[Federal Register Volume 81, Number 65 (Tuesday, April 5, 2016)]
[Proposed Rules]
[Pages 19512-19514]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-07577]



[[Page 19512]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2016-5042; Directorate Identifier 2015-NM-140-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 737-600, -700, -700C, -800, -900 and -900ER 
series airplanes. This proposed AD was prompted by an evaluation by the 
design approval holder (DAH) indicating that certain fastener locations 
in the window corner surround structure are subject to widespread 
fatigue damage (WFD). This proposed AD would require repetitive high 
frequency eddy current (HFEC) inspections for cracking in certain 
fastener locations in the window corner surround structure, and repair 
if necessary. We are proposing this AD to detect and correct fatigue 
cracking around certain fastener locations that could cause multiple 
window corner skin cracks, which could result in rapid decompression 
and consequent reduced structural integrity of the airplane.

DATES: We must receive comments on this proposed AD by May 20, 2016.

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: 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-2016-
5042.

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-
5042; 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: Jason Deutschman, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office 
(ACO), 1601 Lind Avenue SW., Renton, WA 98057-3356; phone: 425-917-
6595; fax: 425-917-6590; 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-2016-5042; 
Directorate Identifier 2015-NM-140-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

    Structural fatigue damage is progressive. It begins as minute 
cracks, and those cracks grow under the action of repeated stresses. 
This can happen because of normal operational conditions and design 
attributes, or because of isolated situations or incidents such as 
material defects, poor fabrication quality, or corrosion pits, dings, 
or scratches. Fatigue damage can occur locally, in small areas or 
structural design details, or globally. Global fatigue damage is 
general degradation of large areas of structure with similar structural 
details and stress levels. Multiple-site damage is global damage that 
occurs in a large structural element such as a single rivet line of a 
lap splice joining two large skin panels. Global damage can also occur 
in multiple elements such as adjacent frames or stringers. Multiple-
site-damage and multiple-element-damage cracks are typically too small 
initially to be reliably detected with normal inspection methods. 
Without intervention, these cracks will grow, and eventually compromise 
the structural integrity of the airplane, in a condition known as WFD. 
As an airplane ages, WFD will likely occur, and will certainly occur if 
the airplane is operated long enough without any intervention.
    The FAA's WFD final rule (75 FR 69746, November 15, 2010) became 
effective on January 14, 2011. The WFD rule requires certain actions to 
prevent structural failure due to WFD throughout the operational life 
of certain existing transport category airplanes and all of these 
airplanes that will be certificated in the future. For existing and 
future airplanes subject to the WFD rule, the rule requires that DAHs 
establish a limit of validity (LOV) of the engineering data that 
support the structural maintenance program. Operators affected by the 
WFD rule may not fly an airplane beyond its LOV, unless an extended LOV 
is approved.
    The WFD rule (75 FR 69746, November 15, 2010) does not require 
identifying and developing maintenance actions if the DAHs can show 
that such actions are not necessary to prevent WFD before the airplane 
reaches the LOV. Many LOVs, however, do depend on accomplishment of 
future maintenance actions. As stated in the WFD rule, any maintenance 
actions necessary to reach the LOV will be mandated by airworthiness 
directives through separate rulemaking actions.
    In the context of WFD, this action is necessary to enable DAHs to 
propose LOVs that allow operators the longest operational lives for 
their airplanes, and still ensure that WFD will not occur. This 
approach allows for an implementation strategy that provides 
flexibility to DAHs in determining the timing of service information 
development (with FAA approval), while providing operators with 
certainty

[[Page 19513]]

regarding the LOV applicable to their airplanes.
    The FAA has received a report indicating that an evaluation by the 
DAH has indicated that certain fastener locations in the window corner 
surround structure are subject to WFD. Fatigue cracking around certain 
fastener locations could cause multiple window corner skin cracks, 
which could result in rapid decompression and consequent reduced 
structural integrity of the airplane.

Related Service Information Under 1 CFR Part 51

    We reviewed Boeing Alert Service Bulletin 737-53A1351, dated July 
8, 2015. The service information describes procedures for HFEC 
inspections for cracking in certain fastener locations in the window 
corner surround structure and repair. 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 identified previously, except as discussed 
under ``Difference 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-2016-5042.

Difference Between This Proposed AD and the Service Information

    Boeing Alert Service Bulletin 737-53A1351, dated July 8, 2015, 
specifies to contact the manufacturer for instructions on how to repair 
certain conditions, but this proposed AD would require repairing those 
conditions 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 1,528 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......................  38 work-hours x     $0 [per inspection  $3,230 [per         $4,935,440 [per
                                   $85 per hour =      cycle].             inspection cycle].  inspection
                                   $3,230 [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 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-2016-5042; Directorate Identifier 
2015-NM-140-AD.

(a) Comments Due Date

    We must receive comments by May 20, 2016.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to all The Boeing Company Model 737-600, -700, -
700C, -800, -900 and -900ER series airplanes, certificated in any 
category.

(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 (DAH) indicating that certain fastener locations in the 
window corner surround structure are subject to

[[Page 19514]]

widespread fatigue damage (WFD). We are issuing this AD to detect 
and correct fatigue cracking around certain fastener locations that 
could cause multiple window corner skin cracks, which could result 
in rapid decompression and consequent reduced structural integrity 
of the airplane.

(f) Compliance

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

(g) Repetitive Inspections and Repair

    At the applicable time specified in paragraph 1.E., 
``Compliance,'' of Boeing Alert Service Bulletin 737-53A1351, dated 
July 8, 2015: Do an external high frequency eddy current (HFEC) 
inspection for cracking of the skin around the fastener locations at 
the upper forward and lower aft corners of each window between 
station (STA) 360 and STA 540, as applicable, and at the lower 
forward and upper aft corners of each window between STA 727 and STA 
887, in accordance with the Accomplishment Instructions of Boeing 
Alert Service Bulletin 737-53A1351, dated July 8, 2015. Repeat the 
inspection thereafter at the applicable times specified in paragraph 
1.E., ``Compliance,'' of Boeing Alert Service Bulletin 737-53A1351, 
dated July 8, 2015. If any crack is found during any inspection, 
repair before further flight using a method approved in accordance 
with the procedures specified in paragraph (i) of this AD.

(h) Exception to the Service Bulletin Specifications

    Although Boeing Alert Service Bulletin 737-53A1351, dated July 
8, 2015, specifies to contact Boeing for repair instructions, and 
specifies that action as ``RC'' (Required for Compliance), this AD 
requires repair before further flight 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, Seattle 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 (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, Seattle 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 (h) 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. 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 Jason 
Deutschman, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, 
Seattle ACO, 1601 Lind Avenue SW., Renton, WA 98057-3356; phone: 
425-917-6595; fax: 425-917-6590; email: [email protected].
    (2) 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. You may view the 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 March 24, 2016.
Michael Kaszycki,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2016-07577 Filed 4-4-16; 8:45 am]
BILLING CODE 4910-13-P