
[Federal Register Volume 81, Number 203 (Thursday, October 20, 2016)]
[Rules and Regulations]
[Pages 72511-72515]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-23078]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2015-6538; Directorate Identifier 2015-NM-031-AD; 
Amendment 39-18668; AD 2016-20-02]
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 an evaluation by the design approval holder (DAH) 
indicating that the aft pressure bulkhead is subject to widespread 
fatigue damage (WFD). This AD requires repetitive inspections of the 
aft pressure bulkhead web for any cracking, incorrectly drilled 
fastener holes, and elongated fastener holes; and related investigative 
and corrective actions, if necessary. We are issuing this AD to detect 
and correct fatigue cracking of the aft pressure bulkhead web at the 
``Y''-chord, which could result in reduced structural

[[Page 72512]]

integrity of the airplane and rapid decompression of the fuselage.

DATES: This AD is effective November 25, 2016.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of November 25, 
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-
6538.

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-
6538; 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: Payman Soltani, Aerospace Engineer, 
Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification 
Office, 3960 Paramount Boulevard, Lakewood, CA 90712-4137; telephone: 
562-627-5313; fax: 562-627-5210; email: payman.soltani@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 737-100, -200, -200C, -300, -400, and -500 series airplanes. The 
NPRM published in the Federal Register on November 30, 2015 (80 FR 
74731) (``the NPRM''). The NPRM was prompted by an evaluation by the 
DAH indicating that the aft pressure bulkhead is subject to WFD. The 
NPRM proposed to require repetitive inspections of the aft pressure 
bulkhead web for any cracking, incorrectly drilled fastener holes, and 
elongated fastener holes, and related investigative and corrective 
actions, if necessary. We are issuing this AD to detect and correct 
fatigue cracking of the aft pressure bulkhead web at the ``Y''-chord, 
which could result in reduced structural integrity of the airplane and 
rapid decompression of the fuselage.

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.

Effect of Winglets on Accomplishment of the Proposed Actions

    Aviation Partners Boeing stated that the installation of winglets 
per supplemental type certificate (STC) ST01219SE does not affect the 
accomplishment of the manufacturer's service instructions.
    We agree with the commenter. We have redesignated paragraph (c) of 
the NPRM as paragraph (c)(1) in this final rule and added a new 
paragraph (c)(2) to state that STC ST01219SE does not affect the 
mitigating action or accomplishment of the actions required by this 
final rule. 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 39.71.

Request To Clarify the Proposed Requirements of the NPRM

    Mr. Cas Lausberg stated that the subject of the NPRM is addressed 
in AD 99-08-23, Amendment 39-11132 (64 FR 19879, April 23, 1999) (``AD 
99-08-23''), which was superseded by AD 2012-18-13 R1, Amendment 39-
17429 (78 FR 27020, May 9, 2013) (``AD 2012-18-13 R1''). The commenter 
questioned the need for the new NPRM.
    We agree to provide clarification. As stated in the ``Discussion'' 
section of the NPRM, this final rule is being issued as part of the 
overall joint effort by Boeing and the FAA to satisfy requirements of 
the FAA's WFD final rule (75 FR 69746, November 15, 2010), which became 
effective on January 14, 2011. The inspections required by AD 99-08-23 
and AD 2012-18-13 R1 do not address WFD concerns. However, Boeing Alert 
Service Bulletin 737-53A1214, Revision 5, dated January 30, 2015, 
addresses WFD with new inspection requirements, which incorporate a 
compliance time (threshold) corresponding to the WFD inspection start 
point (ISP) and shorter repetitive intervals where indicated. These 
requirements are included in this AD. We have not changed this AD in 
this regard.

Request To Revise the Term ``Global Fatigue Damage''

    Boeing requested that the term ``global fatigue damage'' be changed 
to ``widespread fatigue damage'' in the NPRM. Boeing stated that this 
is the first time it has seen the term ``global'' used to describe WFD. 
Boeing commented that it is better not to introduce a new term.
    We agree with the commenter. Although the ``Discussion'' section of 
the proposed rule is not carried over into the final rule, we agree 
that the term ``global fatigue damage'' should not be introduced as a 
new term. We have not changed this AD in this regard.

