
[Federal Register Volume 82, Number 3 (Thursday, January 5, 2017)]
[Proposed Rules]
[Pages 1254-1258]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-31367]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2016-9523; Directorate Identifier 2016-NM-134-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) 2014-12-
13, which applies to all The Boeing Company Model 737-100, -200, -200C, 
-300, -400, and -500 series airplanes. AD 2014-12-13 currently requires 
repetitive inspections for cracking of the main landing gear (MLG) 
beam, and the

[[Page 1255]]

rear spar upper chord and rear spar web; and repair if necessary. Since 
we issued AD 2014-12-13, we received reports of additional cracking in 
the inspar upper skin, rear spar web and rear spar upper chord. This 
proposed AD would expand the inspection area and add related 
investigative and corrective actions if necessary. We are proposing 
this AD to address the unsafe condition on these products.

DATES: We must receive comments on this proposed AD by February 21, 
2017.

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: 202-493-2251.
     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: Contractual & Data Services (C&DS), 
2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 90740; 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-2016-9523.

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-
9523; 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: 800-647-5527) is in the ADDRESSES section. Comments will 
be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT: Payman Soltani, Aerospace Engineer, 
Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification 
Office (ACO), 3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 
562-627-5313; fax: 562-627-5210; email: payman.soltani@faa.gov.

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-2016-9523; 
Directorate Identifier 2016-NM-134-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

    On June 6, 2014, we issued AD 2014-12-13, Amendment 39-17874 (79 FR 
39300, July 10, 2014) (``AD 2014-12-13''), for all The Boeing Company 
Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. AD 
2014-12-13 requires repetitive inspections for cracking of the aft 
support fitting for the MLG beam, the rear spar upper chord and rear 
spar web in the area of rear spar station (RSS) 224.14; and repair if 
necessary. AD 2014-12-13 resulted from reports of cracks found in the 
aft support fitting, the rear spar upper chord, and the rear spar web. 
We issued AD 2014-12-13 to detect and correct cracking of the aft 
support fitting for the MLG beam, the rear spar upper chord and rear 
spar web in the area of RSS 224.14, which could grow and result in a 
fuel leak and possible fire.

Other Related Rulemaking

    On October 11, 2015, we issued AD 2015-21-08, Amendment 39-18301 
(80 FR 65921, October 28, 2015) (``AD 2015-21-08''), for certain The 
Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series 
airplanes. AD 2015-21-08 was prompted by a report that an operator 
discovered a crack in a certain section of the inspar upper skin, just 
forward of the rear spar on the right wing. AD 2015-21-08 requires 
repetitive eddy current inspections for any cracking in the inspar 
upper skin, and related investigative and corrective actions if 
necessary. We issued AD 2015-21-08 to detect and correct any cracking 
in the inspar upper skin and rear spar upper chord, which could result 
in the inability of the structure to carry limit load, or result in a 
fuel leak, which could prevent continued safe flight and landing.

Actions Since AD 2014-12-13 and 2015-21-08 Were Issued

    Since we issued AD 2014-12-13 and AD 2015-21-08, an operator 
discovered a 2.375-inch-long crack in the inspar upper skin at wing 
buttock line (WBL) 157, just forward of the rear spar on the right wing 
and adjacent to the inspection area specified in Boeing Special 
Attention Service Bulletin 737-57-1318, dated May 15, 2013 (the source 
of service information for the actions required by AD 2014-12-13). Two 
additional smaller cracks were found in the skin at two holes common to 
the rear spar in the same area. Subsequent inspections revealed that 
the right rear spar upper chord was almost completely severed and the 
left rear spar chord was completely severed. Rear spar web cracks were 
also noted on both wings. The affected airplane had accumulated 51,548 
total flight cycles.
    After the initial report of the inspar upper skin crack, additional 
reports of inspar upper skin cracking were found in the same area. 
Inspar upper skin cracking at this location is the subject of AD 2015-
21-08, which correlates with Boeing Alert Service Bulletin 737-57A1326, 
dated September 22, 2015; and Boeing Alert Service Bulletin 737-
57A1328, dated July 22, 2016. Although skin cracking is addressed 
outside of Boeing Special Attention Service Bulletin 737-57-1318, dated 
May 15, 2013, analysis shows that rear spar upper chord cracking can 
negatively influence the inspar upper skin cracking condition. In 
addition to influencing skin cracking, rear spar upper chord cracking 
can also influence cracking at other mating structures.
    In addition, since Boeing Alert Service Bulletin 737-57A1318, dated 
May 15, 2013, has been issued, multiple operators have also reported 
cracking in the MLG beam forward support fitting, which was found while 
doing repairs to address cracked chords. Therefore, the MLG beam 
forward support fitting has been added to the inspection area, and the 
inspection threshold and intervals have been shortened, as specified in 
Boeing Alert Service Bulletin 737-57A1318, Revision 1, dated July 22, 
2016.

