[Federal Register Volume 81, Number 93 (Friday, May 13, 2016)]
[Proposed Rules]
[Pages 29802-29807]
[FR Doc No: 2016-11170]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2016-6667; Directorate Identifier 2015-NM-125-AD]
RIN 2120-AA64

Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to supersede Airworthiness Directive (AD) 2009-21-
01, which applies to certain Boeing Model 737-300 and 737-400 series
airplanes. AD 2009-21-01 currently requires repetitive inspections to
detect cracking of the aft fuselage skin, and related investigative and
corrective actions if necessary. Since we issued AD 2009-21-01, an
evaluation by the design approval holder (DAH) indicates that the aft
fuselage skin is subject to widespread fatigue damage (WFD). This
proposed AD would add new aft fuselage skin inspections for cracking,
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. The proposed AD also removes Model 737-400 series
airplanes from the applicability. We are proposing 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 and reduced structural integrity of the airplane.

DATES: We must receive comments on this proposed AD by June 27, 2016.

ADDRESSES: You may send comments, using the procedures found in 14 CFR
11.43 and 11.45, by any of the following methods:
     Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
     Fax:<PHONE_NUMBER>.
     Mail: U.S. Department of Transportation, Docket
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New
Jersey Avenue SE., Washington, DC 20590.
     Hand Delivery: Deliver to Mail address above between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    For service information identified in this NPRM, contact Boeing
Commercial Airplanes, Attention: Data & Services Management, P.O. Box
3707, MC 2H-65, Seattle, WA 98124-2207; telephone:<PHONE_NUMBER>,
extension 1; fax:<PHONE_NUMBER>; 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<PHONE_NUMBER>. It is also available on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2016-
6667.

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-2016-
6667; 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 proposed AD, the regulatory evaluation, any comments
received, and other information. The street address for the Docket
Office (phone:<PHONE_NUMBER>) is in the ADDRESSES section. Comments will
be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT: Wade Sullivan, Aerospace Engineer,
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office
(ACO), 1601 Lind Avenue SW., Renton, WA 98057-3356; phone: 425-917-
6430; fax:<PHONE_NUMBER>; email<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to send any written relevant data, views, or
arguments about this proposed AD. Send your comments to an address
listed under the ADDRESSES section. Include ``Docket No. FAA-2016-6667;
Directorate Identifier 2015-NM-125-AD'' at the beginning of your
comments. We specifically invite comments on the overall regulatory,
economic, environmental, and energy aspects of this proposed AD. We
will consider all comments received by the closing date and may amend
this proposed AD because of those comments.
    We will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We
will also post a report summarizing each substantive verbal contact we
receive about this proposed AD.

Discussion

    Fatigue damage can occur locally, in small areas or structural
design details, or globally, in widespread areas. Multiple-site damage
is widespread damage that occurs in a large structural element such as
a single rivet line of a lap splice joining two large skin panels.
Widespread damage can also occur in multiple elements such as adjacent
frames or stringers. Multiple-site damage and multiple-element damage
cracks are typically too small initially to be reliably detected with
normal inspection methods. Without intervention, these cracks will
grow, and eventually compromise the structural integrity of the
airplane. This condition is known as widespread fatigue damage. It is
associated with general degradation of large areas of structure with
similar structural details and stress levels. As an airplane ages, WFD
will likely occur, and will certainly occur if the airplane is operated
long enough without any intervention.
    The FAA's WFD final rule (75 FR 69746, November 15, 2010) became
effective on January 14, 2011. The WFD rule requires certain actions to
prevent structural failure due to WFD throughout the operational life
of certain existing transport category airplanes and all of these
airplanes that will be certificated in the future. For existing and
future airplanes subject to the WFD rule, the rule requires that DAHs
establish a limit of validity (LOV) of the engineering data that
support the structural maintenance program. Operators affected by the
WFD rule may not fly an airplane beyond its LOV, unless an extended LOV
is approved.
    The WFD rule (75 FR 69746, November 15, 2010) does not require
identifying and developing maintenance actions if the DAHs can show
that such actions are not necessary to prevent WFD before the airplane
reaches the LOV. Many LOVs, however, do depend on accomplishment of
future maintenance actions. As stated in the WFD rule, any maintenance
actions necessary to reach the LOV will be mandated by airworthiness
directives through separate rulemaking actions.
    In the context of WFD, this action is necessary to enable DAHs to
propose LOVs that allow operators the longest operational lives for
their airplanes, and still ensure that WFD will not occur. This
approach allows for an implementation strategy that provides
flexibility to DAHs in determining the timing of service information
development (with FAA approval), while providing operators with
certainty regarding the LOV applicable to their airplanes.
    On September 25, 2009, we issued AD 2009-21-01, Amendment 39-16038
(74 FR 52395, October 13, 2009) (``AD 2009-21-01''), for certain Boeing
Model 737-300 and 737-400 series airplanes. AD 2009-21-01 requires
repetitive inspections to detect cracking of the aft fuselage skin, and
related investigative and corrective actions if necessary. AD 2009-21-
01 resulted from reports of cracks in the aft fuselage skin on both
sides of the airplane. We issued AD 2009-21-01 to detect and correct
cracking in the aft fuselage skin along the longitudinal edges of the
bonded skin doubler, which could result in reduced structural integrity
of the airplane.

