[Federal Register Volume 86, Number 77 (Friday, April 23, 2021)]
[Rules and Regulations]
[Pages 21635-21637]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-08508]



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 Rules and Regulations
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  Federal Register / Vol. 86, No. 77 / Friday, April 23, 2021 / Rules 
and Regulations  

[[Page 21635]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-0587; Product Identifier 2020-NM-086-AD; Amendment 
39-21506; AD 2021-08-12]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all 
The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 
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 AD requires repetitive inspections for 
cracking of the left and right wing, lower aft wing skin aft edge, at 
certain flap track locations, and applicable on-condition actions. The 
FAA is issuing this AD to address the unsafe condition on these 
products.

DATES: This AD is effective May 28, 2021.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in this AD as of May 28, 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 South 102nd St., 
Suite 200, Seattle, WA 98168; phone: 206-830-7699; fax: 206-767-0535; 
email: [email protected]; internet: http://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-2020-
0587.

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2020-0587; 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: Wayne Ha, Aerospace Engineer, Airframe 
Section, FAA, Los Angeles ACO Branch, 3960 Paramount Boulevard, 
Lakewood, CA 90712-4137; phone: 562-627-5238; fax: 562-627-5210; 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 737-100, -200, -200C, -300, -400, and -500 series airplanes. The 
NPRM published in the Federal Register on July 28, 2020 (85 FR 45355). 
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.
    The FAA issued a supplemental notice of proposed rulemaking (SNPRM) 
to amend 14 CFR part 39 by adding an AD that would apply to all The 
Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series 
airplanes. The SNPRM published in the Federal Register on January 21, 
2021 (86 FR 6276). The SNPRM was prompted by a determination that the 
compliance time should be reduced for airplanes on which Aviation 
Partners Boeing (APB) blended winglets have been installed using 
supplemental type certificate (STC) ST01219SE. The SNPRM proposed to 
require repetitive inspections for cracking of the left and right wing, 
lower aft wing skin aft edge, at certain flap track locations, and 
applicable on-condition actions. The FAA is issuing this AD to address 
undetected cracking in the lower wing skin, which could result in the 
inability of the structure to carry limit load, and adversely affect 
the structural integrity of the airplane.

Discussion of Final Airworthiness Directive

Comments

    The FAA received no comments on the SNPRM or on the determination 
of the cost to the public.

Conclusion

    The FAA reviewed the relevant data and determined that air safety 
requires adopting this AD as proposed. Except for minor editorial 
changes, this AD is adopted as proposed in the SNPRM. None of the 
changes will increase the economic burden on any operator.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Boeing Alert Requirements Bulletin 737-57A1349 RB, 
dated April 14, 2020, and Aviation Partners Boeing Alert Service 
Bulletin AP737C-57-003, dated July 28, 2020. The service information 
describes procedures for repetitive high frequency eddy current 
inspections for cracking of the left and right wing, lower aft wing 
skin aft edge, at flap track numbers 1, 2, 3, 6, 7, and 8 attachment 
location and applicable on-condition actions. On-condition actions 
include repairing any cracking found. 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 the ADDRESSES section.

Costs of Compliance

    The FAA estimates that this AD affects 141 airplanes of U.S. 
registry. The FAA estimates the following costs to comply with this AD:

[[Page 21636]]



                                      Estimated Costs for Required Actions
----------------------------------------------------------------------------------------------------------------
                                                                                                 Cost on U.S.
             Action                     Labor cost          Parts cost     Cost per product        operators
----------------------------------------------------------------------------------------------------------------
HFEC inspections...............  7 work-hours x $85 per               $0  $595 per            $83,895 per
                                  hour = $595 per                          inspection cycle.   inspection cycle.
                                  inspection cycle.
----------------------------------------------------------------------------------------------------------------

    The FAA has received no definitive data that would enable providing 
cost estimates for the on-condition actions 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:

2021-08-12 The Boeing Company: Amendment 39-21506; Docket No. FAA-
2020-0587; Product Identifier 2020-NM-086-AD.

