
[Federal Register Volume 82, Number 27 (Friday, February 10, 2017)]
[Rules and Regulations]
[Pages 10258-10262]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2017-01824]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2016-6670; Directorate Identifier 2016-NM-006-AD; 
Amendment 39-18789; AD 2017-02-10]
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 superseding Airworthiness Directive (AD) 2013-19-04 for 
certain The Boeing Company Model 737-600, -700, -700C, -800, and -900 
series airplanes. AD 2013-19-04 required repetitive inspections for 
cracking of the skin around the fasteners common to the ends of certain 
bulkhead chords, and related investigative actions and corrective 
actions if necessary; and

[[Page 10259]]

provided an optional terminating modification. This new AD reduces the 
inspection threshold and repetitive inspection intervals. This AD was 
prompted by a report of cracks found in the skin at fasteners of 
certain bulkhead chords. We are issuing this AD to address the unsafe 
condition on these products.

DATES: This AD is effective March 17, 2017.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of March 17, 
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 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-2016-
6670.

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-
6670; 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: Alan Pohl, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue SW., Renton, WA 98057-3356; phone: 425-917-6450; fax: 
425-917-6590; email: alan.pohl@faa.gov.

SUPPLEMENTARY INFORMATION:

Discussion

    We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR 
part 39 to supersede AD 2013-19-04, Amendment 39-17586 (78 FR 59801, 
September 30, 2013) (``AD 2013-19-04''). AD 2013-19-04 applied to 
certain The Boeing Company Model 737-600, -700, -700C, -800, and -900 
series airplanes. The NPRM published in the Federal Register on May 12, 
2016 (81 FR 29505) (``the NPRM''). The NPRM was prompted by a report of 
cracks found in the skin at body station (STA) 540 just below stringer 
S-22L. The NPRM proposed to continue to require repetitive detailed and 
high frequency eddy current inspections for cracking of the skin around 
the eight fasteners common to the ends of the STA 540 bulkhead chords 
between stringers S-22 and S-23, left and right sides; related 
investigative actions and corrective actions, if necessary; and to 
provide an optional terminating modification. The NPRM also proposed to 
reduce the inspection threshold and repetitive inspection intervals. We 
are issuing this AD to detect and correct fatigue cracking in the 
fuselage skin around the eight fasteners securing the STA 540 bulkhead 
chords, which could result in rapid decompression of the cabin.

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.

Support for the NPRM

    Boeing and United Airlines had no objections to the NPRM.

Effect of Winglets on Accomplishment of the Proposed Actions

    Aviation Partners Boeing stated that installation of winglets, as 
provided in Supplemental Type Certificate (STC) ST00830SE, does not 
affect the ability to accomplish the actions proposed in the NPRM.
    We concur with the commenter. We have redesignated paragraph (c) of 
the proposed AD as (c)(1) and added paragraph (c)(2) to this AD to 
state that installation of STC ST00830SE does not affect the ability to 
accomplish the actions required by this AD. Therefore, for airplanes on 
which STC ST00830SE 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.

Request To Clarify Access and Restoration Requirements

    All Nippon Airways requested that we clarify if the access and 
restoration instructions specified in the service information 
referenced in paragraph (k) of the proposed AD are required actions.
    We agree to clarify this issue. Access and restoration actions are 
not part of the actions required to correct the unsafe condition 
identified in this AD. Therefore, access and restoration actions were 
excluded from the required actions in AD 2013-19-04 and are excluded 
from the required actions in this AD. We have added the service 
information referenced in paragraph (k) of this AD to paragraph (i)(4) 
of this AD. Paragraph (i)(4) of this AD specifies that the access and 
restoration actions specified in the referenced service information are 
not required by this AD.

Request To Clarify Corrective Action

    Southwest Airlines (SWA) requested that we clarify the corrective 
action for drilling the new drag link assembly. SWA stated that the 
service information only provides instructions for parts constructed of 
aluminum and that the drag link assembly is made from titanium.
    We agree that clarification is necessary. Boeing has informed us 
that revised service information is forthcoming. However, since the 
revised service information is not yet available, we do not consider 
that delaying this action until after the release of the manufacturer's 
revised service bulletin is warranted. When this service information 
becomes available, and upon satisfactory review, we plan to approve it 
as a global alternative method of compliance (AMOC) to the appropriate 
requirements of this AD. The issue raised by SWA affects only the on-
condition repair instructions and not the required inspection to detect 
the identified unsafe condition. We have added paragraph (i)(5) to this 
AD to specify that repairs provided in Part 4 or Part 5 of the 
Accomplishment Instructions of Boeing Special Attention Service 
Bulletin 737-53-1294, Revision 2, dated December 9, 2015 (``SASB 737-
53-1294 R2''), must be done before further flight, using a method 
approved in accordance with the procedures specified in paragraph (l) 
of this AD. We have revised paragraphs (g) and (h) of this AD 
accordingly.

