March 18, 2016)]
[Rules and Regulations]
[Pages 14711-14716]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-05842]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2015-0495; Directorate Identifier 2014-NM-172-AD; 
Amendment 39-18435; AD 2016-06-04]
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 adopting a new airworthiness directive (AD) for certain 
The Boeing Company Model 737-300, -400, and -500 series airplanes. This 
AD was prompted by reports of cracking at certain fastener locations in 
the window corners of the window belt area. This AD requires repetitive 
high frequency eddy current (HFEC) inspections for fatigue cracking in 
certain fastener locations in the window corners of the window belt 
area, and related investigative and corrective actions if necessary. 
This AD also provides an optional preventive modification that 
terminates the inspections at the modified location. We are issuing 
this AD to detect and correct fatigue cracking around fastener 
locations that could cause multiple window corner skin cracks, which 
could result in rapid decompression and loss of structural integrity of 
the airplane.

DATES: This AD is effective April 22, 2016.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of April 22, 
2016.

ADDRESSES: For service information identified in this final rule, 
contact Boeing Commercial Airplanes, Attention: Data & Services 
Management, P.O. Box 3707, MC 2H-65, Seattle, WA 98124-2207; telephone 
206-544-5000, extension 1; fax 206-766-5680; Internet https://www.myboeingfleet.com. You may view this referenced service information 
at the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., 
Renton, WA. For information on the availability of this material at the 
FAA, call 425-227-1221. It is also available on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2015-
0495.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2015-
0495; 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 Docket 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: Jennifer Tsakoumakis, Aerospace 
Engineer, Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft 
Certification Office (ACO), 3960 Paramount Boulevard, Lakewood, CA 
90712-4137; phone: 562-627-5264; fax: 562-627-5210; email: 
jennifer.tsakoumakis@faa.gov.

SUPPLEMENTARY INFORMATION:

Discussion

    We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR 
part 39 by adding an AD that would apply to certain The Boeing Company 
Model 737-300, -400, and -500 series airplanes. The NPRM published in 
the Federal Register on March 24, 2015 (80 FR 15523) (``the NPRM''). 
The NPRM was prompted by reports of cracking at certain fastener 
locations in the window corners of the window belt area. The NPRM 
proposed to require repetitive HFEC inspections for fatigue cracking in 
certain fastener locations in the window corners of the window belt 
area, and related investigative and corrective actions if necessary. We 
are issuing this AD to detect and correct fatigue cracking around 
fastener locations that could cause multiple window corner skin cracks, 
which could result in rapid decompression and loss of structural 
integrity of the airplane.

Comments

    We gave the public the opportunity to participate in developing 
this AD. The following presents the comments received on the NPRM and 
the FAA's response to each comment.

Request for Clarification of Location of the Twelve Fastener 
Inspections

    Southwest Airlines (SWA) requested that a correction be made to 
paragraph (g) of the proposed AD to clarify the areas for the 
inspection of the twelve fastener locations. SWA noted that paragraph 
(g) of the proposed AD stated to inspect locations ``at the upper 
forward and lower aft corners of each window between station (STA) 360 
and STA 540 and between STA 727 and STA 908.'' SWA stated that between 
STA 727 and STA 908, Boeing Alert Service Bulletin 737-53A1328, dated 
July 22, 2014, specifies the location as the lower forward and upper 
aft corners.
    We agree with the commenter for the reason provided. We have 
revised paragraph (g) of this AD to require an inspection of the twelve 
fastener locations at the upper forward and lower aft corners of each 
window between STA 360 and STA 540 and at the upper aft and lower 
forward corners of each window between STA 727 and STA 908.