Request To Correct Reference to Group 1 LOV (Limit of Validity)

    Boeing requested that we change the wording in the ``Differences 
Between This Proposed AD and the Service Information'' paragraph of the 
NPRM, which referred to WFD-based inspections specified in certain 
tables of Boeing Alert Service Bulletin 737-53A1214, Revision 5, dated 
January 30, 2015. The NPRM stated that the WFD-based inspections would 
affect only Group 2 airplanes because Group 1 airplanes will reach 
their LOV before the compliance times specified ``in tables 9, 10, and 
11'' of Boeing Alert Service Bulletin 737-53A1214, Revision 5, dated 
January 30, 2015.
    Boeing stated that the inspections listed in tables 9, 10, and 11 
of Boeing Alert Service Bulletin 737-53A1214, Revision 5, dated January 
30, 2015, also include non-WFD inspections that are required prior to 
the ISP threshold of 76,000 cycles. Boeing stated that, therefore, it 
is not true to say that Group 1 airplanes will reach their limit of 
validity before the compliance times specified in tables 9, 10 and 11.
    We partially agree with the commenter. Although the ``Differences 
Between This Proposed AD and the Service Information'' paragraph of the 
proposed rule is not carried over into the final rule, we agree to 
provide clarification.
    Since AD 2012-18-13 R1 was issued, Boeing issued Alert Service 
Bulletin 737-53A1214, Revision 5, dated January 30, 2015. Affected 
airplanes are now divided into two groups: Group 1, line numbers 1 
through 2565 inclusive; and Group 2, line numbers 2566 through

[[Page 72513]]

3132 inclusive. Boeing's evaluation determined that inspections to 
address WFD concerns are required for the aft pressure bulkhead web at 
the ``Y'' chord at an ISP of 76,000 total flight cycles. Since Group 1 
airplanes will reach their LOV of 75,000 total flight cycles (34,000 
total flight cycles for line numbers 1 through 291 inclusive), which is 
prior to this ISP, no WFD inspections are provided for those airplanes. 
For Group 2 airplanes, which have an LOV of 85,000 total flight cycles, 
new tables 9, 10, and 11 of Boeing Alert Service Bulletin 737-53A1214, 
Revision 5, dated January 30, 2015, include inspections to address WFD. 
We have not changed this AD in this regard.

Request To Clarify the Applicability

    Boeing requested that we clarify the applicability of the proposed 
AD. Boeing stated that Model 737-100, -200, and -200C airplanes should 
be removed from the ``Applicability'' paragraph. Boeing stated that the 
Group 2 airplanes only include Model 737-300, -400, and -500 airplanes.
    We agree with the commenter's request for the reasons stated above. 
We have revised the applicability in paragraph (c) of this AD to remove 
Model 737-100, -200, and -200C series airplanes and revised the SUMMARY 
section to specify certain Model 737-300, -400, and -500 series 
airplanes.

Request To Clarify Airplanes Affected by Terminating Action Provisions

    Boeing requested that we change the wording for the terminating 
action in paragraph (j) of the proposed AD. Boeing stated that the 
paragraph should specify that the terminating action applies only to 
Group 2 airplanes. Boeing stated that specifying Group 2 airplanes 
clearly states the intent of the terminating action.
    We agree with the commenter's request for the reasons stated above. 
We have expanded the structure of paragraph (j) of this AD accordingly. 
In addition, we have clarified that the terminating action does not 
apply to stringer S-5L to S-7L and stringer S-5R to S-9R, as specified 
in AD 2012-18-13 R1 and Boeing Alert Service Bulletin 737-53A1214, 
Revision 5, dated January 30, 2015.

Request To Revise the Inspections for Group 2 Airplanes

    All Nippon Airways (ANA) requested that we revise the inspection 
requirements in the proposed AD for Group 2 airplanes. ANA requested 
that we either mandate the inspections in tables 10 and 11 of Boeing 
Alert Service Bulletin 737-53A1214, Revision 5, dated January 30, 2015, 
for only Group 2 airplanes with 76,000 flight cycles and more, or 
create a new NPRM to supersede AD 2012-18-13 R1 to mandate all 
inspection requirements using Boeing Alert Service Bulletin 737-
53A1214, Revision 5, dated January 30, 2015. ANA stated that if a new 
proposed rule is created, it requests that credit be given for any 
previously approved AMOCs to AD 2012-18-13 R1, to reduce additional 
burden for operators and the FAA.
    We agree with the commenter's request for the reasons stated by the 
commenter. The intent of this final rule is to address the WFD concerns 
in accordance with the FAA's WFD final rule (75 FR 69746, November 15, 
2010). We have revised paragraphs (g), (h), and (l) of this AD 
accordingly.

