AD 2017-10-07

[Federal Register Volume 82, Number 102 (Tuesday, May 30, 2017)]
[Rules and Regulations]
[Pages 24475-24479]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2017-10286]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2016-6666; Directorate Identifier 2015-NM-124-AD; 
Amendment 39-18881; AD 2017-10-07]
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 737-400 series airplanes. This AD was prompted 
by an evaluation by the design approval holder (DAH), which indicates 
that the aft fuselage skin is subject to widespread fatigue damage 
(WFD), and reports of aft fuselage skin cracking. This AD requires 
repetitive inspections to detect cracking of the aft fuselage skin, 
inspections to detect missing or loose fasteners and any disbonding or 
cracking of bonded doublers, permanent repairs of time-limited repairs, 
related investigative and corrective actions if necessary, and skin 
panel replacement. We are issuing this AD to address the unsafe 
condition on these products.

DATES: This AD is effective July 5, 2017.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of July 5, 
2017.

ADDRESSES: For service information identified in this final rule, 
contact Boeing Commercial Airplanes, Attention: Contractual & Data 
Services (C&DS), 2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 
90740-5600; telephone: 562-797-1717; Internet: <a href="https://www.myboeingfleet.com">https://www.myboeingfleet.com</a>. 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 <a href="http://www.regulations.gov">http://www.regulations.gov</a> by searching for and locating Docket No. FAA-2016-
6666.

Examining the AD Docket

    You may examine the AD docket on the Internet at <a href="http://www.regulations.gov">http://www.regulations.gov</a> by searching for and locating Docket No. FAA-2016-
6666; 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: 
<a href="/cdn-cgi/l/email-protection#f8929d9696919e9d8ad68c8b9993978d959993918bb89e9999d69f978e"><span class="__cf_email__" data-cfemail="7f151a111116191a0d510b0c1e14100a121e14160c3f191e1e51181009">[email&#160;protected]</span></a>.

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 Boeing Model 737-
400 series airplanes. The NPRM published in the Federal Register on May 
13, 2016 (81 FR 29809) (``the NPRM''). The NPRM was prompted by an 
evaluation by the DAH, which indicates that the aft fuselage skin is 
subject to WFD, and reports of aft fuselage skin cracking. The NPRM 
proposed to require repetitive inspections to detect cracking of the 
aft fuselage skin, inspections to detect missing or loose fasteners and 
any disbonding or cracking of bonded doublers, permanent repairs of 
time-limited repairs, related investigative and corrective actions if 
necessary, and skin panel replacement. We are issuing this AD to 
prevent cracking in the aft fuselage skin along the longitudinal edges 
of the bonded skin doubler, which could result in possible rapid 
decompression and reduced 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 To Specify Repair Procedures

    Boeing requested that we revise the proposed AD to address repairs 
that are

[[Page 24476]]

installed on the airplane for reasons other than chem-mill cracking. 
Boeing provided suggested language for the AD.
    We do not agree with Boeing's request. Paragraph 3.B.1 in the 
Accomplishment Instructions of Boeing Special Attention Service 
Bulletin 737-53-1187, Revision 3, dated July 10, 2015 (``SASB 737-53-
1187 R3''), which is the referenced source of service information in 
this AD, already addresses the issue raised by Boeing. SASB 737-53-1187 
R3 does not make a distinction between repairs installed for chem-mill 
cracking and repairs installed for other reasons. Therefore, repairs 
that are installed for any reason, provided they meet the service 
information criteria, are already addressed. We have not changed this 
AD in this regard.

Request To Revise Compliance Time in Paragraph (h)(4) of the Proposed 
AD

    Boeing requested that we revise the compliance time in paragraph 
(h)(4) of the proposed AD from the time specified in SASB 737-53-1187 
R3, to a time approved by the FAA through the alternative method of 
compliance (AMOC) process.
    Boeing provided examples of how replacing skin panels at certain 
compliance times would require further skin panel replacement before 
reaching the airplane limit of validity. Boeing explained that the NPRM 
proposed skin panel replacement at 60,000 total flight cycles; 
therefore, an FAA approval to adjust the compliance time from total 
flight cycles to cycles after skin panel replacement would be required.
    We partially agree with Boeing's request. Airplanes that have had a 
skin replacement with a production skin panel, as distinguished from an 
improved-design kit skin panel, prior to 53,000 total flight cycles may 
be eligible for an adjustment of the inspection threshold. Currently, 
such an adjustment of the AD compliance time is not delegated to 
Boeing's authorized representatives, and the change must be approved by 
the FAA. However, we consider the number of airplanes affected by this 
scenario to be quite small. Therefore, we have decided to approve such 
changes to the compliance times on a case-by-case basis using the 
procedures specified in paragraph (n)(1) of this AD. Although we agree 
with the comment, we have not changed this AD in this regard.