Request for Clarification of the Intent of the Inspection Requirements 
in Paragraph (g) of the Proposed AD

    SWA requested that we clarify the intent of paragraph (g) of the 
proposed AD. SWA stated that paragraph (g) of the proposed AD states to 
accomplish the inspections at the times specified in tables 1 and 2 of 
paragraph 1.E.,

[[Page 14712]]

``Compliance,'' of Boeing Alert Service Bulletin 737-53A1328, dated 
July 22, 2014, and then repeat the inspections at the applicable times 
specified in tables 1 and 2 until ``the terminating action in paragraph 
(h) of this AD is accomplished,'' which is the optional preventive 
modification in Part 3 of the Accomplishment Instructions of Boeing 
Alert Service Bulletin 737-53A1328, dated July 22, 2014. SWA stated 
that, per note (b) in tables 1 and 2, accomplishment of the preventive 
modification in accordance with Boeing Alert Service Bulletin 737-
53A1328, dated July 22, 2014, is terminating action for both the 
initial and repeat inspections at the modified locations. SWA stated 
that paragraph (g) of the proposed AD does not mention the option to 
accomplish the actions specified in paragraph (h) of the proposed AD in 
lieu of the initial inspection specified in paragraph (g) of this AD; 
it only states to ``repeat the inspections . . . until the terminating 
action specified in paragraph (h) of this AD is done.'' SWA noted it is 
unclear if the intent of paragraph (g) of this AD is to require 
accomplishment of the Part 1 external surface HFEC inspections of the 
skin prior to accomplishing the Part 3 preventive modification 
instructions, or if the intent of paragraph (g) of the proposed AD is 
to provide the operator the option to accomplish paragraph (h) of the 
proposed AD (preventive modification) in lieu of accomplishing 
paragraph (g) of the proposed AD (inspections), since the Part 3 
modification instructions include open hole HFEC inspections of the 
skin.
    We agree to provide clarification. Paragraph (g) of this AD is not 
required at the time of accomplishment of the preventive modification 
specified in paragraph (h) of this AD. Paragraph (h) of this AD states 
that the preventive modification (including all applicable related 
investigative and corrective actions) terminates the inspections in 
paragraph (g) of this AD. This means all inspections (initial and 
repetitive) in paragraph (g) of this AD are not required if paragraph 
(h) of this AD is done. We have not changed this AD in this regard.

Request for Clarification of Existing Repairs

    SWA requested clarification about existing repairs that meet the 
requirements of note (a) in tables 1 and 2 of paragraph l.E., 
``Compliance,'' of Boeing Alert Service Bulletin 737-53A1328, dated 
July 22, 2014. SWA also requested to extend the note to apply to 
existing repairs that address damage other than cracking, provided that 
the repairs are evaluated and approved by Boeing via an FAA Form 8100-
9. In addition, SWA requested we clarify whether note (a) applies only 
to reinforcing repairs that encompass all twelve fastener locations at 
a window corner, or if note (a) also applies to existing non-
reinforcing oversize hole repairs.
    We partially agree with the commenter. We agree with adding a 
paragraph to this AD to provide credit for previously approved repairs 
to address cracking issues, because Boeing Organization Designation 
Authorization (ODA) approved repairs installed prior the effective date 
of this AD are acceptable for terminating the initial and repetitive 
inspections in the area under the repair. We disagree with allowing any 
other repair as an alternative method of compliance (AMOC) because 
other repairs may or may not address the cracking issue. However, 
operators may request approval of an AMOC for these repairs using the 
procedures specified in paragraph (l) of this AD.
    We have added new paragraph (g)(1) to this AD to specify that the 
inspections required by the introductory text of paragraph (g) of this 
AD may be terminated in areas with repairs installed prior to the 
effective date of this AD, provided the repairs are reinforcing and 
address the cracking issue addressed in this AD, and installation was 
approved by the Boeing Commercial Airplanes ODA via FAA Form 8100-9.

