
[Federal Register Volume 82, Number 106 (Monday, June 5, 2017)]
[Proposed Rules]
[Pages 25744-25746]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2017-11257]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2017-0526; Directorate Identifier 2017-NM-026-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 adopt a new airworthiness directive (AD) for all 
The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 
series airplanes. This proposed AD was prompted by reports of cracking 
in the upper aft skin at the rear spar of the wings. This proposed AD 
would require repetitive inspections for cracking of the upper aft skin 
of the wings, and repair 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 July 20, 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-2017-0526.

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-2017-
0526; 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

[[Page 25745]]

ADDRESSES section. Include ``Docket No. FAA-2017-0526; Directorate 
Identifier 2017-NM-026-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

    We have received reports of cracking in the upper aft skin at the 
rear spar of the wings on Model 737-200, -200C, -300, -400, and -500 
series airplanes. One operator found a crack originating from a 
fastener hole common to the upper aft skin and strap aft of the rear 
spar at wing buttock line (WBL) 187. The airplane had accumulated 
49,461 flight hours and 47,718 flight cycles. A total of 73 cases of 
upper aft skin cracks were reported between 1993 and 2015; the cracks 
measured from 0.02 to 3.0 inches long. Cracks between WBL 159 and WBL 
200 were found during open-hole high frequency eddy current (HFEC) 
inspections of a previous repair of the upper chord splice of the wing 
rear spar. The majority of larger cracks were found at WBL 171, 183, 
187, and 200 at the end fasteners common to the straps attaching the 
wing trailing edge to the wing upper aft skin. This condition, if not 
corrected, could result in the inability of a principal structural 
element to sustain limit load, and consequent reduced structural 
integrity of the airplane.

Explanation of Applicability

    Model 737-100, -200, and -200C series airplanes having line numbers 
1 through 291 have a limit of validity (LOV) of 34,000 total flight 
cycles, and the actions proposed in this NPRM, as specified in Boeing 
Alert Service Bulletin 737-57A1329, dated January 16, 2017, would be 
required at a compliance time occurring after that LOV. Although 
operation of an airplane beyond its LOV is prohibited by 14 CFR 
121.1115 and 129.115, this NPRM includes those airplanes in the 
applicability so that they are tracked in the event the LOV is extended 
in the future.

Related Service Information Under 1 CFR Part 51

    We reviewed Boeing Alert Service Bulletin 737-57A1329, dated 
January 16, 2017. The service information describes procedures for 
repetitive surface HFEC, low frequency eddy current, and detailed 
inspections on airplanes with or without an external repair, for 
cracking of the upper aft skin from WBL 159 to WBL 220. 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

    This proposed AD would require accomplishing the actions specified 
in the service information described previously. 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-2017-
0526.

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
----------------------------------------------------------------------------------------------------------------
                                                                                                 Cost on U.S.
              Action                    Labor cost        Parts cost      Cost per product        operators
----------------------------------------------------------------------------------------------------------------
Inspection.......................  Up to 9 work-hours               $0  Up to $765 per       Up to $360,315 per
                                    x $85 per hour =                     inspection cycle.    inspection cycle
                                    up to $765 per
                                    inspection cycle.
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    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 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 this 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:

[[Page 25746]]

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):

The Boeing Company: Docket No. FAA-2017-0526; Directorate Identifier 
2017-NM-026-AD.

(a) Comments Due Date

    We must receive comments by July 20, 2017.

(b) Affected ADs

    None.

(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 cracking in the upper aft 
skin at the rear spar of the wings. We are issuing this AD to detect 
and correct cracks in the upper aft skin of the wings, which could 
result in the inability of a principle structural element to sustain 
limit load, and consequent reduced structural integrity of the 
airplane.

(f) Compliance

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

(g) For Group 1 Airplanes: Inspections

    For airplanes identified as Group 1 in Boeing Alert Service 
Bulletin 737-57A1329, dated January 16, 2017: Within 120 days after 
the effective date of this AD, do an inspection for cracking of the 
upper aft skin of the wings, using a method approved in accordance 
with the procedures specified in paragraph (j) of this AD.

(h) For Groups 2 and 3 Airplanes: Repetitive Inspections and Repair

    For Groups 2 and 3 airplanes identified in Boeing Alert Service 
Bulletin 737-57A1329, dated January 16, 2017: At the applicable time 
specified in paragraph 1.E., ``Compliance,'' of Boeing Alert Service 
Bulletin 737-57A1329, dated January 16, 2017, except as required by 
paragraph (i) of this AD, do the applicable inspection for cracking 
of the upper aft skin of the wings from wing buttock line (WBL) 159 
to WBL 220, in accordance with the Work Instructions of Boeing Alert 
Service Bulletin 737-57A1329, dated January 16, 2017. If any 
cracking is found, repair before further flight, in accordance with 
the procedures specified in paragraph (j) of this AD. Repeat the 
inspection thereafter at the applicable time specified in paragraph 
1.E., ``Compliance,'' of Boeing Alert Service Bulletin 737-57A1329, 
dated January 16, 2017.

(i) Exceptions to the Service Information

    (1) Where Boeing Alert Service Bulletin 737-57A1329, dated 
January 16, 2017, specifies a compliance time ``after the original 
issue date of this service bulletin,'' paragraph (h) of this AD 
requires compliance within the specified compliance time after the 
effective date of this AD.
    (2) Although Boeing Alert Service Bulletin 737-57A1329, dated 
January 16, 2017, specifies to contact Boeing for repair 
instructions, and specifies that action as ``RC'' (Required for 
Compliance), this AD requires repair in accordance with the 
procedures specified in paragraph (j) of this AD.

(j) 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 (k)(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 (i)(2) of this AD: For 
service information that contains steps that are labeled as Required 
for Compliance (RC), the provisions of paragraphs (j)(4)(i) and 
(j)(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 substep is labeled ``RC Exempt,'' then the 
RC requirement is removed from that step or substep. 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.

(k) 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 May 23, 2017.
Michael Kaszycki,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2017-11257 Filed 6-2-17; 8:45 am]
 BILLING CODE 4910-13-P