Request To Reference Part 6 of the Service Information

    Boeing requested that we revise paragraphs (i)(1)(ii), (i)(2)(ii), 
and (j) of the proposed AD by specifying doing part 6 of the service 
information. Boeing stated that specifying the service information part 
reference would make the language consistent with paragraph (g) of the 
proposed AD, which specifies the service information part reference.
    We agree with Boeing's request. These changes will increase the 
paragraphs' clarity. We have revised paragraphs (i)(1)(ii), (i)(2)(ii), 
and (j) of this AD accordingly.

Request To Revise Paragraph (l) of the Proposed AD

    Boeing requested that we revise the provision of paragraph (l) of 
the proposed AD, which would provide for terminating action if the skin 
panel was replaced with a production skin panel. Boeing indicated that 
terminating action should also apply to airplanes with the skin panel 
replacement kit (S-20 to S-25 (left and right)) specified in Boeing 
Service Bulletin 737-53-1187. Boeing stated that the skin panel 
replacement using the kit specified in Boeing Service Bulletin 737-53-
1187 does not have the lower flight cycle limit restriction of the 
production panel replacement. Boeing explained that once the kit skin 
panel is replaced, the inspections specified in SASB 737-53-1187 R3, 
are terminated.
    We agree with Boeing's request. The kit skin panels are an improved 
design compared with the original production skin panels, have 
different inspection requirements, and provide terminating action. We 
have revised paragraph (l) of this AD accordingly.

Request To Remove Flight Cycle Restriction in Paragraphs (m)(2), 
(m)(3), and (n)(5) of the Proposed AD

    Boeing requested that we revise paragraphs (m)(2), (m)(3), and 
(n)(5) of the proposed AD by removing the flight-cycle restriction for 
credit for the skin panel replacement. Boeing explained that the only 
skin panel replacement specified in the service information referenced 
in paragraphs (m)(2) and (m)(3) of the proposed AD is the skin panel 
replacement kit, which can be accomplished at any time.
    Boeing stated that it assumed that only the kit skin panel 
replacements, and not the original production skin panels, are approved 
as AMOCs for AD 2009-21-01, Amendment 39-16038 (74 FR 52395, October 
13, 2009) (``AD 2009-21-01''). Boeing asserted that, therefore, 
paragraph (n)(5) of the proposed AD should approve previous 
modifications done as optional terminating action for AD 2009-21-01 as 
AMOCs for the modification required by paragraph (l) of this AD without 
the flight-cycle restriction.
    We partially agree with Boeing's request. The kit skin panels are 
an improved design compared with the original production skin panels 
and have different inspection requirements. We have revised paragraphs 
(m)(2) and (m)(3) of this AD by removing the flight-cycle restriction.
    However, in order to address airplanes that have had production 
skin panels replaced through AMOCs for AD 2009-21-01, paragraph (n)(5) 
of this AD retains the flight-cycle restriction.
    We agree to approve AMOCs for AD 2009-21-01 that require using the 
skin panel kit specified in Boeing Service Bulletin 737-53-1187 as 
AMOCs for the modification required by paragraph (l) of this AD without 
the flight-cycle restriction. We have added paragraph (n)(6) to this 
AD, which states that AMOCs approved for previous modifications done as 
optional terminating action for AD 2009-21-01 are approved as AMOCs for 
the modification required by paragraph (l) of this AD provided the skin 
modification replacement was done using the skin panel kit specified in 
Boeing Service Bulletin 737-53-1187.

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:
    <bullet> Are consistent with the intent that was proposed in the 
NPRM for correcting the unsafe condition; and
    <bullet> 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 SASB 737-53-1187 R3. The service information describes 
procedures for doing inspections of the fuselage skin, repairs, and 
skin panel replacement. 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 84 airplanes of U.S. registry.
    We estimate the following costs to comply with this AD:

[[Page 24477]]



                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                         Cost per
            Action                  Labor cost         Parts cost        product        Cost on U.S.  operators
----------------------------------------------------------------------------------------------------------------
Inspections..................  Up to 1,568 work-                 $0  Up to $133,280.  Up to $11,195,520.
                                hours x $85 per
                                hour = Up to
                                $133,280.
Skin replacement.............  698 work-hours x $85         185,147  $244,477.......  $20,536,068.
                                per hour = $59,330.
----------------------------------------------------------------------------------------------------------------

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

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
             Action                      Labor cost           Parts cost              Cost per product
----------------------------------------------------------------------------------------------------------------
Time-limited repair.............  24 work-hours x $85 per            (\1\)  $2,040 per repair.
                                   hour = $2,040 per
                                   repair.
Permanent repair................  Up to 39 work-hours x              (\1\)  Up to $3,315 per repair.
                                   $85 per hour = $3,315
                                   per repair.
----------------------------------------------------------------------------------------------------------------
\1\ We have received no definitive data that would enable us to provide the part cost estimates for the on-
  condition actions specified in this AD.