Actions Since AD 2009-21-01 Was Issued

    Since we issued AD 2009-21-01, additional cracks have been found on
airplanes in the skin panels from station 727 to station 1016 and from
stringer S-14 to stringer S-25 on the left and right sides of the
airplanes. Cracks at fastener holes in the bonded doubler have also
been reported on several airplanes in the area above stringer S-17 on
the left and right side of the airplanes.
    An evaluation by the DAH indicates that the aft fuselage skin is
subject to WFD. On the existing skin panel assemblies, the doubler is
chemically milled to create pockets of various depths. At these skin
panel locations on the airplane, the loads could cause a condition
where cracks could form along the longitudinal edges of the doubler.
    AD 2009-21-01 applies to certain Boeing Model 737-300 and 737-400
series airplanes. This proposed AD is applicable to certain Model 737-
300 series airplanes. We are considering issuing additional rulemaking
that will apply to Model 737-400 series airplanes. We have determined
that, in

this case, a less burdensome approach is to issue separate ADs
applicable only to each model type.

Related Service Information Under 1 CFR Part 51

    We reviewed Boeing Special Attention Service Bulletin 737-53-1168,
Revision 4, dated June 3, 2015. 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.

FAA's Determination

    We are proposing this AD because we evaluated all the relevant
information and determined the unsafe condition described previously is
likely to exist or develop in other products of the same type design.

Proposed AD Requirements

    Although this proposed AD does not explicitly restate the
requirements of AD 2009-21-01, this proposed AD would retain all of the
requirements of AD 2009-21-01 for Model 737-300 series airplanes,
except the skin panel replacement is terminating action only if the
skin panel replacement is done with a production skin panel after
53,000 total flight cycles. Those requirements are referenced in the
service information identified previously, which, in turn, is
referenced in paragraphs (g) and (h) of this proposed AD. This proposed
AD would require accomplishing the actions specified in the service
information described previously, except as discussed under
``Differences Between this Proposed AD and the Service Information.''
For information on the procedures and compliance times, see this
service information at http://www.regulations.gov by searching for and
locating Docket No. FAA-2016-6667.
    The phrase ``related investigative actions'' is used in this
proposed AD. ``Related investigative actions'' are follow-on actions
that (1) are related to the primary action, and (2) further investigate
the nature of any condition found. Related investigative actions in an
AD could include, for example, inspections.
    The phrase ``corrective actions'' is used in this proposed AD.
``Corrective actions'' are actions that correct or address any
condition found. Corrective actions in an AD could include, for
example, repairs.

Differences Between This Proposed AD and the Service Information

    Boeing Special Attention Service Bulletin 737-53-1168, Revision 4,
dated June 3, 2015, specifies to contact the manufacturer for
instructions on how to repair certain conditions and also to obtain
certain work instructions, but this proposed AD would require repairing
those conditions and also to obtain those work instructions in one of
the following ways:
     In accordance with a method that we approve; or
     Using data that meet the certification basis of the
airplane, and that have been approved by the Boeing Commercial
Airplanes Organization Designation Authorization (ODA) whom we have
authorized to make those findings.
    Table 6 of paragraph 1.E., ``Compliance,'' of Boeing Special
Attention Service Bulletin 737-53-1168, Revision 4, dated June 3, 2015,
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. This
difference has been coordinated with Boeing.

