[Federal Register Volume 86, Number 67 (Friday, April 9, 2021)]
[Proposed Rules]
[Pages 18482-18484]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-07326]



[[Page 18482]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0262; Project Identifier AD-2020-00815-T]
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: The FAA proposes to adopt a new airworthiness directive (AD) 
for all The Boeing Company Model 757-200, -200PF, -200CB, and -300 
series airplanes. This proposed AD was prompted by crack indications 
found in the lower aft wing skin bolt holes where the flap tracks 
attach to the track support fitting. This proposed AD would require 
repetitive high frequency eddy current (HFEC) inspections for cracking 
of the lower aft wing skin aft edge at certain flap tracks, and repair 
if necessary. The FAA is proposing this AD to address the unsafe 
condition on these products.

DATES: The FAA must receive comments on this proposed AD by May 24, 
2021.

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 https://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 Boeing 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. For 
Aviation Partners Boeing service information identified in this NPRM, 
contact Aviation Partners Boeing, 2811 S 102nd Street, Suite 200, 
Seattle, WA 98168; telephone: 206-830-7699; internet: https://www.aviationpartnersboeing.com. You may view this referenced service 
information at the FAA, Airworthiness Products Section, Operational 
Safety Branch, 2200 South 216th St., Des Moines, WA. For information on 
the availability of this material at the FAA, call 206-231-3195. Boeing 
Alert Requirements Bulletin 757-57A0074 RB, dated June 11, 2020, is 
also available on the internet at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2021-0262.

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2021-0262; or in person at 
Docket Operations between 9 a.m. and 5 p.m., Monday through Friday, 
except Federal holidays. The AD docket contains this NPRM, any comments 
received, and other information. The street address for Docket 
Operations is listed above.

FOR FURTHER INFORMATION CONTACT: David Truong, Aerospace Engineer, 
Airframe Section, FAA, Los Angeles ACO Branch, 3960 Paramount 
Boulevard, Lakewood, CA 90712-4137; phone: 562-627-5224; fax: 562-627-
5210; email: [email protected].

SUPPLEMENTARY INFORMATION:

Comments Invited

    The FAA invites you to send any written relevant data, views, or 
arguments about this proposal. Send your comments to an address listed 
under ADDRESSES. Include ``Docket No. FAA-2021-0262; Project Identifier 
AD-2020-00815-T'' at the beginning of your comments. The most helpful 
comments reference a specific portion of the proposal, explain the 
reason for any recommended change, and include supporting data. The FAA 
will consider all comments received by the closing date and may amend 
this proposal because of those comments.
    Except for Confidential Business Information (CBI) as described in 
the following paragraph, and other information as described in 14 CFR 
11.35, the FAA will post all comments received, without change, to 
https://www.regulations.gov, including any personal information you 
provide. The agency will also post a report summarizing each 
substantive verbal contact received about this NPRM.

Confidential Business Information

    CBI is commercial or financial information that is both customarily 
and actually treated as private by its owner. Under the Freedom of 
Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public 
disclosure. If your comments responsive to this NPRM contain commercial 
or financial information that is customarily treated as private, that 
you actually treat as private, and that is relevant or responsive to 
this NPRM, it is important that you clearly designate the submitted 
comments as CBI. Please mark each page of your submission containing 
CBI as ``PROPIN.'' The FAA will treat such marked submissions as 
confidential under the FOIA, and they will not be placed in the public 
docket of this NPRM. Submissions containing CBI should be sent to David 
Truong, Aerospace Engineer, Airframe Section, FAA, Los Angeles ACO 
Branch, 3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 562-
627-5224; fax: 562-627-5210; email: [email protected]. Any 
commentary that the FAA receives which is not specifically designated 
as CBI will be placed in the public docket for this rulemaking.