Clarification of Exception to Repetitive Intervals

    For clarity, we have changed the format of paragraph (g) of this AD 
to make it clear the exceptions apply to the entire paragraph, 
including the repetitive inspection sentence specified in paragraph (g) 
of this AD.

Clarification of Terminating Actions

    We have clarified paragraph (h) of this AD to specify that 
accomplishing the skin repair or preventive modification,

[[Page 10260]]

as specified in the applicable part of the Accomplishment Instructions 
of Boeing SASB 737-53-1294 R2, is terminating action for the side on 
which the skin repair or preventive modification is done.

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 SASB 737-53-1294 R2. The service information describes 
procedures for inspecting the skin around the eight fasteners common to 
the ends of the STA 540 bulkhead chords between stringers S-22 and S-
23, left and right sides, for cracking, repairing cracks, and 
installing a chord splice as a preventive modification. 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 903 airplanes of U.S. registry.
    We estimate the following costs to comply with this AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                 Cost on U.S.
             Action                      Labor cost          Parts cost    Cost per product        operators
----------------------------------------------------------------------------------------------------------------
Inspection (left and right        12 work-hours x $85 per            $0  $1,020 per           $921,060 per
 sides).                           hour = $1,020 per                      inspection cycle.    inspection cycle.
                                   inspection cycle.
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    We estimate the following costs to do any necessary repairs and 
inspections that will be required based on the results of the 
inspection. 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
----------------------------------------------------------------------------------------------------------------
Preventive modification (each      7 work-hours x $85 per     $894................  $1,489.
 side).                             hour = $595.
Skin repair (each side)..........  39 work-hours x $85 per    Up to $5,635........  Up to $8,950.
                                    hour = $3,315.
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    According to the manufacturer, some of the costs of this AD may be 
covered under warranty, thereby reducing the cost impact on affected 
individuals. We do not control warranty coverage for affected 
individuals. As a result, we have included all costs in our cost 
estimate.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, Section 106, describes the 
authority of the FAA Administrator. Subtitle VII, Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    We are issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701, ``General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on products identified in this 
rulemaking action.

Regulatory Findings

    We have determined that this AD will not have federalism 
implications under Executive Order 13132. This AD will not have a 
substantial direct effect on the States, on the relationship between 
the national government and the States, or on the distribution of power 
and responsibilities among the various levels of government.
    For the reasons discussed above, I certify that this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979),
    (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 removing Airworthiness Directive (AD) 
2013-19-04, Amendment 39-17586 (78 FR 59801, September 30, 2013), and 
adding the following new AD:

2017-02-10 The Boeing Company: Amendment 39-18789; Docket No. FAA-
2016-6670; Directorate Identifier 2016-NM-006-AD.

(a) Effective Date

    This AD is effective March 17, 2017.

(b) Affected ADs

    This AD replaces AD 2013-19-04, Amendment 39-17586 (78 FR 59801, 
September 30, 2013) (``AD 2013-19-04'').

[[Page 10261]]

(c) Applicability

    (1) This AD applies to The Boeing Company Model 737-600, -700, -
700C, -800, and -900 series airplanes, certificated in any category, 
as identified in Boeing Special Attention Service Bulletin 737-53-
1294, Revision 2, dated December 9, 2015 (``SASB 737-53-1294 R2'').
    (2) Installation of Supplemental Type Certificate (STC) 
ST00830SE [http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgstc.nsf/0/184DE9A71EC3FA5586257EAE00707DA6?OpenDocument&Highlight=st00830se] 
does not affect the ability to accomplish the actions required by 
this AD. Therefore, for airplanes on which STC ST00830SE 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 a report of cracks found in the skin at 
body station (STA) 540 just below the left side of stringer S-22. We 
are issuing this AD to detect and correct fatigue cracking in the 
fuselage skin around the eight fasteners securing the STA 540 
bulkhead chords, which could result in rapid decompression of the 
cabin.

(f) Compliance

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

(g) Inspection and Corrective Action

    Except as required by paragraphs (i)(1) and (i)(2) of this AD: 
At the applicable time specified in table 1 of paragraph 1.E., 
``Compliance,'' of SASB 737-53-1294 R2, do detailed and high 
frequency eddy current (HFEC) inspections for cracking of the skin 
in the area around the eight fasteners securing the STA 540 bulkhead 
chords between stringers S-22 and S-23; and do all applicable 
related investigative and corrective actions; in accordance with 
Parts 1, 2, 3, 4, and 5 of the Accomplishment Instructions of SASB 
737-53-1294 R2, except as required by paragraphs (i)(3), (i)(4), and 
(i)(5) of this AD. Do all applicable related investigative and 
corrective actions before further flight. Except as required by 
paragraph (i)(2) of this AD, repeat the detailed and HFEC 
inspections thereafter at the intervals specified in table 1 of 
paragraph 1.E., ``Compliance,'' of SASB 737-53-1294 R2, until the 
optional preventive modification specified in paragraph (h) of this 
AD is done.