[[Page 1256]]

Related Service Information Under 1 CFR Part 51

    We reviewed Boeing Alert Service Bulletin 737-57A1318, Revision 1, 
dated July 22, 2016. The service information describes procedures for 
repetitive high frequency eddy current (HFEC) open hole inspections for 
any cracking in the forward support fitting, the aft support fitting, 
the rear spar upper chord, and the rear spar web at the 12 fastener 
holes (locations 1-12). The service information also describes the 
option of HFEC open hole inspections for any cracking in the forward 
support fitting and the aft support fitting, and HFEC surface 
inspections for any cracking in the rear spar upper chord and rear spar 
upper web, as applicable, and related investigative and corrective 
actions.
    We also reviewed Boeing Alert Service Bulletin 737-57A1328, dated 
July 22, 2016. The service information describes procedures for 
repetitive eddy current inspections of the left and right wing for any 
cracking in the inspar upper skin and the repair parts if applicable, 
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.

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 2014-12-13, this proposed AD would retain all of the 
requirements of AD 2014-12-13. 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 also 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-2016-9523.
    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 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 Alert Service Bulletin 737-57A1318, Revision 1, dated July 
22, 2016; and Boeing Alert Service Bulletin 737-57A1328, dated July 22, 
2016; specify to contact the manufacturer for certain instructions, but 
this proposed AD would require accomplishment of repair methods, 
modification deviations, and alteration deviations 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.

Costs of Compliance

    We estimate that this proposed AD affects 471 airplanes of U.S. 
registry. We estimate the following costs to comply with this proposed 
AD:

                                                 Estimated Costs
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                                                             Parts                              Cost on U.S.
              Action                      Labor cost         cost       Cost per product          operators
----------------------------------------------------------------------------------------------------------------
HFEC open hole inspections........  82 work-hours x $85          $0  $6,970 per inspection  $3,282,870 per
                                     per hour = $6,970                cycle.                 inspection cycle.
                                     per inspection cycle.
Eddy current inspection...........  14 work-hours x $85           0  $1,190 per inspection  $560,490 per
                                     per hour = $1,190                cycle.                 inspection cycle.
                                     per inspection cycle.
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                  Estimated Costs for Optional Actions
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                                                 Parts       Cost per
           Action                Labor cost      cost        product
------------------------------------------------------------------------
Inspection..................  Up to 41 work-         $0  Up to
                               hours x $85                $1,641,435 per
                               per hour =                 inspection
                               $3,485 per                 cycle.
                               inspection
                               cycle.
------------------------------------------------------------------------

    We have received no definitive data that would enable us to provide 
cost estimates for the on-condition actions specified in this proposed 
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, ``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

[[Page 1257]]

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) 
2014-12-13, Amendment 39-17874 (79 FR 39300, July 10, 2014), and adding 
the following new AD:

The Boeing Company: Docket No. FAA-2016-9523; Directorate Identifier 
2016-NM-134-AD.

(a) Comments Due Date

    The FAA must receive comments on this AD action by February 21, 
2017.

(b) Affected ADs

    This AD replaces AD 2014-12-13, Amendment 39-17874 (79 FR 39300, 
July 10, 2014). This AD affects AD 2015-21-08, Amendment 39-18301 
(80 FR 65921, October 28, 2015).

(c) Applicability

    This AD applies to all The Boeing Company Model 737-100, -200, -
200C, -300, -400, and -500 series airplanes, certificated in any 
category.

(d) Subject

    Air Transport Association (ATA) of America Code 57, Wings.

(e) Unsafe Condition

    This AD was prompted by reports of additional cracking in the 
inspar upper skin at Wing Buttock Line (WBL) 157 and in the skin at 
two holes common to the rear spar in the same area, and rear spar 
web cracks were also noted on both wings. Subsequent inspections 
revealed that the right rear spar upper chord was almost completely 
severed and the left rear spar upper chord was completely severed. 
We are issuing this AD to detect and correct cracking of the forward 
and aft support fittings for the main landing gear (MLG) beam, the 
rear spar upper chord and rear spar web in the area of rear spar 
station (RSS) 224.14, which could grow and result in a fuel leak and 
possible fire.

(f) Compliance

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

(g) Required Actions for Group 1 Airplanes

    For airplanes identified as Group 1 in Boeing Alert Service 
Bulletin 737-57A1318, Revision 1, dated July 22, 2016: At the 
applicable time specified in table 1 of paragraph 1.E., 
``Compliance,'' of Boeing Alert Service Bulletin 737-57A1318, 
Revision 1, dated July 22, 2016, except as required by paragraph 
(j)(3) of this AD, do applicable inspections and corrective actions 
using a method approved in accordance with the procedures specified 
in paragraph (m) of this AD.