Request for Clarification of the Termination of Inspection for Repaired 
Area for Group 1 Airplanes

    All Nippon Airways (ANA) requested we clarify if, for Group 1 
airplanes as identified in paragraph 1.A.1 ``Effectivity,'' of Boeing 
Alert Service Bulletin 737-53A1328, dated July 22, 2014, areas repaired 
using Boeing Alert Service Bulletin 737-53A1328, dated July 22, 2014, 
is terminating action for the repaired area. ANA pointed out that table 
1 of Boeing Alert Service Bulletin 737-53A1328, dated July 22, 2014, 
includes this wording.
    We agree to provide clarification. Accomplishing a repair in 
accordance with Part 6 of the Accomplishment Instructions of Boeing 
Alert Service Bulletin 737-53A1328, dated July 22, 2014, also 
terminates the inspection of the repaired area for Group 1 airplanes. 
We have added new paragraph (g)(2) to this AD to specify that repairs 
done in accordance with Part 6 of the Accomplishment Instructions of 
Boeing Alert Service Bulletin 737-53A1328, dated July 22, 2014, 
terminate the inspection required by paragraph (g) of this AD in only 
the repaired area for Group 1 airplanes only.

Request To Include Provisions for Airplanes Previously Inspected, 
Modified, and/or Repaired

    SWA requested that we revise the NPRM to include provisions for 
airplanes that were previously inspected, modified, and/or repaired 
using step 3 of the Accomplishment Instructions of Boeing Service 
Bulletin 737-53-1306, dated September 22, 2010; Revision 1, dated March 
17, 2010; Revision 2, dated October 25, 2011; or Revision 3, dated 
January 22, 2014; as terminating action for the inspections required by 
paragraph (g) of the proposed AD, as well as any documented deviations 
that were approved by the Boeing ODA via an FAA Form 8100-9.
    SWA stated that step 3 of Boeing Service Bulletin 737-53-1306 (all 
revisions) includes inspection, preventive modification, and repair 
instructions for the window corner locations addressed by the proposed 
AD. Figures 8 through 10 of Boeing Service Bulletin 737-53-1306 (all 
revisions) provide inspection and preventive modification instructions, 
which also include instructions for a fastener oversize repair, edge 
margin requirements, and window forging replacement. Figures 13 through 
18 provide external reinforcing repair instructions. Figures 40 through 
43 were added in Boeing Service Bulletin 737-53-1306, Revision 3, dated 
January 22, 2014, to incorporate the option to replace the window belt 
panels in lieu of accomplishing the window corner inspections, 
preventive modification, and approved repairs. SWA stated that it 
considers the instructions in Step 3 of Boeing Service Bulletin 737-53-
1306 (all revisions) to meet the intent of the proposed AD since the 
instructions address and eliminate the unsafe condition that prompted 
the proposed AD.
    We do not agree to revise this AD because Boeing Service Bulletin 
737-53-1306 is specific for SWA. We do not consider it appropriate to 
include various provisions in an AD applicable only to a single 
operator's unique configuration of affected airplanes. However, SWA may 
submit a request for an approval of an AMOC using the procedures 
specified in paragraph (l) of this AD. We have not changed this AD in 
this regard.

Requests To Clarify Required Actions

    SWA and ANA requested that we clarify which actions specified in 
Boeing Alert Service Bulletin 737-

[[Page 14713]]