(h) Skin Repair or Optional Preventive Modification

    Accomplishing the skin repair or preventive modification, 
including an HFEC inspection for cracking of the skin and STA 540 
bulkhead chords, and all applicable repairs, in accordance with 
paragraph 3.B, Part 2 or Part 4 (left side), or Part 3 or Part 5 
(right side), as applicable, of the Accomplishment Instructions of 
SASB 737-53-1294 R2, except as required by paragraphs (i)(2) and 
(i)(5) of this AD, terminates the inspection requirements of 
paragraph (g) of this AD for the side on which the skin repair or 
preventive modification is done.

(i) Exceptions to Service Bulletin Specifications

    (1) Where paragraph 1.E., ``Compliance,'' of SASB 737-53-1294 
R2, specifies a compliance time ``after the Revision 2 date of this 
service bulletin,'' this AD requires compliance within the specified 
compliance time after the effective date of this AD.
    (2) For airplanes on which Boeing Business Jet Lower Cabin 
Altitude Supplemental Type Certificate (STC) ST01697SE (http://
rgl.faa.gov/Regulatory_and_Guidance_Library/rgstc.nsf/0/
0812969a86af879b8625766400600105/$FILE/ST01697SE.pdf) (6,500 feet 
maximum cabin altitude in lieu of 8,000 feet) has been incorporated, 
the flight-cycle related compliance times for the inspection 
required by paragraph (g) of this AD are different from those 
specified in paragraph 1.E., ``Compliance,'' of SASB 737-53-1294 R2. 
All initial compliance times specified in total flight cycles or 
flight cycles must be reduced to half of those specified in SASB 
737-53-1294 R2. All repetitive interval compliance times specified 
in flight cycles must be reduced to one-quarter of those specified 
in paragraph 1.E., ``Compliance,'' of SASB 737-53-1294 R2.
    (3) If any cracking is found during any inspection required by 
this AD, and SASB 737-53-1294 R2, specifies to contact Boeing for 
appropriate action: Before further flight, repair using a method 
approved in accordance with the procedures specified in paragraph 
(l) of this AD.
    (4) The access and restoration actions identified in the 
Accomplishment Instructions of Boeing Special Attention Service 
Bulletin 737-53-1294, dated March 31, 2011; Boeing Special Attention 
Service Bulletin 737-53-1294, Revision 1, dated June 14, 2013; or 
SASB 737-53-1294 R2; are not required by this AD. Operators may 
perform those actions in accordance with accepted maintenance 
procedures.
    (5) For doing repairs specified in Part 4 or Part 5 of the 
Accomplishment Instructions of SASB 737-53-1294 R2: Before further 
flight, repair using a method approved in accordance with the 
procedures specified in paragraph (l) of this AD.

(j) Supplemental Inspections Not Required by This AD

    Table 2 of paragraph 1.E., ``Compliance,'' of SASB 737-53-1294 
R2, specifies post-modification airworthiness limitation inspections 
in compliance with 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 AMOC.

(k) Credit for Previous Actions

    This paragraph provides credit for the actions required by 
paragraphs (g) and (h) of this AD, if those actions were performed 
before the effective date of this AD using Boeing Special Attention 
Service Bulletin 737-53-1294, dated March 31, 2011, which is not 
incorporated by reference in this AD; or Boeing Special Attention 
Service Bulletin 737-53-1294, Revision 1, dated June 14, 2013, which 
was incorporated by reference in AD 2013-19-04.

(l) 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 (m)(1) of this AD. 
Information may be emailed to: 9-ANM-Seattle-ACO-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) 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 the optional preventive 
modification installed in accordance with paragraph (h) of AD 2013-
19-04, and AMOCs approved previously for repairs for AD 2013-19-04, 
are approved as AMOCs for the corresponding provisions of this AD, 
provided that such modification or repair included installation of 
the splice plate as specified in Boeing Special Attention Service 
Bulletin 737-53-1294, except as provided by paragraph (l)(5) of this 
AD.
    (5) The time-limited repair approved as specified in FAA Letter 
120S-15-140, dated June 3, 2015, is approved as an AMOC to the 
corresponding requirements of this AD.

(m) Related Information

    (1) For more information about this AD, contact Alan Pohl, 
Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft 
Certification Office, 1601 Lind Avenue SW., Renton, WA 98057-3356; 
phone: 425-917-6450; fax: 425-917-6590; email: alan.pohl@faa.gov.
    (2) Service information identified in this AD that is not 
incorporated by reference is available at the addresses specified in 
paragraphs (n)(3) and (n)(4) of this AD.

(n) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference

[[Page 10262]]

(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 737-53-1294, 
Revision 2, dated December 9, 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 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 January 18, 2017.
Michael Kaszycki,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2017-01824 Filed 2-9-17; 8:45 am]
 BILLING CODE 4910-13-P


