[Federal Register Volume 87, Number 11 (Tuesday, January 18, 2022)]
[Rules and Regulations]
[Pages 2534-2536]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-00584]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0609; Project Identifier AD-2021-00274-T; 
Amendment 39-21861; AD 2021-26-03]
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 
certain The Boeing Company Model 737-300, -400, and -500 series 
airplanes. This AD was prompted by an evaluation by the design approval 
holder (DAH) indicating that the frame splice between certain stringers 
is subject to widespread fatigue damage (WFD). This AD requires an 
inspection of certain fuselage frame splices for existing repairs, 
repetitive inspections of certain fuselage frame splices for cracking, 
and applicable on-condition actions. The FAA is issuing this AD to 
address the unsafe condition on these products.

DATES: This AD is effective February 22, 2022.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of February 22, 
2022.

ADDRESSES: For 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. 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-2021-0609.

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2021-0609; 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 certain The Boeing 
Company Model 737-300, -400, and -500 series airplanes. The NPRM 
published in the Federal Register on August 24, 2021 (86 FR 47255). The 
NPRM was prompted by an evaluation by the DAH indicating that the frame 
splice between certain stringers is subject to WFD. In the NPRM, the 
FAA proposed to require an inspection of certain fuselage frame splices 
for existing repairs, repetitive inspections of certain fuselage frame 
splices for cracking, and applicable on-condition actions. The FAA is 
issuing this AD to address upper frame cracking common to the frame 
splice between stringer S-13 and S-14, which could interact with 
stringer S-14 skin lap splice lower fastener row cracking in lower skin 
and result in an uncontrolled decompression of the airplane and loss of 
structural integrity.

[[Page 2535]]

Discussion of Final Airworthiness Directive

Comments

    The FAA received comments from Aviation Partners Boeing and Boeing. 
The following presents the comments received on the NPRM and the FAA's 
response to each comment.

Effect of Winglets on Accomplishment of the Proposed Actions

    Aviation Partners Boeing stated that the installation of winglets 
per Supplemental Type Certificate STC ST01219SE does not affect the 
accomplishment of the manufacturer's service instructions.
    The FAA concurs with the commenter. The FAA has redesignated 
paragraph (c) of the proposed AD as paragraph (c)(1) of this AD and 
added paragraph (c)(2) to this AD to state that installation of STC 
ST01219SE does not affect the ability to accomplish the actions 
required by this AD. Therefore, for airplanes on which STC ST01219SE is 
installed, a ``change in product'' alternative method of compliance 
(AMOC) approval request is not necessary to comply with the 
requirements of 14 CFR 39.17.

Request To Add Inspection Method

    Boeing requested that the words ``high frequency eddy current 
(HFEC)'' be added to the sentence that describes the repetitive 
inspections in the ``Related Service Information under 1 CFR part 51'' 
section of the proposed AD. Boeing stated that the HFEC inspection 
should be mentioned because that is the inspection that mitigates the 
unsafe condition.
    The FAA agrees with the request. The requested wording has been 
added to the specified section of this final rule.

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 increase the economic burden on any operator.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Boeing Alert Requirements Bulletin 737-53A1388 RB, 
dated October 27, 2020. This service information specifies procedures 
for a general visual inspection (GVI) of the fuselage frame splices 
between stringer S-13 and S-14 station (STA) 360 to STA 520 and STA 
727A to STA 907 for existing repairs, repetitive high frequency eddy 
current (HFEC) inspections of the fuselage frame splices between 
stringer S-13 and S-14 from STA 360 to STA 520 and STA 727A to STA 907 
for cracking, and applicable on-condition actions. On-condition actions 
include an open hole HFEC inspection for cracking at all fastener hole 
locations where a fastener was removed due to finding a cracked 
doubler, repair, or replacement. 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 66 airplanes of U.S. 
registry. The FAA estimates the following costs to comply with this AD:

                                                                     Estimated Costs
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                                                                 Parts
               Action                        Labor cost           cost               Cost per product                     Cost on U.S. operators
--------------------------------------------------------------------------------------------------------------------------------------------------------
Repetitive Inspections..............  Up to 267 work-hours x          $0  Up to $22,695 per inspection cycle....  Up to $1,497,870 per inspection cycle.
                                       $85 per hour = Up to
                                       $22,695 per inspection
                                       cycle.
GVI.................................  2 work-hours x $85 per           0  $170..................................  $11,220.
                                       hour = $170.
--------------------------------------------------------------------------------------------------------------------------------------------------------

    The FAA has received no definitive data on which to base the 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:

2021-26-03 The Boeing Company: Amendment 39-21861; Docket No. FAA-
2021-0609; Project Identifier AD-2021-00274-T.

[[Page 2536]]

(a) Effective Date

    This airworthiness directive (AD) is effective February 22, 
2022.

(b) Affected ADs

    None.

(c) Applicability

    (1) This AD applies to The Boeing Company Model 737-300, -400, 
and -500 series airplanes, certificated in any category, as 
identified in Boeing Alert Requirements Bulletin 737-53A1388 RB, 
dated October 27, 2020.
    (2) Installation of Supplemental Type Certificate (STC) 
ST01219SE does not affect the ability to accomplish the actions 
required by this AD. Therefore, for airplanes on which STC ST01219SE 
is installed, a ``change in product'' alternative method of 
compliance (AMOC) approval request is not necessary to comply with 
the requirements of 14 CFR 39.17.

(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 the frame splice between stringer S-13 
and S-14 is subject to widespread fatigue damage (WFD). The FAA is 
issuing this AD to address upper frame cracking common to the frame 
splice between stringer S-13 and S-14, which could interact with 
stringer S-14 skin lap splice lower fastener row cracking in lower 
skin and result in an uncontrolled decompression of the airplane and 
loss of structural integrity.

(f) Compliance

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

(g) Required Actions

    Except as specified by paragraph (h) of this AD: At the 
applicable times specified in the ``Compliance'' paragraph of Boeing 
Alert Requirements Bulletin 737-53A1388 RB, dated October 27, 2020, 
do all applicable actions identified in, and in accordance with, the 
Accomplishment Instructions of Boeing Alert Requirements Bulletin 
737-53A1388 RB, dated October 27, 2020.
    Note 1 to paragraph (g): Guidance for accomplishing the actions 
required by this AD can be found in Boeing Alert Service Bulletin 
737-53A1388, dated October 27, 2020, which is referred to in Boeing 
Alert Requirements Bulletin 737-53A1388 RB, dated October 27, 2020.

(h) Exceptions to Service Information Specifications

    (1) Where Boeing Alert Requirements Bulletin 737-53A1388 RB, 
dated October 27, 2020, uses the phrase ``the Original Issue date of 
Requirements Bulletin 737-53A1388 RB,'' this AD requires using ``the 
effective date of this AD,'' except where Alert Requirements 
Bulletin 737-53A1388 RB, dated October 27, 2020, uses the phrase 
``the Original Issue date of Requirements Bulletin 737-53A1388 RB,'' 
in a note or flag note.
    (2) Where Boeing Alert Requirements Bulletin 737-53A1388 RB, 
dated October 27, 2020, specifies contacting Boeing for repair 
instructions or for alternative inspections: This AD requires doing 
the repair, or doing the alternative inspections and applicable on-
condition actions 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 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].

(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 737-53A1388 RB, dated 
October 27, 2020.
    (ii) [Reserved]
    (3) 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.
    (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 December 8, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2022-00584 Filed 1-14-22; 8:45 am]
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