    We estimate the following costs to do any necessary post-repair 
inspections that would be required. We have no way of determining the 
number of aircraft that might need these inspections:

                                          Post-Repair Inspection Costs
----------------------------------------------------------------------------------------------------------------
                Action                            Labor cost             Parts cost        Cost per  product
----------------------------------------------------------------------------------------------------------------
Post-repair inspection................  Up to 7 work[dash]hours x $85              $0  Up to $595.
                                         per hour = $595.
----------------------------------------------------------------------------------------------------------------

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):

2017-10-07 The Boeing Company: Amendment 39-18881; Docket No. FAA-
2016-6666; Directorate Identifier 2015-NM-124-AD.

(a) Effective Date

    This AD is effective July 5, 2017.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to Boeing Model 737-400 series airplanes, 
certificated in any category, as identified in Boeing Special 
Attention Service Bulletin 737-53-1187, Revision 3, dated July 10, 
2015 (``SASB 737-53-1187 R3'').

(d) Subject

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

(e) Unsafe Condition

    This AD was prompted by an evaluation by the design approval 
holder (DAH) which indicates that the aft fuselage skin is subject 
to widespread fatigue damage (WFD) and reports of aft fuselage skin 
cracking. We are issuing this AD to detect and correct cracking in 
the aft fuselage skin along the longitudinal edges of the bonded 
skin doubler, which could result in possible rapid decompression

[[Page 24478]]

and reduced structural integrity of the airplane.

(f) Compliance

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

(g) Inspections, Related Investigative and Corrective Actions

    At the applicable times specified in tables 1, 2, and 3 of 
paragraph 1.E., ``Compliance,'' of SASB 737-53-1187 R3, except as 
provided by paragraph (h)(1) and (h)(2) of this AD: Do the 
applicable inspections to detect cracks in the aft fuselage skin 
panels; and do all applicable related investigative and corrective 
actions; in accordance with the Accomplishment Instructions of SASB 
737-53-1187 R3, except as required by paragraphs (h)(3) and (h)(4) 
of this AD. Do all applicable related investigative and corrective 
actions before further flight. Repeat the applicable inspections 
thereafter at the applicable intervals specified in tables 1, 2, and 
3 of paragraph 1.E., ``Compliance,'' of SASB 737-53-1187 R3. 
Accomplishment of a repair in accordance with ``Part 4: Repair'' of 
the Accomplishment Instructions of SASB 737-53-1187 R3, except as 
required by paragraph (h)(3) of this AD, is terminating action for 
the repetitive inspections required by this paragraph at the 
repaired locations only.

(h) Exceptions to SASB 737-53-1187 R3

    (1) Where SASB 737-53-1187 R3, specifies compliance times 
``after the Revision 3 date of this service bulletin,'' this AD 
requires compliance within the specified compliance times after the 
effective date of this AD.
    (2) The Condition column of Paragraph 1.E., ``Compliance,'' of 
SASB 737-53-1187 R3, refers to airplanes in certain configurations 
as of the ``issue date of Revision 3 of this service bulletin.'' 
However, this AD applies to airplanes in the specified 
configurations as of the effective date of this AD.
    (3) Where SASB 737-53-1187 R3 specifies contacting Boeing for 
repair instructions or work instructions, before further flight, 
repair or perform the work instructions using a method approved in 
accordance with the procedures specified in paragraph (n) of this 
AD, except as required by paragraph (h)(4) of this AD.
    (4) For airplanes on which an operator has a record that a skin 
panel was replaced with a production skin panel before 53,000 total 
flight cycles: At the applicable time for the next inspection as 
specified in tables 1, 2, and 3 of paragraph 1.E., ``Compliance,'' 
of SASB 737-53-1187 R3, except as provided by paragraph (h)(1) and 
(h)(2) of this AD: Perform inspections and applicable corrective 
actions using a method approved in accordance with the procedures 
specified in paragraph (n) of this AD.