Additional Changes to This AD

    In paragraphs (g) and (h) of this AD, we have clarified the 
compliance times by explicitly stating the compliance times instead of 
referring to the compliance tables in paragraph 1.E., ``Compliance,'' 
of Boeing Alert Service Bulletin 737-53A1214, Revision 5, dated January 
30, 2015.
    The actions in paragraph (h) of the proposed AD states to do 
detailed and eddy current inspections of the aft pressure bulkhead web 
from the forward or aft side of the bulkhead for any cracking, 
incorrectly drilled fastener hole, and elongated fastener hole. In this 
AD, we have clarified the actions by providing the operators the option 
of doing detailed and LFEC inspections from the aft side of the aft 
pressure bulkhead, or doing a detailed and HFEC inspections from the 
forward side of the aft pressure bulkhead, for any cracking, 
incorrectly drilled fastener hole, and elongated fastener hole.

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 737-53A1214, Revision 5, 
dated January 30, 2015. The service information describes procedures 
for, among other actions, repetitive inspections of the aft pressure 
bulkhead web for any cracking, incorrectly drilled fastener holes, and 
elongated fastener holes; 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 122 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
----------------------------------------------------------------------------------------------------------------
Inspections of the web at the    Up to 60 work-hours x                $0   Up to $5,100 per    Up to $622,200
 ``Y''-chord.                     $85 per hour = Up to                      inspection cycle.   per inspection
                                  $5,100 per inspection                                         cycle.
                                  cycle.
----------------------------------------------------------------------------------------------------------------

    We have received no definitive data that will enable us to provide 
cost estimates for the on-condition actions specified in this AD.

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:

[[Page 72514]]

``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):

2016-20-02 The Boeing Company: Amendment 39-18668; Docket No. FAA-
2015-6538; Directorate Identifier 2015-NM-031-AD.

(a) Effective Date

    This AD is effective November 25, 2016.

(b) Affected ADs

    This AD affects AD 2012-18-13 R1, Amendment 39-17429 (78 FR 
27020, May 9, 2013) (``AD 2012-18-13 R1'').

(c) Applicability

    (1) This AD applies to The Boeing Company Model 737-300, -400, 
and -500 series airplanes, certificated in any category, identified 
as Group 2 in Boeing Alert Service Bulletin 737-53A1214, Revision 5, 
dated January 30, 2015.
    (2) Installation of Supplemental Type Certificate (STC) 
ST01219SE (http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgstc.nsf/0/EBD1CEC7B301293E86257CB30045557A?OpenDocument&Highlight=st01219s) 
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 an evaluation by the design approval 
holder indicating that the aft pressure bulkhead is subject to 
widespread fatigue damage. We are issuing this AD to detect and 
correct fatigue cracking of the aft pressure bulkhead web at the 
``Y''-chord, which could result in reduced structural integrity of 
the airplane and rapid decompression of the fuselage.

(f) Compliance

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

(g) Repetitive Inspections of the Aft Pressure Bulkhead Web at the 
``Y''-Chord Upper Bulkhead

