[Federal Register Volume 82, Number 156 (Tuesday, August 15, 2017)]
[Proposed Rules]
[Pages 38641-38643]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2017-16774]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2017-0773; Product Identifier 2017-NM-067-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 cracks 
found in the lower chord of the left wing rear spar. This proposed AD 
would require repetitive inspections for cracking of the lower chord of 
the rear spar and lower aft skin at wing buttock line (WBL) 157 and 
applicable on-condition actions. We are proposing this AD to address 
the unsafe condition on these products.

DATES: We must receive comments on this proposed AD by September 29, 
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 90740-5600; 
telephone 562-797-1717; Internet https://www.myboeingfleet.com. You may 
view this referenced service information at the FAA, Transport 
Standards Branch, 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-2017-0773.

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-
0773; 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 NPRM, 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 Section, FAA, Los Angeles Aircraft Certification Office (ACO)

[[Page 38642]]

Branch, 3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 562-
627-5313; fax: 562-627-5210; email: [email protected].

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to send any written relevant data, views, or 
arguments about this proposal. Send your comments to an address listed 
under the ADDRESSES section. Include ``Docket No. FAA-2017-0773; 
Product Identifier 2017-NM-067-AD'' at the beginning of your comments. 
We specifically invite comments on the overall regulatory, economic, 
environmental, and energy aspects of this NPRM. We will consider all 
comments received by the closing date and may amend this NPRM 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 indicating that a crack was found in the 
horizontal flange of the lower chord of the left wing rear spar at WBL 
157 during a non-destructive test (NDT) at 53,841 total flight cycles 
and 66,268 total flight hours. Similar cracks have been reported on 
other Boeing airplanes that have accumulated between 63,550 and 69,285 
total flight cycles. Analysis has shown that main landing gear (MLG) 
loading and braking loads result in cyclic fatigue and local stresses 
on the structure. Concentrated loading due to the back-to-back design 
of the MLG fitting also contributes to the problem. This condition, if 
not corrected, could lead to the inability of the lower chord of the 
rear spar, a principal structural element, to sustain limit load, which 
could adversely affect the structural integrity of the airplane.

Related Service Information Under 1 CFR Part 51

    We reviewed Boeing Alert Service Bulletin 737-57A1333, dated May 
12, 2017. The service information describes procedures for repetitive 
low frequency eddy current (LFEC) inspections for cracking of the lower 
chord of the rear spar and detailed inspections for cracking of the 
lower aft skin at WBL 157, applicable on-condition actions (e.g., 
repair), and instructions for airplanes that have an existing repair in 
the inspection area. 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 accomplishment of the actions 
identified as ``RC'' (required for compliance) in the Accomplishment 
Instructions of Boeing Alert Service Bulletin 737-57A1333, dated May 
12, 2017, described previously, except for any differences identified 
as exceptions in the regulatory text of this proposed AD.
    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-2017-0773.

Explanation of Applicability

    Model 737 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 
737-57A1333, dated May 12, 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 would 
include those airplanes in the applicability so that these airplanes 
are tracked in the event the LOV is extended in the future.

Costs of Compliance

    We estimate that this proposed AD affects 190 airplanes of U.S. 
registry. We estimate the following costs to comply with this proposed 
AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
            Action                   Labor cost         Parts cost    Cost per product   Cost on U.S. operators
----------------------------------------------------------------------------------------------------------------
LFEC and detailed inspections  10 work-hours x $85                $0  $850 per          Up to $161,500 per
                                per hour = $850 per                    inspection        inspection cycle.
                                inspection cycle.                      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.
    We have received no definitive data that would enable us to provide 
cost estimates for the instructions for airplanes that have an existing 
repair in the inspection area 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.
    This proposed AD is issued in accordance with authority delegated 
by the Executive Director, Aircraft Certification Service, as 
authorized by FAA Order 8000.51C. In accordance with that order, 
issuance of ADs is normally a function of the Compliance and 
Airworthiness Division, but during this transition period, the 
Executive Director has delegated the authority to issue ADs applicable 
to transport category airplanes to the Director of the System Oversight 
Division.

Regulatory Findings

    We determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This

[[Page 38643]]

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:

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-2017-0773; Product Identifier 
2017-NM-067-AD.

(a) Comments Due Date

    We must receive comments by September 29, 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 the report of a crack indication in the 
horizontal flange of the lower chord of the left wing rear spar at 
wing buttock line (WBL) 157 and multiple reports of similar crack 
findings on other airplanes. We are issuing this AD to detect and 
correct cracking of the lower chord of the rear spar and the lower 
aft skin at WBL 157. Undetected cracks could lead to the inability 
of the lower chord of the rear spar, a principal structural element, 
to sustain limit load, which could adversely affect the structural 
integrity of the airplane.

(f) Compliance

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

(g) Required Actions

    (1) For Group 2 airplanes identified in Boeing Alert Service 
Bulletin 737-57A1333, dated May 12, 2017: Except as required by 
paragraph (h) of this AD, at the applicable times specified in 
paragraph 1.E., ``Compliance,'' of Boeing Alert Service Bulletin 
737-57A1333, dated May 12, 2017, do all applicable actions 
identified as ``RC'' (required for compliance) in, and in accordance 
with, the Accomplishment Instructions of Boeing Alert Service 
Bulletin 737-57A1333, dated May 12, 2017.
    (2) For Group 1 airplanes identified in Boeing Alert Service 
Bulletin 737-57A1333, dated May 12, 2017: Within 120 days after the 
effective date of this AD, inspect the airplane and do all 
applicable corrective actions using a method approved in accordance 
with the procedures specified in paragraph (i) of this AD.

(h) Exceptions to Service Information Specifications

    (1) Where Boeing Alert Service Bulletin 737-57A1333, dated May 
12, 2017, uses the phrase ``after the original issue date of this 
service bulletin,'' for purposes of determining compliance with the 
requirements of this AD, the phrase ``after the effective date of 
this AD'' must be used.
    (2) Where Boeing Alert Service Bulletin 737-57A1333, dated May 
12, 2017, specifies contacting Boeing, and specifies that action as 
RC: This AD requires using a method approved in accordance with the 
procedures specified in paragraph (i) of this AD.

(i) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Los Angeles ACO Branch, 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 certification office, send it to the attention of 
the person identified in paragraph (j)(1) of this AD. Information 
may be emailed to: [email protected].
    (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 Branch, 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 (h)(2) of this AD: For 
service information that contains steps that are labeled as RC, the 
provisions of paragraphs (i)(4)(i) and (i)(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.

(j) Related Information

    (1) For more information about this AD, contact Payman Soltani, 
Aerospace Engineer, Airframe Section, FAA, Los Angeles ACO Branch, 
3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 562-627-
5313; fax: 562-627-5210; email: [email protected].
    (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-
5600; telephone 562-797-1717; Internet https://www.myboeingfleet.com. You may view this referenced service 
information at the FAA, Transport Standards Branch, 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 August 2, 2017.
Jeffrey E. Duven,
Director, System Oversight Division, Aircraft Certification Service.
[FR Doc. 2017-16774 Filed 8-14-17; 8:45 am]
 BILLING CODE 4910-13-P