53A1328, dated July 22, 2014, are required. SWA stated that paragraph 
(j)(3) of the proposed AD (paragraph (l)(3) in this AD) indicates that 
steps identified as ``RC'' (Required for Compliance) in Boeing Alert 
Service Bulletin 737-53A1328, dated July 22, 2014, must be accomplished 
``in order to comply with this AD.''
    The commenters noted that there are ``RC'' steps in Boeing Alert 
Service Bulletin 737-53A1328, dated July 22, 2014, that are not clearly 
addressed in the proposed AD. SWA noted that Parts 7 and 8 of Boeing 
Alert Service Bulletin 737-53A1328, dated July 22, 2014, contain steps 
that are identified as ``RC;'' however, the proposed AD does not 
mention the compliance times for these actions. SWA stated that Part 7 
of Boeing Alert Service Bulletin 737-53A1328, dated July 22, 2014, 
provides window frame replacement instructions, and steps 5 and 6 in 
Part 8 of Boeing Alert Service Bulletin 737-53A1328, dated July 22, 
2014, provide post-repair/post-modification inspection instructions for 
window frames with short edge margin conditions at the compliance times 
specified in tables 3, 4, and 8 of Boeing Alert Service Bulletin 737-
53A1328, dated July 22, 2014. SWA assumed that actions identified in 
Table 3 and Table 8 are not required for compliance and that the 
actions identified in Table 4 are required for compliance. SWA also 
pointed out that step 10 of Part 2 of Boeing Alert Service Bulletin 
737-53A1328, dated July 22, 2014, is not ``RC,'' but could result in 
accomplishment of Part 7 of Boeing Alert Service Bulletin 737-53A1328, 
dated July 22, 2014, which has ``RC'' steps.
    We agree to clarify the actions required by this AD. The post-
modification and post-repair inspections identified in Table 4 and 
Table 5 in paragraph 1.E., ``Compliance,'' of Boeing Alert Service 
Bulletin 737-53A1328, dated July 22, 2014, are required by this AD. The 
accomplishment instructions of Boeing Alert Service Bulletin 737-
53A1328, dated July 22, 2014, are unclear. Therefore, we have added new 
paragraph (i) to this AD to specify the actions identified in Table 4 
and Table 5 in paragraph 1.E., ``Compliance,'' of Boeing Alert Service 
Bulletin 737-53A1328, dated July 22, 2014. We have redesignated 
subsequent paragraphs accordingly.
    Regarding Part 7 of Boeing Alert Service Bulletin 737-53A1328, 
dated July 22, 2014, if operators chose to do the modification, certain 
actions specified in Part 3, Part 4, and Part 5 of Boeing Alert Service 
Bulletin 737-53A1328, dated July 22, 2014, are identified as ``RC'' 
steps. Within those steps, there is an on-condition action, which 
specifies to do Part 7; thus, step 1 of Part 7 of Boeing Alert Service 
Bulletin 737-53A1328, dated July 22, 2014 is required for compliance.
    Steps 2, 3, and 4 of Part 8 of Boeing Alert Service Bulletin 737-
53A1328, dated July 22, 2014, are referenced in Table 3 and Table 8 in 
paragraph 1.E., ``Compliance,'' of Boeing Alert Service Bulletin 737-
53A1328, dated July 22, 2014, and are not required by this AD. We have 
added new paragraph (k) of this AD to clarify that the post-
modification inspections specified in Table 3 and Table 8 in paragraph 
1.E., ``Compliance,'' of Boeing Alert Service Bulletin 737-53A1328, 
dated July 22, 2014, are airworthiness limitations that are required by 
maintenance and operational rules; therefore, these inspections are not 
required by this AD. We have redesignated subsequent paragraphs 
accordingly.

Request To Clarify Office Responsible for AMOCs

    ANA requested that we clarify the office responsible for AMOCs. ANA 
stated that paragraph (j) of the proposed AD specifies that the Seattle 
ACO has the authority to approve AMOCs. However, ANA noted it has seen 
other ADs for out of production airplanes that refer to the Los Angeles 
ACO.
    We agree to clarify. The Los Angeles ACO is currently responsible 
for AMOCs for the airplanes identified in this AD. We have revised 
paragraphs (l)(1) and (l)(4) of this AD (paragraphs (j)(1) and (j)(4) 
of the proposed AD) to refer to the Los Angeles ACO.