Explanation of Compliance Time

    The compliance time for the modification specified in this proposed
AD for addressing WFD was established to ensure that discrepant
structure is modified before WFD develops in airplanes. Standard
inspection techniques cannot be relied on to detect WFD before it
becomes a hazard to flight. We will not grant any extensions of the
compliance time to complete any AD-mandated service bulletin related to
WFD without extensive new data that would substantiate and clearly
warrant such an extension.

Costs of Compliance

    We estimate that this proposed AD affects 168 airplanes of U.S.
registry.
    We estimate the following costs to comply with this proposed AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
          Action                  Labor cost         Parts cost  Cost per product      Cost on U.S. operators
----------------------------------------------------------------------------------------------------------------
Inspections...............  Up to 1,791                      $0  Up to $152,235..  Up to $25,575,480.
                             work[dash]hours x $85
                             per hour = $152,235.
Skin replacement..........  624 work-hours x $85        $98,275  $151,315........  $25,420,920.
                             per hour = $53,040.
----------------------------------------------------------------------------------------------------------------

    We estimate the following costs to do any necessary repairs that
would be required based on the results of the proposed 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 hour =             [\1\]   $2,040 per repair.
                                       $2,040 per repair.
Permanent repair....................  Up to 43 work[dash]hours x $85             [\1\]   Up to $3,655 per
                                       per hour = $3,655 per repair.                      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 proposed 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

    We have determined that this proposed AD would not have federalism
implications under Executive Order 13132. This proposed AD would 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 the proposed
regulation:
    (1) Is not a ``significant regulatory action'' under Executive
Order 12866,
    (2) Is not a ``significant rule'' under the 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.

The Proposed Amendment

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

PART 39--AIRWORTHINESS DIRECTIVES

0
1. The authority citation for part 39 continues to read as follows:

    Authority:  49 U.S.C. 106(g), 40113, 44701.

Sec.  39.13  [Amended]

0
2. The FAA amends Sec.  39.13 by removing Airworthiness Directive (AD)
2009-21-01, Amendment 39-16038 (74 FR 52395, October 13, 2009), and
adding the following new AD:

The Boeing Company: Docket No. FAA-2016-6667; Directorate Identifier
2015-NM-125-AD.

(a) Comments Due Date

    The FAA must receive comments on this AD action by June 27,
2016.

(b) Affected ADs

    This AD replaces AD 2009-21-01, Amendment 39-16038 (74 FR 52395,
October 13, 2009) (``AD 2009-21-01'').

(c) Applicability

    This AD applies to Boeing Model 737-300 series airplanes,
certificated in any category, as identified in Boeing Special
Attention Service Bulletin 737-53-1168, Revision 4, dated June 3,
2015.

(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) indicates that the aft fuselage skin is subject to
widespread fatigue damage (WFD). 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 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 and 2 of paragraph
1.E., ``Compliance,'' of Boeing Special Attention Service Bulletin
737-53-1168, Revision 4, dated June 3, 2015, except as required 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 Boeing Special
Attention Service Bulletin 737-53-1168, Revision 4, dated June 3,
2015, 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 and 2 of paragraph
1.E., ``Compliance,'' of Boeing Special Attention Service Bulletin
737-53-1168, Revision 4, dated June 3, 2015. Accomplishment of a
repair in accordance with ``Part 4: Repair'' of the Accomplishment
Instructions of Boeing Special Attention Service Bulletin 737-53-
1168, Revision 4, dated June 3, 2015, 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 Boeing Special Attention Service Bulletin 737-53-
1168, Revision 4, Dated June 3, 2015

    (1) Where Boeing Special Attention Service Bulletin 737-53-1168,
Revision 4, dated June 3, 2015, specifies compliance times ``after
the Revision 4 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
Boeing Special Attention Service Bulletin 737-53-1168, Revision 4,
dated June 3, 2015, refers to airplanes in certain configurations as
of the ``issue date of Revision 4 of this service bulletin.''
However, this AD applies to airplanes in the specified
configurations ``as of the effective date of this AD.''
    (3) Where Boeing Special Attention Service Bulletin 737-53-1168,
Revision 4, dated June 3, 2015, 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 and 2 of paragraph 1.E., ``Compliance,''
Boeing Special Attention Service Bulletin 737-53-1168, Revision 4,
dated June 3, 2015, 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 737-53-1168, Revision 3, dated
November 28, 2006: At the applicable times specified in table 3 of
paragraph 1.E., ``Compliance,'' of Boeing Special Attention