(i) Actions for Airplanes With a Time-Limited Repair Installed

    (1) For airplanes with a time-limited repair installed as 
specified in Boeing Service Bulletin 737-53-1187, Revision 2, dated 
May 9, 2007: At the applicable times specified in table 4 of 
paragraph 1.E., ``Compliance,'' of SASB 737-53-1187 R3, except as 
provided by paragraphs (h)(1) and (h)(2) of this AD: Do the actions 
specified in paragraphs (i)(1)(i) and (i)(1)(ii) of this AD.
    (i) Do the applicable inspections to detect missing or loose 
fasteners and any disbonding or cracking of bonded doublers; and do 
all applicable related investigative and corrective actions; in 
accordance with the Accomplishment Instructions of SASB 737-53-1187 
R3, except as required by paragraph (h)(3) of this AD. Do all 
applicable related investigative and corrective actions before 
further flight. Repeat the applicable inspections thereafter at the 
applicable intervals specified in table 4 of paragraph 1.E., 
``Compliance,'' of SASB 737-53-1187 R3.
    (ii) Make the time-limited repair permanent; and do all 
applicable related investigative and corrective actions; in 
accordance with Part 6 of the Accomplishment Instructions of SASB 
737-53-1187 R3, except as required by paragraph (h)(3) of this AD. 
Do all applicable related investigative and corrective actions 
before further flight. Accomplishing the permanent repair required 
by this paragraph terminates the inspections required by paragraph 
(i)(1)(i) of this AD for the permanently repaired area only.
    (2) For airplanes with a time-limited repair installed as 
specified in SASB 737-53-1187 R3: At the applicable times specified 
in table 5 of paragraph 1.E., ``Compliance,'' of SASB 737-53-1187 
R3, except as provided by paragraph (h)(2) of this AD: Do the 
actions specified in paragraphs (i)(2)(i) and (i)(2)(ii) of this AD.
    (i) Do the applicable inspections to detect missing or loose 
fasteners and any disbonding or cracking of bonded doublers; and do 
all applicable corrective actions; in accordance with the 
Accomplishment Instructions of SASB 737-53-1187 R3, except as 
required by paragraph (h)(3) of this AD. Do all applicable 
corrective actions before further flight. Repeat the applicable 
inspections thereafter at the applicable intervals specified in 
table 5 of paragraph 1.E., ``Compliance,'' of SASB 737-53-1187 R3.
    (ii) Make the time-limited repair permanent; and do all 
applicable related investigative and corrective actions; in 
accordance with Part 6 of the Accomplishment Instructions of SASB 
737-53-1187 R3, except as required by paragraph (h)(3) of this AD. 
Do all applicable related investigative and corrective actions 
before further flight. Accomplishing the permanent repair required 
by this paragraph terminates the inspections required by paragraph 
(i)(2)(i) of this AD for the permanently repaired area only.

(j) Modification of Certain Permanent Repairs

    For airplanes with an existing time-limited repair that was made 
permanent as specified in Boeing Service Bulletin 737-53-1187, 
Revision 2, dated May 9, 2007: At the applicable time specified in 
table 6 of paragraph 1.E., ``Compliance,'' of SASB 737-53-1187 R3, 
except as provided by paragraph (h)(1) of this AD: Modify the 
existing permanent repair; and do all applicable related 
investigative and corrective actions; in accordance with Part 6 of 
the Accomplishment Instructions of SASB 737-53-1187 R3, except as 
required by paragraph (h)(3) of this AD. Do all applicable related 
investigative and corrective actions before further flight.

(k) Post-Repair Inspections

    Table 7 of paragraph 1.E., ``Compliance,'' of SASB 737-53-1187 
R3, specifies post-repair airworthiness limitation inspections in 
compliance with 14 CFR 25.571(a)(3) at the repaired 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) Skin Panel Replacement

    At the later of the times specified in paragraphs (l)(1) and 
(1)(2) of this AD: Replace the applicable skin panels, and do all 
applicable related investigative and corrective actions, in 
accordance with the Accomplishment Instructions of SASB 737-53-1187 
R3. Do all applicable related investigative and corrective actions 
before further flight. Doing the skin panel replacement required by 
this paragraph terminates the inspection requirements of paragraphs 
(g), (i), and (j) of this AD for that skin panel only, provided the 
skin panel replacement was done with a production skin panel after 
53,000 total flight cycles, or with the skin panel replacement kit 
(S-20 to S-25 (left and right)) specified in Boeing Service Bulletin 
737-53-1187.
    (1) Before 60,000 total flight cycles, but not before 53,000 
total flight cycles.
    (2) Within 6,000 flight cycles after the effective date of this 
AD, but not before 53,000 total flight cycles.