Background

    The FAA has received a report indicating that, during teardown of a 
737-300 airplane, crack indications were found in the lower aft wing 
skin bolt holes where the flap tracks attach to the track support 
fitting at flap track numbers 1, 2, and 3. A metallurgical lab 
confirmed there were cracks at flap track numbers 2 and 3. The 
indication at flap track number 1 was confirmed by a metallurgical lab 
to have corrosion in the hole of the track support fitting, but no 
cracking in the skin. This damage is the result of local stresses being 
higher than expected. The left and right wing, lower aft wing skin pad-
up length is insufficient to reduce stress. The crack finding occurred 
at 67,695 flight cycles and 80,269 flight hours. Model 757 airplanes 
are of a similar design, with flap track attachment to the wing rear 
spar through skin overhang and track support fittings, for flap track 
number 2 (wing buttock line (WBL) 361) and flap track number 7 (WBL 
361). Undetected cracking in the lower aft wing skin, if not addressed, 
could result in the inability of the structure to carry limit load and 
could adversely affect the structural integrity of the airplane.

FAA's Determination

    The FAA is issuing this NPRM after determining that the unsafe 
condition described previously is likely to exist or develop on other 
products of the same type design.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Boeing Alert Requirements Bulletin 757-57A0074 RB, 
dated June 11, 2020, and Aviation Partner Boeing Alert Service Bulletin

[[Page 18483]]

AP757-57-011, dated August 21, 2020. This service information specifies 
procedures for repetitive HFEC inspections for cracking of the lower 
aft wing skin aft edge at flap track numbers 2 and 7 attachment 
locations, and repair. These documents are distinct since they apply to 
different airplane models in different configurations.
    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 ADDRESSES.

Proposed AD Requirements in This NPRM

    This proposed AD would require accomplishing the actions specified 
in the service information already described, except for any 
differences identified as exceptions in the regulatory text of this 
proposed AD. For information on the procedures and compliance times, 
see Boeing Alert Requirements Bulletin 757-57A0074 RB, dated June 11, 
2020, at https://www.regulations.gov by searching for and locating 
Docket No. FAA-2021-0262.

Explanation of Requirements Bulletin

    The FAA worked in conjunction with industry, under the 
Airworthiness Directive Implementation Aviation Rulemaking Committee 
(AD ARC), to enhance the AD system. One enhancement is a process for 
annotating which steps in the service information are ``required for 
compliance'' (RC) with an AD. Boeing has implemented this RC concept 
into Boeing service bulletins.
    In an effort to further improve the quality of ADs and AD-related 
Boeing service information, a joint process improvement initiative was 
worked between the FAA and Boeing. The initiative resulted in the 
development of a new process in which the service information more 
clearly identifies the actions needed to address the unsafe condition 
in the ``Accomplishment Instructions.'' The new process results in a 
Boeing Requirements Bulletin, which contains only the actions needed to 
address the unsafe condition (i.e., only the RC actions).

Costs of Compliance

    The FAA estimates that this proposed AD affects 483 airplanes of 
U.S. registry. The FAA estimates the following costs to comply with 
this proposed AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                 Cost on U.S.
             Action                     Labor cost          Parts cost     Cost per product        operators
----------------------------------------------------------------------------------------------------------------
Repetitive inspections.........  2 work-hours x $85 per               $0  $170 per            $82,110 per
                                  hour = $170 per                          inspection cycle.   inspection cycle.
                                  inspection cycle.
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    The FAA has received no definitive data on which to base the cost 
estimates for the on-condition repairs 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.
    The FAA is 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

    The FAA 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) Would not affect intrastate aviation in Alaska, and
    (3) Would 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:

The Boeing Company: Docket No. FAA-2021-0262; Project Identifier AD-
2020-00815-T.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by May 24, 2021.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to all The Boeing Company Model 757-200, -200PF, 
-200CB, and -300 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 crack indications found in the lower aft 
wing skin bolt holes where the flap tracks attach to the track 
support fitting. The FAA is issuing this AD to address undetected 
cracking in the lower aft wing skin, which could result in the 
inability of the structure to carry limit load and 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 all airplanes except those identified in paragraph 
(g)(2) of this AD: Except as specified by paragraph (h) of this AD, 
at the applicable times specified in the ``Compliance'' paragraph of 
Boeing Alert Requirements Bulletin 757-57A0074 RB, dated June 11, 
2020, do all applicable actions identified in, and in accordance 
with, the Accomplishment Instructions of Boeing Alert

[[Page 18484]]

Requirements Bulletin 757-57A0074 RB, dated June 11, 2020.

    Note 1 to paragraph (g): Guidance for accomplishing the actions 
required by this AD can be found in Boeing Alert Service Bulletin 
757-57A0074, dated June 11, 2020, which is referred to in Boeing 
Alert Requirements Bulletin 757-57A0074 RB, dated June 11, 2020.

    (2) For airplanes on which Aviation Partners Boeing blended 
winglets or scimitar blended winglets are installed using 
supplemental type certificate (STC) ST01518SE: Except as specified 
by paragraph (h) of this AD, at the applicable times specified in 
paragraph 1.E., ``Compliance'' of Aviation Partner Boeing Alert 
Service Bulletin AP757-57-011, dated August 21, 2020, do all 
applicable actions identified as ``RC'' (required for compliance) 
in, and in accordance with, the Accomplishment Instructions of 
Aviation Partner Boeing Alert Service Bulletin AP757-57-011, dated 
August 21, 2020.

(h) Exceptions to Service Information Specifications

    (1) Where Boeing Alert Requirements Bulletin 757-57A0074 RB, 
dated June 11, 2020, uses the phrase ``the original issue date of 
Requirements Bulletin 757-57A0074 RB,'' this AD requires using ``the 
effective date of this AD.''
    (2) Where Boeing Alert Requirements Bulletin 757-57A0074 RB, 
dated June 11, 2020, specifies contacting Boeing for repair 
instructions: This AD requires doing the repair before further 
flight using a method approved in accordance with the procedures 
specified in paragraph (i) of this AD.
    (3) Where Aviation Partner Boeing Alert Service Bulletin AP757-
57-011, dated August 21, 2020, uses the phrase ``the original issue 
date of this service bulletin,'' this AD requires using ``the 
effective date of this AD.''
    (4) Where Aviation Partner Boeing Alert Service Bulletin AP757-
57-011, dated August 21, 2020, specifies contacting Boeing for 
repair instructions: This AD requires doing the 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, 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 responsible Flight Standards 
Office, as appropriate. If sending information directly to the 
manager of the certification office, send it to the attention of the 
person identified in Related Information. 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 responsible Flight Standards 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 Company Organization Designation 
Authorization (ODA) that has been authorized by the Manager, Los 
Angeles ACO Branch, FAA, 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.

(j) Related Information

    (1) For more information about this AD, contact David Truong, 
Aerospace Engineer, Airframe Section, FAA, Los Angeles ACO Branch, 
3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 562-627-
5224; fax: 562-627-5210; email: [email protected].
    (2) For Boeing 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.
    (3) For Aviation Partners Boeing service information identified 
in this AD, contact Aviation Partners Boeing, 2811 S 102nd Street, 
Suite 200, Seattle, WA 98168; telephone: 206-830-7699; internet: 
https://www.aviationpartnersboeing.com.
    (4) You may view this referenced service information at the FAA, 
Airworthiness Products Section, Operational Safety Branch, 2200 
South 216th St., Des Moines, WA. For information on the availability 
of this material at the FAA, call 206-231-3195.

    Issued on March 30, 2021.
Ross Landes,
Deputy Director for Regulatory Operations, Compliance & Airworthiness 
Division, Aircraft Certification Service.
[FR Doc. 2021-07326 Filed 4-8-21; 8:45 am]
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