Service Bulletin 737-53-1168, Revision 4, dated June 3, 2015, 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 Boeing Special
Attention Service Bulletin 737-53-1168, Revision 4, dated June 3,
2015, 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 Boeing Special Attention Service
Bulletin 737-53-1168, Revision 4, dated June 3, 2015.
    (ii) Make the time limited repair permanent; and do all
applicable related investigative and corrective actions; in
accordance with the Accomplishment Instructions of Boeing Special
Attention Service Bulletin 737-53-1168, Revision 4, dated June 3,
2015, 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 Boeing Special Attention Service Bulletin 737-53-1168,
Revision 4, dated June 3, 2015: At the applicable times specified in
table 4 of paragraph 1.E., ``Compliance,'' of Boeing Special
Attention Service Bulletin 737-53-1168, Revision 4, dated June 3,
2015: 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 related investigative and corrective actions; in
accordance with the Accomplishment Instructions of Boeing Special
Attention Service Bulletin 737-53-1168, Revision 4, dated June 3,
2015, 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 Boeing Special Attention Service Bulletin 737-53-
1168, Revision 4, dated June 3, 2015.
    (ii) Make the time limited repair permanent; and do all
applicable related investigative and corrective actions; in
accordance with the Accomplishment Instructions of Boeing Special
Attention Service Bulletin 737-53-1168, Revision 4, dated June 3,
2015, 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 737-53-1168,
Revision 3, dated November 28, 2006: At the applicable times
specified in table 5 of paragraph 1.E., ``Compliance,'' of Boeing
Special Attention Service Bulletin 737-53-1168, Revision 4, dated
June 3, 2015, except as provided by paragraphs (h)(1) of this AD:
Modify the existing permanent repair; and do all applicable related
investigative and corrective actions; in accordance with the
Accomplishment Instructions of Boeing Special Attention Service
Bulletin 737-53-1168, Revision 4, dated June 3, 2015, 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 6 of paragraph 1.E., ``Compliance,'' of Boeing Service
Bulletin Special Attention Service Bulletin 737-53-1168, Revision 4,
dated June 3, 2015, 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 Boeing Special
Attention Service Bulletin 737-53-1168, Revision 4, dated June 3,
2015. 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.
    (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 737-53-1168,
Revision 3, dated November 28, 2006, except as required by paragraph
(h)(4) of this AD. Boeing Service Bulletin 737-53-1168, Revision 3,
dated November 28, 2006, was incorporated by reference in 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 737-53-1168,
Revision 3, dated November 28, 2006, except as required by paragraph
(h)(4) of this AD; provided the skin panel replacement was done with
a production skin panel after 53,000 total flight cycles. Boeing
Service Bulletin 737-53-1168, Revision 3, dated November 28, 2006,
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 any
service information specified in paragraphs (m)(3)(i), (m)(3)(ii),
and (m)(3)(iii) of this AD, except as required by paragraph (h)(4)
of this AD; provided the skin panel replacement was done with a
production skin panel after 53,000 total flight cycles. The service
information specified in paragraphs (m)(3)(i), (m)(3)(ii), and
(m)(3)(iii) of this AD are not incorporated by reference in this AD.
    (i) Part 3 of the Accomplishment Instructions of Boeing Service
Bulletin 737-53-1168, dated March 16, 1995.
    (ii) Part 3 of the Accomplishment Instructions of Boeing Service
Bulletin 737-53-1168, Revision 1, dated August 17, 1995.
    (iii) Part 3 of the Accomplishment Instructions of Boeing
Service Bulletin 737-53-1168, Revision 2, dated November 27, 1996.

(n) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Seattle 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<EMAIL_ADDRESS>    (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, Seattle 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 previously for repairs for AD 2009-21-01 are
approved as AMOCs for the corresponding provisions of paragraph (g)
of this AD.
    (5) 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.

(o) Related Information

    (1) For more information about this AD, contact Wade Sullivan,
Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle ACO,
1601 Lind Avenue SW., Renton, WA 98057-3356; phone:<PHONE_NUMBER>;
fax:<PHONE_NUMBER>; email<EMAIL_ADDRESS>    (2) 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:<PHONE_NUMBER>; 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<PHONE_NUMBER>.

    Issued in Renton, Washington, on May 4, 2016.
Michael Kaszycki,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 2016-11170 Filed 5-12-16; 8:45 am]
 BILLING CODE 4910-13-P