    Within 76,000 total flight cycles, or within 4,500 flight cycles 
since the most recent low frequency eddy current (LFEC) inspection 
accomplished in accordance with AD 2012-18-13 R1, or within 9,500 
flight cycles since the most recent high frequency eddy current 
(HFEC) inspection accomplished in accordance with AD 2012-18-13 R1, 
whichever occurs latest: Do detailed and LFEC inspections from the 
aft side of the aft pressure bulkhead web, or do detailed and HFEC 
inspections from the forward side of the aft pressure bulkhead web, 
for any cracking, incorrectly drilled fastener hole, and elongated 
fastener hole, and do all applicable related investigative and 
corrective actions, in accordance with Part I of the Accomplishment 
Instructions of Boeing Alert Service Bulletin 737-53A1214, Revision 
5, dated January 30, 2015, except as required by paragraph (i) of 
this AD. Do all related investigative and corrective actions before 
further flight. If any cracking, incorrectly drilled fastener hole, 
or elongated fastener hole is found, before further flight, repair 
the aft pressure bulkhead web using a method approved in accordance 
with the procedures specified in paragraph (l) of this AD. 
Thereafter, repeat the inspections at the applicable times specified 
in table 10 of paragraph 1.E., ``Compliance'' of Boeing Alert 
Service Bulletin 737-53A1214, Revision 5, dated January 30, 2015.

(h) Repetitive Inspections of the Aft Pressure Bulkhead Web at the 
``Y''-Chord Below S-15

    Within 76,000 total flight cycles, or within 4,500 flight cycles 
since the most recent LFEC inspection accomplished in accordance 
with AD 2012-18-13 R1, or within 9,500 flight cycles since the most 
recent HFEC inspection accomplished in accordance with AD 2012-18-13 
R1, whichever occurs latest: Do detailed and LFEC inspections from 
the aft side of the aft pressure bulkhead, or do detailed and HFEC 
inspections from the forward side of the aft pressure bulkhead, for 
any cracking, incorrectly drilled fastener hole, and elongated 
fastener hole, and do all applicable corrective actions, in 
accordance with Part III of the Accomplishment Instructions of 
Boeing Alert Service Bulletin 737-53A1214, Revision 5, dated January 
30, 2015, except as required by paragraph (i) of this AD. Do all 
corrective actions before further flight. If any cracking, 
incorrectly drilled fastener hole, or elongated fastener hole is 
found, before further flight, repair the aft pressure bulkhead web 
using a method approved in accordance with the procedures specified 
in paragraph (l) of this AD. Thereafter, repeat the inspections at 
the applicable times specified in table 11 of paragraph 1.E., 
``Compliance,'' of Boeing Alert Service Bulletin 737-53A1214, 
Revision 5, dated January 30, 2015.

(i) Exception to the Service Information

    Where Boeing Alert Service Bulletin 737-53A1214, Revision 5, 
dated January 30, 2015, specifies to contact Boeing for repair 
instructions: Before further flight, repair using a method approved 
in accordance with the procedures specified in paragraph (l) of this 
AD.

(j) Terminating Action for Other Rulemaking

    (1) For Group 2 airplanes specified in Boeing Alert Service 
Bulletin 737-53A1214, Revision 5, dated January 30, 2015: 
Accomplishing the actions required by paragraph (g) of this AD 
terminates the inspections required by paragraph (k) of AD 2012-18-
13 R1, except for stringer S-5L to S-7L and stringer S-5R to S-9R.
    (2) For Group 2 airplanes specified in Boeing Alert Service 
Bulletin 737-53A1214, Revision 5, dated January 30, 2015: 
Accomplishing the actions required by paragraph (h) of this AD 
terminates the inspections required by paragraph (l) of AD 2012-18-
13 R1.

(k) Credit for Previous Actions

    This paragraph provides credit for the actions required by 
paragraphs (g) and (h) of this AD, if the actions were performed 
before the effective date of this AD using Boeing Alert Service 
Bulletin 737-53A1214, Revision 4, dated December 16, 2011.

[[Page 72515]]

(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)(1) 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) 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 previously for AD 2012-18-13 R1, Amendment 
39-17429 (78 FR 27020, May 9, 2013), are approved as AMOCs for the 
corresponding provisions of this AD.

(m) Related Information

    (1) For more information about this AD, contact Payman Soltani, 
Aerospace Engineer, Airframe Branch, ANM-120L, FAA, Los Angeles ACO, 
3960 Paramount Boulevard, Lakewood CA 90712-4137; telephone: 562-
627-5313; fax: 562-627-5210; email: payman.soltani@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 (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 737-53A1214, Revision 5, dated 
January 30, 2015.
    (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 September 16, 2016.
Thomas Groves,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2016-23078 Filed 10-19-16; 8:45 am]
BILLING CODE 4910-13-P