(h) Required Actions for Groups 2-7 Airplanes

    For airplanes identified as Groups 2-7 in Boeing Alert Service 
Bulletin 737-57A1318, Revision 1, dated July 22, 2016: At the 
applicable time specified in table 2 through table 9 of paragraph 
1.E., ``Compliance,'' of Boeing Alert Service Bulletin 737-57A1318, 
Revision 1, dated July 22, 2016, except as required by paragraph 
(j)(3) of this AD: Do high frequency eddy current (HFEC) open hole 
inspections for any cracking in the forward support fitting, the aft 
support fitting, the rear spar upper chord, and the rear spar web at 
the 12 fastener holes (locations 1-12); or HFEC open hole 
inspections for any cracking in the forward support fitting and the 
aft support fitting, and HFEC surface inspection for any cracking in 
the rear spar upper chord and rear spar upper web; as applicable, 
and do all applicable related investigative and corrective actions, 
in accordance with the Accomplishment Instructions of Boeing Alert 
Service Bulletin 737-57A1318, Revision 1, dated July 22, 2016. Do 
all applicable related investigative and corrective actions before 
further flight. Thereafter, repeat the HFEC inspection at the 
applicable time specified in table 2 through table 9 of paragraph 
1.E., ``Compliance,'' of Boeing Alert Service Bulletin 737-57A1318, 
Revision 1, dated July 22, 2016. Options provided in Boeing Alert 
Service Bulletin 737-57A1318, Revision 1, dated July 22, 2016, for 
accomplishing the inspection are acceptable for the corresponding 
requirements of this paragraph provided that the inspections are 
done at the applicable times in paragraph 1.E., ``Compliance,'' of 
Boeing Alert Service Bulletin 737-57A1318, Revision 1, dated July 
22, 2016.

(i) Eddy Current Inspection

    For airplanes identified in Boeing Alert Service Bulletin 737-
57A1328, dated July 22, 2016: At the applicable time specified in 
table 1 and table 2 of paragraph 1.E., ``Compliance,'' of Boeing 
Alert Service Bulletin 737-57A1328, dated July 22, 2016, except as 
required by paragraph (j)(2) of this AD, do an eddy current 
inspection of the left and right wings for any cracking in the 
inspar upper skin, and at the repair parts if applicable, and do all 
applicable related investigative and corrective actions, in 
accordance with the Accomplishment Instructions of Boeing Alert 
Service Bulletin 737-57A1328, dated July 22, 2016. Do all related 
investigative and corrective actions before further flight. 
Thereafter, repeat the eddy current inspection at the applicable 
time specified in table 1 and table 2 of paragraph 1.E., 
``Compliance,'' of Boeing Alert Service Bulletin 737-57A1328, dated 
July 22, 2016.

(j) Exceptions to the Service Information

    (1) If any cracking is found during any inspection required by 
this AD, and Boeing Alert Service Bulletin 737-57A1328, dated July 
22, 2016, specifies to contact Boeing for appropriate action: Before 
further flight, repair using a method approved in accordance with 
the procedures specified in paragraph (m) of this AD.
    (2) Where Boeing Alert Service Bulletin 737-57A1328, dated July 
22, 2016, specifies a compliance time ``after the Original Issue 
date of this service bulletin,'' paragraph (i) of this AD requires 
compliance within the specified compliance time after the effective 
date of this AD.
    (3) Where Boeing Alert Service Bulletin 737-57A1318, Revision 1, 
dated July 22, 2016, specifies a compliance time ``after the 
Revision 1 date of this service bulletin, whichever occurs later,'' 
paragraphs (g) and (h) of this AD require compliance within the 
specified compliance time after the effective date of this AD.

(k) Terminating Action

    Accomplishing the initial inspections and applicable related 
investigative and corrective actions required by paragraphs (g), 
(h), and (i) of this AD, as applicable, in accordance with the 
Accomplishment Instructions of Boeing Alert Service Bulletin 737-
57A1318, Revision 1, dated July 22, 2016; and Boeing Alert Service 
Bulletin 737-57A1328, dated July 22, 2016, terminates all 
requirements of AD 2015-21-08.

(l) Credit for Previous Actions

    This paragraph provides credit for the actions specified in 
paragraphs (g) and (h) of this AD, if those actions were performed 
before the effective date of this AD using Boeing Alert Service 
Bulletin 737-57A1318, May 15, 2013, which was incorporated by 
reference in AD 2014-03-06, Amendment 39-17743 (79 FR 39300, July 
10, 2014).

[[Page 1258]]

(m) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Los Angeles Aircraft Certification Office 
(ACO), ANM-120L, 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 (n)(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) Except as required by paragraph (j) of this AD: For service 
information that contains steps that are labeled as Required for 
Compliance (RC), the provisions of paragraphs (m)(4)(i) and 
(m)(4)(ii) of this AD apply.
    (i) The steps labeled as RC, including substeps under an RC step 
and any figures identified in an RC step, must be done to comply 
with the AD. If a step or sub-step is labeled ``RC Exempt,'' then 
the RC requirement is removed from that step or sub-step. An AMOC is 
required for any deviations to RC steps, including substeps and 
identified figures.
    (ii) Steps not labeled as RC may be deviated from using accepted 
methods in accordance with the operator's maintenance or inspection 
program without obtaining approval of an AMOC, provided the RC 
steps, including substeps and identified figures, can still be done 
as specified, and the airplane can be put back in an airworthy 
condition.

(n) 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; phone: 562-627-
5313; fax: 562-627-5210; email: payman.soltani@faa.gov.
    (2) For 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; 
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.

    Issued in Renton, Washington, on December 16, 2016.
Ross Landes,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2016-31367 Filed 1-4-17; 8:45 am]
BILLING CODE 4910-13-P