Requests for Clarification of Incorrect References

    Boeing and SWA requested that we clarify incorrect references in 
Boeing Alert Service Bulletin 737-53A1328, dated July 22, 2014. The 
commenters stated that note (e) in Figure 5 of Boeing Alert Service 
Bulletin 737-53A1328, dated July 22, 2014, incorrectly references table 
2 of paragraph 3.B., Work Instructions, for post repair/modification 
inspections of short edge margins on window frames. The commenters 
stated that these references should be to table 3 of paragraph 3.B., 
Work Instructions. Boeing also identified the notes in figures 9, 10, 
11, and 12 as additional locations where the reference to table 2 
should be to table 3. The commenters requested that we clarify in this 
AD that repeat post repair and modification inspections for window 
frames with short edge margins are defined in table 3 rather than table 
2 of paragraph 3.B, Work Instructions, in Boeing Alert Service Bulletin 
737-53A1328, dated July 22, 2014.
    We agree with the commenters that the identified table references 
in Boeing Alert Service Bulletin 737-53A1328, dated July 22, 2014, are 
incorrect. We have added new paragraphs (j)(3) and (j)(4) to this AD to 
specify the correct table references. We have also added new paragraph 
(j)(5) to this AD to clarify that operators must comply with the edge 
margin requirements in Table 3 of the Accomplishment Instructions of 
Boeing Alert Service Bulletin 737-53A1328, dated July 22, 2014. We have 
also revised paragraphs (g) and (h) of this AD to include references to 
paragraphs (j)(3), (j)(4), and (j)(5) of this AD.

Effect of Winglets on Accomplishment of the Proposed Actions

    Aviation Partners Boeing stated that accomplishing Supplemental 
Type Certificate (STC) ST01219SE (http://rgl.faa.gov/
Regulatory_and_Guidance_Library/rgstc.nsf/0/
be866b732f6cf31086257b9700692796/$FILE/ST01219SE.pdf) does not affect 
the actions specified in the NPRM.
    We concur with the commenter. We have redesignated paragraph (c) of 
the proposed AD as paragraph (c)(1) of this AD and added new paragraph 
(c)(2) to this AD to state that installation of STC ST01219SE does not 
affect the ability to accomplish the actions required by this AD. 
Therefore, for airplanes on which STC ST01219SE is installed, a 
``change in product'' AMOC approval request is not necessary to comply 
with the requirements of 14 CFR 39.17.

Conclusion

    We reviewed the relevant data, considered the comments received, 
and determined that air safety and the public interest require adopting 
this 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 for correcting the unsafe condition; and
     Do not add any additional burden upon the public than was 
already proposed in the NPRM.
    We also determined that these changes will not increase the 
economic burden on any operator or increase the scope of this AD.

Related Service Information Under 1 CFR Part 51

    We reviewed Boeing Alert Service Bulletin 737-53A1328, dated July 
22, 2014. The service information describes procedures for HFEC 
inspections for

[[Page 14714]]

fatigue cracking in certain fastener locations in the window corners of 
the window belt area, and related investigative and corrective actions. 
This service information is reasonably available because the interested 
parties have access to it through their normal course of business or by 
the means identified in the ADDRESSES section.

Costs of Compliance

    We estimate that this AD affects 142 airplanes of U.S. registry.
    We estimate the following costs to comply with this AD:

                                        Estimated Costs: Required Actions
----------------------------------------------------------------------------------------------------------------
                                                                                                Cost on U.S.
           Action                  Labor cost         Parts cost       Cost per product          operators
----------------------------------------------------------------------------------------------------------------
Inspection.................  Up to 2,312 work-                  $0  Up to $196,520 per     Up to $27,905,840 per
                              hours x $85 per hour                   inspection cycle.      inspection cycle.
                              = $196,520 per
                              inspection cycle.
----------------------------------------------------------------------------------------------------------------

                                        Estimated Costs: Required Actions
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                    Action                                 Labor cost               Parts cost        product
----------------------------------------------------------------------------------------------------------------
Preventive modification.......................  108 work-hours x $85 per hour =               $0          $9,180
                                                 $9,180.
----------------------------------------------------------------------------------------------------------------

