
[Federal Register Volume 82, Number 156 (Tuesday, August 15, 2017)]
[Proposed Rules]
[Pages 38623-38626]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2017-16780]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2017-0776; Product Identifier 2017-NM-062-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 
certain The Boeing Company Model 737-200, -300, -400, and -500 series 
airplanes. This proposed AD was prompted by reports of cracks in the 
frame web adjacent to the air-conditioning support brackets. This 
proposed AD would require an inspection for any air conditioning 
bracket assembly or intercostal, and depending on the results, 
repetitive inspections for cracking of certain locations and applicable 
on-condition actions. We are proposing this AD to address the unsafe 
condition on these products.

[[Page 38624]]


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-2017-0776.

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-
0776; 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: Alan Pohl, Aerospace Engineer, 
Airframe Section, FAA, Seattle ACO Branch, 1601 Lind Avenue SW., 
Renton, WA 98057-3356; phone: 425-917-6450; fax: 425-917-6590; email: 
alan.pohl@faa.gov.

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-2017-0776; 
Product Identifier 2017-NM-062-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 operators have found 
cracks in the frame web adjacent to the air-conditioning support 
brackets. One crack was found in the outboard fastener hole common to 
the stringer tie for stringer S-8R at station (STA) 380 with a crack 
size 0.35 inch, at 35,889 total flight cycles. Another crack was found 
in the outboard fastener hole common to the stringer tie for stringer 
S-8L at STA 907 with a crack size 0.20 inch, at 28,165 total flight 
cycles. The frame web cracks are due to fatigue caused by the stringer 
tie reacting to frame twisting that is the result of the air-
conditioning bracket binding within the slip joint assembly. This 
binding results in out-of-plane (forward-aft) loads being placed onto 
the frame and occurs because of thermal expansion of the air 
conditioning rail as well as fuselage deflection during flight 
transmitting loads into the rail. Such cracks, if not corrected, could 
result in a severed frame. A severed frame, in combination with 
potential multiple site damage (MSD) at the stringer S-10 lap splice or 
chem-mill skin cracks, can result in possible rapid decompression and 
loss of structural integrity of the airplane.

Related Service Information Under 1 CFR Part 51

    We reviewed Boeing Alert Service Bulletin 737-53A1363, dated April 
7, 2017. The service information describes procedures for an inspection 
for any air-conditioning bracket assembly or intercostal, repetitive 
inspections for cracking of certain locations, and applicable on-
condition 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

    This proposed AD would require accomplishment of the actions 
identified as ``RC'' (required for compliance) in the Accomplishment 
Instructions of Boeing Alert Service Bulletin 737-53A1363, dated April 
7, 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-2017-0776.

Costs of Compliance

    We estimate that this proposed AD affects 302 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
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Inspections..................  27 work-hours x $85                $0   $2,295 per        $693,090 per inspection
                                per hour = $2,295                       inspection        cycle.
                                per inspection cycle.                   cycle.
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[[Page 38625]]

    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.
    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 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-2017-0776; Product Identifier 
2017-NM-062-AD.

(a) Comments Due Date

    We must receive comments by September 29, 2017.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to The Boeing Company Model 737-200, -300, -400, 
and -500 series airplanes, certificated in any category, as 
identified in Boeing Alert Service Bulletin 737-53A1363, dated April 
7, 2017.

(d) Subject

    Air Transport Association (ATA) of America Code 53, Fuselage.

(e) Unsafe Condition

    This AD was prompted by reports of cracks in the frame web 
adjacent to the air-conditioning support brackets. We are issuing 
this AD to detect and correct cracks in the frame web adjacent to 
the air-conditioning support brackets, which could result in a 
severed frame, and in combination with potential multiple site 
damage (MSD) at the stringer S-10 lap splice or chem-mill skin 
cracks, could result in possible rapid decompression and loss of 
structural integrity of the airplane.

(f) Compliance

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

(g) Required Actions

    Except as required by paragraph (h) of this AD: At the 
applicable times specified in paragraph 1.E., ``Compliance,'' of 
Boeing Alert Service Bulletin 737-53A1363, dated April 7, 2017, do 
all applicable actions identified as ``RC'' (required for 
compliance) in, and in accordance with, the Accomplishment 
Instructions of Boeing Alert Service Bulletin 737-53A1363, dated 
April 7, 2017.

(h) Exceptions to Service Information Specifications

    (1) Where Boeing Alert Service Bulletin 737-53A1363, dated April 
7, 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'' applies.
    (2) Where Boeing Alert Service Bulletin 737-53A1363, dated April 
7, 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 (j) of this AD.

(i) Terminating Action for Repetitive Inspections

    Accomplishment of a reinforcement repair at the stringer tie 
location in accordance with a method approved in accordance with the 
procedures specified in paragraph (j) of this AD terminates the 
repetitive inspections required by paragraph (g) of this AD for the 
repaired stringer tie location only, provided the crack is removed 
or trimmed out from the stringer tie holes.

(j) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Seattle 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 (k)(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 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 (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

[[Page 38626]]

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 Alan Pohl, 
Aerospace Engineer, Airframe Section, FAA, Seattle ACO Branch, 1601 
Lind Avenue SW., Renton, WA 98057-3356; phone: 425-917-6450; fax: 
425-917-6590; email: alan.pohl@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-
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. 2017-16780 Filed 8-14-17; 8:45 am]
BILLING CODE 4910-13-P


