Document ID: FAA-2021-0262-0009
Agency: faa
Document Type: Rule
Title: Airworthiness Directives: The Boeing Company Airplanes
Posted Date: 2021-11-24T05:00Z

[Federal Register Volume 86, Number 224 (Wednesday, November 24, 2021)]
[Rules and Regulations]
[Pages 66931-66934]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-25533]

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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; 
Amendment 39-21796; AD 2021-22-23]
RIN 2120-AA64

Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all 
The Boeing Company Model 757-200, -200PF, -200CB, and -300 series 
airplanes. 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; this finding was on a Model 737-300 series airplane, 
which has a design similar to the Model 757 airplanes. This AD requires 
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 issuing this AD to address the unsafe 
condition on these products.

DATES: This AD is effective December 29, 2021.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in this AD as of December 29, 
2021.

ADDRESSES: For Boeing service information identified in this final 
rule, 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 final rule, 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 
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. It is also available 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 final rule, any 
comments received, and other information. The address for Docket 
Operations is U.S. Department of Transportation, Docket Operations, M-
30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue 
SE, Washington, DC 20590.

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; email: 
[email protected].

SUPPLEMENTARY INFORMATION:

Background

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 by adding an AD that would apply to all The Boeing Company 
Model 757-200, -200PF, -200CB, and -300 series airplanes. The NPRM 
published in the Federal Register on April 9, 2021 (86 FR 18482). The 
NPRM was prompted by crack indications found in the lower aft wing skin 
bolt holes where the flap tracks attach to the track support fitting. 
In the NPRM, the FAA proposed to require repetitive HFEC inspections 
for cracking of the lower aft wing skin aft edge at certain flap 
tracks, and repair if necessary. 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.

[[Page 66932]]

Discussion of Final Airworthiness Directive

Comments

    The FAA received comments from five commenters, including Aviation 
Partners Boeing, Delta Air Lines, United Airlines, FedEx, and Boeing. 
The following presents the comments received on the NPRM and the FAA's 
response to each comment.

Request for Correction of Typographical Error

    Aviation Partners Boeing (APB) and Delta Air Lines (DAL) requested 
that references to ``Aviation Partner Boeing'' at several places in the 
proposed AD be corrected to ``Aviation Partners Boeing.'' APB noted 
that this typographical error appeared in paragraphs (g)(2), (h)(3), 
and (h)(4) of the proposed AD. DAL also noted the typographical error 
in the ``Related Service Information Under 1 CFR Part 51'' section of 
the proposed AD.
    The FAA acknowledges the error and has corrected those references 
in this AD at the places noted.

Request for Revision of Required Actions Paragraph

    DAL requested that the qualifying statement of paragraph (g)(2) of 
the proposed AD be revised or greater clarity added to paragraphs 
(g)(1) and (2) of the proposed AD regarding the status of aircraft 
modified in accordance with Aviation Partners Boeing Service Bulletin 
AP757-57-001, Revision 1, dated May 18, 2012, which removes winglets 
installed per supplemental type certificate (STC) ST01518SE. DAL stated 
that, because the compliance times for aircraft affected by Aviation 
Partners Boeing Alert Service Bulletin AP757-57-011, dated August 21, 
2020, are shortened and additional inspection areas included, it is 
unlikely that accomplishment of Aviation Partners Boeing Service 
Bulletin AP757-57-001, Revision 1, dated May 18, 2012, would restore 
the aircraft to a configuration that could use the inspection times and 
locations defined in paragraph (g)(1) of the proposed AD, even though 
they would no longer be regarded as having blended winglets or scimitar 
blended winglets installed.
    The FAA agrees with the request to revise the qualifying statement 
of paragraph (g)(2) of this AD. For aircraft modified in accordance 
with STC ST01518SE that subsequently have the STC winglets removed by 
Aviation Partners Boeing Service Bulletin AP757-57-001, Revision 1, 
dated May 18, 2012, the wing modification does not get removed, 
therefore Aviation Partners Boeing Alert Service Bulletin AP757-57-011, 
dated August 21, 2020, would still be applicable. The qualifying 
statement of paragraph (g)(2) of this AD has been changed to read, 
``For airplanes on which Aviation Partners Boeing blended winglets or 
scimitar blended winglets are installed using STC ST01518SE, or on 
which such winglets have been installed and subsequently removed.''

Request To Clarify Source of Findings

    Boeing requested that the Summary and paragraph (e) of the proposed 
AD be rewritten to clarify that the unsafe condition prompting the 
proposed AD was not discovered on a Model 757 airplane. The commenter 
stated that the subject sentence may be misleading as is. Boeing noted 
that crack indications were found in a Model 737-300 airplane, which 
has a similar configuration to the Model 757 airplane in this area, but 
there are no reports of cracking in the area for a Model 757 airplane.
    The FAA agrees with the request to clarify. The suggested 
clarification has been added to the Summary and paragraph (e) of this 
AD.