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

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
           Action                    Labor cost          Parts cost                 Cost per product
----------------------------------------------------------------------------------------------------------------
Repair......................  Up to 18 work-hours x                $0  Up to $1,530 per repair.
                               $85 per hour = $1,530
                               per repair.
----------------------------------------------------------------------------------------------------------------

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),
    (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 adding the following new airworthiness 
directive (AD):

2016-06-04 The Boeing Company: Amendment 39-18435 ; Docket No. FAA-
2015-0495; Directorate Identifier 2014-NM-172-AD.

(a) Effective Date

    This AD is effective April 22, 2016.

(b) Affected ADs

    None.

(c) Applicability

    (1) This AD applies to The Boeing Company Model 737-300, -400, 
and -500 series airplanes, certificated in any category, as 
identified in Boeing Alert Service Bulletin 737-53A1328, dated July 
22, 2014.
    (2) Installation of Supplemental Type Certificate (STC) 
ST01219SE (http://rgl.faa.gov/Regulatory_and_Guidance_Library/
rgstc.nsf/0/be866b732f6cf31086257b9700692796/$FILE/ST01219SE.pdf) 
does not affect the ability to accomplish the actions required by 
this AD. Therefore, for airplanes on which STC ST01219SE is 
installed, a ''change in product'' alternative method of compliance 
(AMOC) approval request is not necessary to comply with the 
requirements of 14 CFR 39.17.

(d) Subject

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

(e) Unsafe Condition

    This AD was prompted by reports of fatigue cracking at certain 
fastener locations in the window corners of the window belt area. We 
are issuing this AD to detect and correct fatigue cracking around 
the fastener

[[Page 14715]]

locations that could cause multiple window corner skin cracks, which 
could result in rapid decompression and loss of structural integrity 
of the airplane.

(f) Compliance

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

(g) Inspections

    At the applicable time specified in tables 1 and 2 of paragraph 
1.E., ``Compliance,'' of Boeing Alert Service Bulletin 737-53A1328, 
dated July 22, 2014, except as required by paragraph (j)(1) of this 
AD: Do external surface high frequency eddy current (HFEC) 
inspections for cracking of the skin at the 12 fastener locations at 
the upper forward and lower aft corners of each window between 
station (STA) 360 and STA 540 and at the upper aft and lower forward 
corners of each window between STA 727 and STA 908, left-side and 
right-side of the fuselage, at and between stringers S-11 and S-13; 
and all applicable related investigative and corrective actions; in 
accordance with the Accomplishment Instructions of Boeing Alert 
Service Bulletin 737-53A1328, dated July 22, 2014, except as 
required by paragraphs (j)(2), (j)(3), (j)(4), and (j)(5) of this 
AD. Do all applicable related investigative and corrective actions 
before further flight. Repeat the inspections at the applicable 
times specified in tables 1 and 2 of paragraph 1.E., ``Compliance,'' 
of Boeing Alert Service Bulletin 737-53A1328, dated July 22, 2014. 
Accomplishing the preventive modification specified in paragraph (h) 
of this AD terminates the repetitive inspections required by this 
paragraph at the modified location only.
    (1) The inspections required by the introductory text of 
paragraph (g) of this AD may be terminated in areas with repairs 
installed prior to the effective date of this AD, provided the 
repairs are reinforcing and address the cracking issue identified in 
this AD, and installation was approved by the Boeing Commercial 
Airplanes Organization Designation Authorization (ODA) via FAA Form 
8100-9.
    (2) For Group 1 airplanes identified in Boeing Alert Service 
Bulletin 737-53A1328, dated July 22, 2014: Window corner crack 
repairs terminate the inspection required by the introductory text 
of paragraph (g) of this AD in the repaired area only. The repair, 
including all applicable related investigative and corrective 
actions, must be done in accordance with Part 6 of the 
Accomplishment Instructions of Boeing Alert Service Bulletin 737-
53A1328, dated July 22, 2014, except as required by paragraphs 
(j)(2), (j)(3), (j)(4), and (j)(5) of this AD.