(a) Effective Date

    This airworthiness directive (AD) is effective May 28, 2021.

(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 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 wing skin, which could result in the inability 
of the structure to carry limit load, and 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 in paragraph (h) of this AD, 
at the applicable times specified in the ``Compliance'' paragraph in 
Boeing Alert Requirements Bulletin 737-57A1349 RB, dated April 14, 
2020, do all applicable actions identified in, and in accordance 
with, the Accomplishment Instructions of Boeing Alert Requirements 
Bulletin 737-57A1349 RB, dated April 14, 2020.
    (2) For airplanes on which Aviation Partners Boeing blended 
winglets are installed using supplemental type certificate (STC) 
ST01219SE: Except as specified in paragraph (h) of this AD, at the 
applicable time in the ``Compliance'' paragraph in Aviation Partners 
Boeing Alert Service Bulletin AP737C-57-003, dated July 28, 2020, do 
all applicable actions identified in, and in accordance with, the 
Accomplishment Instructions of Boeing Alert Requirements Bulletin 
737-57A1349 RB, dated April 14, 2020.
    Note 1 to paragraph (g): Guidance for accomplishing the actions 
required by this AD can be found in Boeing Alert Service Bulletin 
737-57A1349, dated April 14, 2020, which is referred to in Boeing 
Alert Requirements Bulletin 737-57A1349 RB, dated April 14, 2020.

(h) Exceptions to Service Information Specifications

    (1) Where Boeing Alert Requirements Bulletin 737-57A1349 RB, 
dated April 14, 2020, uses the phrase ``the original issue date of 
Requirements Bulletin 737-57A1349 RB,'' this AD requires using ``the 
effective date of this AD.''
    (2) Where Boeing Alert Requirements Bulletin 737-57A1349 RB, 
dated April 14, 2020, specifies contacting Boeing for repair 
instructions: This AD requires doing the repair and applicable on-
condition actions before further flight using a method approved in 
accordance with the procedures specified in paragraph (i) of this 
AD.
    (3) For airplanes identified as Group 1 in Boeing Alert 
Requirements Bulletin 737-57A1349 RB, dated April 14, 2020: Within 
120 days after the effective date of this AD, do actions to correct 
the unsafe condition using a method approved in accordance with the 
procedures specified in paragraph (i) of this AD.
    (4) Where Aviation Partners Boeing Alert Service Bulletin 
AP737C-57-003, dated July 28, 2020, uses the phrase ``the original 
issue date of this service bulletin,'' this AD requires using ``the 
effective date of this AD.''
    (5) Where Aviation Partners Boeing Alert Service Bulletin 
AP737C-57-003, dated July 28, 2020, specifies contacting Boeing for 
repair instructions: This AD requires doing the repair and 
applicable on-condition actions 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 local Flight Standards 
District Office, as appropriate. If sending information directly to 
the manager of the certification office, send it to the attention of

[[Page 21637]]

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 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 Wayne Ha, 
Aerospace Engineer, Airframe Section, FAA, Los Angeles ACO Branch, 
3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 562-627-
5238; fax: 562-627-5210; email: [email protected].
    (2) Service information identified in this AD that is not 
incorporated by reference is available at the addresses specified in 
paragraphs (k)(3) and (5) of this AD.

(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) Boeing Alert Requirements Bulletin 737-57A1349 RB, dated 
April 14, 2020.
    (ii) Aviation Partners Boeing Alert Service Bulletin AP737C-57-
003, dated July 28, 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.
    (4) For Aviation Partners Boeing service information identified 
in this AD, contact Aviation Partners Boeing, 2811 South 102nd St., 
Suite 200, Seattle, WA 98168; phone: 206-830-7699; fax: 206-767-
0535; email: [email protected]; internet: http://www.aviationpartnersboeing.com.
    (5) 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.
    (6) 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 [email protected], or go to: https://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued on April 5, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-08508 Filed 4-22-21; 8:45 am]
BILLING CODE 4910-13-P