(m) Credit for Previous Actions

    (1) This paragraph provides credit for the actions required by 
paragraph (g) of this AD, if those actions were performed before the 
effective date of this AD using Boeing Service Bulletin 737-53-1187, 
Revision 2, dated May 9, 2007, except as required by paragraph 
(h)(4) of this AD. Boeing Service Bulletin 737-53-1187, Revision 2, 
dated May 9, 2007, was incorporated by reference in AD 2009-21-01, 
Amendment 39-16038 (74 FR 52395, October 13, 2009) (``AD 2009-21-
01'').
    (2) This paragraph provides credit for the actions required by 
paragraph (l) of this AD, if those actions were performed before the 
effective date of this AD using Boeing Service Bulletin 737-53-1187, 
Revision 2, dated May 9, 2007, except as required by paragraph 
(h)(4) of this AD. Boeing Service Bulletin 737-53-1187, Revision 2, 
dated May 9, 2007, was incorporated by reference in AD 2009-21-01.
    (3) This paragraph provides credit for the actions required by 
paragraph (l) of this AD, if those actions were performed before 
November 17, 2009 (the effective date of AD 2009-21-01) using Part 
III of the Accomplishment Instructions of Boeing

[[Page 24479]]

Service Bulletin 737-53-1187, dated November 2, 1995; or Part III of 
the Accomplishment Instructions of Boeing Service Bulletin 737-53-
1187, Revision 1, dated January 16, 1997, except as required by 
paragraph (h)(4) of this AD. Boeing Service Bulletin 737-53-1187, 
dated November 2, 1995; and Boeing Service Bulletin 737-53-1187, 
Revision 1, dated January 16, 1997; are not incorporated by 
reference in this AD.

(n) 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 (o)(1) of this AD. 
Information may be emailed to: <a href="/cdn-cgi/l/email-protection#f8c1d5b9b6b5d5b4b9b9bbb7d5b9b5b7bbd5aa9d898d9d8b8c8bb89e9999d69f978e"><span class="__cf_email__" data-cfemail="d0e9fd919e9dfd9c9191939ffd919d9f93fd82b5a1a5b5a3a4a390b6b1b1feb7bfa6">[email&#160;protected]</span></a>.
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the local flight standards district office/certificate holding 
district office.
    (3) An AMOC that provides an acceptable level of safety may be 
used for any repair, modification, or alteration required by this AD 
if it is approved by the Boeing Commercial Airplanes Organization 
Designation Authorization (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.
    (4) AMOCs approved for repairs for AD 2009-21-01 are approved as 
AMOCs for the corresponding provisions of paragraph (g) of this AD.
    (5) Except as specified in paragraph (n)(6) of this AD, AMOCs 
approved for previous modifications done as optional terminating 
action for AD 2009-21-01 are approved as AMOCs for the modification 
required by paragraph (l) of this AD provided the previous 
modification was done after the airplane had accumulated 53,000 
total flight cycles or more.
    (6) AMOCs approved for previous modifications done as optional 
terminating action for AD 2009-21-01 are approved as AMOCs for the 
modification required by paragraph (l) of this AD provided the skin 
modification replacement is done using the skin panel kit specified 
Boeing Service Bulletin 737-53-1187.

(o) Related Information

    (1) For more information about this AD, contact Jennifer 
Tsakoumakis, Aerospace Engineer, Airframe Branch, ANM-120L, FAA, Los 
Angeles ACO, 3960 Paramount Boulevard, Lakewood, CA 90712-4137; 
phone: 562-627-5264; fax: 562-627-5210; email: 
<a href="/cdn-cgi/l/email-protection#214b444f4f484744530f5552404a4e544c404a4852614740400f464e57"><span class="__cf_email__" data-cfemail="573d3239393e313225792324363c38223a363c3e241731363679303821">[email&#160;protected]</span></a>.
    (2) Service information identified in this AD that is not 
incorporated by reference is available at the addresses specified in 
paragraphs (p)(3) and (p)(4) of this AD.

(p) 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 Special Attention Service Bulletin 737-53-1187, 
Revision 3, dated July 10, 2015.
    (ii) Reserved.
    (3) For Boeing service information identified in this AD, 
contact Boeing Commercial Airplanes, Attention: Contractual & Data 
Services (C&DS), 2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 
90740-5600; telephone: 562-797-1717; Internet: <a href="https://www.myboeingfleet.com">https://www.myboeingfleet.com</a>.
    (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: <a href="http://www.archives.gov/federal-register/cfr/ibr-locations.html">http://www.archives.gov/federal-register/cfr/ibr-locations.html</a>.

    Issued in Renton, Washington, on May 2, 2017.
Michael Kaszycki,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2017-10286 Filed 5-26-17; 8:45 am]
 BILLING CODE 4910-13-P