(h) Preventive Modification

    Accomplishment of a preventive modification in the fastener 
locations in the window corners of the window belt area between STA 
360 and STA 540 and between STA 727 and STA 908, left-side and 
right-side of the fuselage, at and between stringers S-11 and S-13, 
terminates the inspections required by paragraph (g) of this AD at 
the modified location only. The modification, including all 
applicable related investigative and corrective actions, must be 
done in accordance with Part 3 of the Accomplishment Instructions of 
Boeing Alert Service Bulletin 737-53A1328, dated July 22, 2014, 
except as required by paragraphs (j)(2), (j)(3), (j)(4), and (j)(5) 
of this AD.

(i) Repetitive Inspections, Replacements, and Corrective Actions

    For airplanes having any condition identified in Table 4 or 
Table 5 of paragraph l.E., ``Compliance,'' of Boeing Alert Service 
Bulletin 737-53A1328, dated July 22, 2014: At the applicable times 
specified in Table 4 and Table 5 of paragraph l.E., ``Compliance,'' 
of Boeing Alert Service Bulletin 737-53A1328, dated July 22, 2014, 
do a window frame replacement or an internal detailed inspection for 
cracks of the window forging around the fastener collars, as 
applicable, and do all applicable corrective actions, in accordance 
with the Accomplishment Instructions of Boeing Alert Service 
Bulletin 737-53A1328, dated July 22, 2014, except as required by 
paragraphs (j)(2), (j)(3), (j)(4), and (j)(5) of this AD. Repeat the 
inspections at the applicable times specified in table 4 and table 5 
of paragraph 1.E., ``Compliance,'' of Boeing Alert Service Bulletin 
737-53A1328, dated July 22, 2014.

(j) Exceptions to the Service Information Specifications

    (1) Where Boeing Alert Service Bulletin 737-53A1328, dated July 
22, 2014, specifies a compliance time ``after the original issue 
date of this service bulletin,'' this AD requires compliance within 
the specified compliance time after the effective date of this AD.
    (2) Where Boeing Alert Service Bulletin 737-53A1328, dated July 
22, 2014, specifies to contact Boeing for repair instructions: 
Before further flight, repair the cracking using a method approved 
in accordance with the procedures specified in paragraph (l) of this 
AD. Although Boeing Alert Service Bulletin 737-53A1328, dated July 
22, 2014, specifies to contact Boeing for repair instructions, and 
specifies that action as Required for Compliance (RC), this AD 
requires repair as specified in this paragraph.
    (3) Where note (e) of Figure 5 of Boeing Alert Service Bulletin 
737-53A1328, dated July 22, 2014, specifies to ``Refer to Paragraph 
3.B., Work Instructions, Table 2 for edge margin requirements,'' 
operators must comply with Table 3 of paragraph 3.B., ``Work 
Instructions,'' of Boeing Alert Service Bulletin 737-53A1328, dated 
July 22, 2014, for edge margin requirements.
    (4) Where the notes for fastener codes A and B in figures 9, 10, 
11, and 12 of Boeing Alert Service Bulletin 737-53A1328, dated July 
22, 2014, refer to ``Paragraph 3.B., Work Instructions, Table 2'' 
for edge margin requirements, operators must comply with Table 3 of 
paragraph 3.B., ``Work Instructions,'' of Boeing Alert Service 
Bulletin 737-53A1328, dated July 22, 2014, for edge margin 
requirements.
    (5) Where note (e) of figures 6, 7, and 8 and step 1.a.(1) of 
Part 5 of the Accomplishment Instructions of Boeing Alert Service 
Bulletin 737-53A1328, dated July 22, 2014, specifies to ``Refer to 
Paragraph 3.B., Work Instructions, Table 3 for edge margin 
requirements,'' operators must comply with Table 3 of paragraph 
3.B., ``Work Instructions,'' of Boeing Alert Service Bulletin 737-
53A1328, dated July 22, 2014, for edge margin requirements.