Request To Confirm Inspection Effectiveness

    FedEx requested confirmation that the HFEC inspection described in 
Boeing Alert Service Bulletin 757-57A0074, dated June 11, 2020, will be 
sufficient to detect the described unsafe condition. FedEx noted that 
the proposed AD is based on a crack originating from a fastener hole. 
FedEx stated that, due to the relatively low depth penetration of HFEC, 
the inspection specified in the service information will not likely 
detect a crack until it has propagated through to the free edge of the 
lower aft wing skin.
    The FAA has determined that the HFEC inspection will be sufficient 
to detect the unsafe condition. This is a proactive AD for the 757 
fleet, based on a crack finding in a Model 737 airplane with a similar 
design. The unsafe condition exists when a fastener hole crack reaches 
the lower aft wing skin aft edge. Crack growth analysis has determined 
that the existing structural integrity of the Model 757 airplanes in 
this area is such that HFEC inspections at the intervals specified in 
the applicable service information would be able to detect a crack 
propagating from a fastener hole to the lower aft wing skin aft edge.

Request To Modify Proposed AD Requirements Paragraph

    Boeing requested that the APB service information be added to the 
``Proposed AD Requirements in This NPRM'' section of the NPRM. The 
commenter stated that the addition of the APB bulletin information in 
the statement would inform the reviewer of all applicable service 
information addressed by the proposed AD.
    The FAA agrees that APB service information should have been 
included in the referenced section of the NPRM. However, the referenced 
section does not appear in this final rule. This AD has not been 
changed with regard to this request.

Request To Clarify Intent of Note

    Boeing requested that ``Note 1 to paragraph (g)'' be changed to 
``Note 1 to paragraph (g)(1)'' because as worded it implies that the 
Boeing service bulletin gives additional guidance for the APB bulletin, 
but it only gives additional guidance for the specified Boeing 
requirements bulletin.
    The FAA agrees and has made the specified change.

Request To Modify Related Service Information Paragraph

    United Airlines, DAL, and Boeing asked that the Related Service 
Information under 1 CFR part 51 paragraph be clarified to include HFEC 
inspections at flap track numbers 1 and 8 for aircraft with blended 
winglets or scimitar blended winglets. The commenters stated that the 
APB service bulletin requires additional inspections other than those 
required in the Boeing requirements bulletin. DAL noted that if the 
intent is to not require inspections at flap track numbers 1 and 8, 
paragraph (h) of the proposed AD should be revised to clarify that 
intent.
    The FAA agrees with the request and notes that the intent is to 
require inspections at all flap track numbers specified in the 
applicable service information. The FAA has revised the ``Related 
Service Information Under 1 CFR Part 51'' section of this AD 
accordingly. The FAA has also revised the ``Costs of Compliance'' 
section to clarify the difference in work hours between the two 
bulletins.

Conclusion

    The FAA reviewed the relevant data, considered any comments 
received, and determined that air safety requires adopting this AD as 
proposed. Except for minor editorial changes, and any other changes 
described previously, this AD is adopted as proposed in the NPRM. None 
of the changes will

[[Page 66933]]

increase the economic burden on any operator.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Boeing Alert Requirements Bulletin 757-57A0074 RB, 
dated June 11, 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. 
The FAA also reviewed Aviation Partners Boeing Alert Service Bulletin 
AP757-57-011, dated August 21, 2020, which specifies procedures for 
repetitive HFEC inspections for cracking of the lower aft wing skin aft 
edge at flap track numbers 1, 2, 7, and 8 attachment locations, 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 ADDRESSES.

Costs of Compliance

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

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                 Cost on U.S.
              Action                    Labor cost        Parts cost      Cost per product        operators
----------------------------------------------------------------------------------------------------------------
Repetitive inspections (per        2 work-hours x $85               $0  $170 per inspection  Up to $82,110 per
 Boeing bulletin).                  per hour = $170                      cycle.               inspection cycle.
                                    per inspection
                                    cycle.
Repetitive inspections (per APB    3 work-hours x $85                0  $255 per inspection  Up to $123,165 per
 bulletin).                         per hour = $255                      cycle.               inspection cycle.
                                    per inspection
                                    cycle.
----------------------------------------------------------------------------------------------------------------

    The FAA has received no definitive data on which to base the cost 
estimates for the on-condition repairs specified in this 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

    This AD will not have federalism implications under Executive Order 
13132. This AD will 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 that this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Will not affect intrastate aviation in Alaska, and
    (3) 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 Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA amends 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:

2021-22-23 The Boeing Company: Amendment 39-21796; Docket No. FAA-
2021-0262; Project Identifier AD-2020-00815-T.

(a) Effective Date

    This airworthiness directive (AD) is effective December 29, 
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; this finding was on a Model 737-300 series 
airplane, which has a similar design to the Model 757 airplanes. 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 Requirements 
Bulletin 757-57A0074 RB, dated June 11, 2020.
    Note 1 to paragraph (g)(1): 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, or on which they have 
been installed and subsequently removed: Except as specified by 
paragraph (h) of this AD, at the applicable times specified in 
paragraph 1.E., ``Compliance'' of Aviation Partners 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

[[Page 66934]]

Partners 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 Partners 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 Partners 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

    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; email: [email protected].

(k) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do 
the actions required by this AD, unless the AD specifies otherwise.
    (i) Aviation Partners Boeing Alert Service Bulletin AP757-57-
011, dated August 21, 2020.
    (ii) Boeing Alert Requirements Bulletin 757-57A0074 RB, dated 
June 11, 2020.
    (3) 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. 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 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.
    (5) You may view this service information that is incorporated 
by reference at the National Archives and Records Administration 
(NARA). For information on the availability of this material at 
NARA, [email protected], or go to: https://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued on October 22, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-25533 Filed 11-23-21; 8:45 am]
BILLING CODE 4910-13-P