(k) Post-Repair Inspections/Post-Modification Inspections

    Table 3 and Table 8 of paragraph 1.E., ``Compliance,'' of Boeing 
Alert Service Bulletin 737-53A1328, dated July 22, 2014, specify 
post-modification airworthiness limitation inspections in compliance 
to 14 CFR 25.571(a)(3) at the modified locations, which support 
compliance with 14 CFR 121.1109(c)(2) or 129.109(b)(2). As 
airworthiness limitations, these inspections are required by 
maintenance and operational rules. It is therefore unnecessary to 
mandate them in this AD. Deviations from these inspections require 
FAA approval, but do not require an alternative method of 
compliance.

(l) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Los Angeles Aircraft Certification Office 
(ACO), FAA, has the authority to approve AMOCs for this AD, if 
requested using the procedures found in 14 CFR 39.19. In accordance 
with 14 CFR 39.19, send your request to your principal inspector or 
local Flight Standards District Office, as appropriate. If sending 
information directly to the manager of the ACO, send it to the 
attention of the person identified in paragraph (m) of this AD. 
Information may be emailed to: 9-ANM-LAACO-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) Except as required by paragraph (j)(2) of this AD: For 
service information that contains steps that are labeled as RC, the 
provisions of paragraphs (l)(3)(i) and (l)(3)(ii) of this AD apply.
    (i) The steps labeled as RC, including substeps under an RC step 
and any figures identified in an RC step, must be done to comply 
with this AD. An AMOC is required for any deviations to RC steps, 
including substeps and identified figures.
    (ii) Steps not labeled as RC may be deviated from using accepted 
methods in accordance with the operator's maintenance or inspection 
program without obtaining approval of an AMOC, provided the RC 
steps, including substeps and identified figures, can still be done 
as specified, and the airplane can be put back in an airworthy 
condition.
    (4) An AMOC that provides an acceptable level of safety may be 
used for any repair, modification, or alteration required by this AD 
if it is approved by the Boeing Commercial Airplanes ODA that has 
been authorized by the Manager, Los Angeles ACO, to make those 
findings. To be approved, the repair method, modification deviation, 
or alteration deviation must meet the certification basis of the 
airplane, and the approval must specifically refer to this AD.

[[Page 14716]]

(m) Related Information

    For more information about this AD, contact Jennifer 
Tsakoumakis, Aerospace Engineer, Airframe Branch, ANM-120L, FAA, Los 
Angeles Aircraft Certification Office (ACO), 3960 Paramount Blvd., 
Lakewood, CA 90712-4137; phone: 562-627-5264; fax: 562-627-5210; 
email: jennifer.tsakoumakis@faa.gov.

(n) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do 
the actions required by this AD, unless the AD specifies otherwise.
    (i) Boeing Alert Service Bulletin 737-53A1328, dated July 22, 
2014.
    (ii) Reserved.
    (3) For service information identified in this AD, contact 
Boeing Commercial Airplanes, Attention: Data & Services Management, 
P.O. Box 3707, MC 2H-65, Seattle, WA 98124-2207; telephone 206-544-
5000, extension 1; fax 206-766-5680; Internet https://www.myboeingfleet.com.
    (4) You may view this service information at the FAA, Transport 
Airplane Directorate, 1601 Lind Avenue SW., Renton, WA. For 
information on the availability of this material at the FAA, call 
425-227-1221.
    (5) You may view this 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 March 7, 2016.
Michael Kaszycki,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2016-05842 Filed 3-17-16; 8:45 am]
 BILLING CODE 4910-13-P