[Federal Register Volume 86, Number 119 (Thursday, June 24, 2021)]
[Rules and Regulations]
[Pages 33101-33103]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-13122]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0026; Project Identifier AD-2020-01164-T; 
Amendment 39-21544; AD 2021-10-11]
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 737-100, -200, -200C, -300, -400, and -500 
series airplanes. This AD was prompted by a report indicating that a 
crack was found on the splice angle flange that is attached to the 
station (STA) 540 bulkhead in the area between certain stringers. This 
AD requires repetitive surface high frequency eddy current (HFEC) 
inspections at the radius of the left- and right-side of the STA 540 
bulkhead splice angle for any 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 July 29, 2021.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of July 29, 
2021.

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-2021-0026.

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2021-0026; 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: 
Wayne.Ha@faa.gov.

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 February 24, 2021 (86 FR 
11186). The NPRM was prompted by a report indicating that a crack was 
found on the splice angle flange that is attached to the STA 540 
bulkhead in the area between certain stringers. In the NPRM, the FAA 
proposed to require repetitive surface HFEC inspections at the radius 
of the left- and right-side of the STA 540 bulkhead splice angle for 
any cracking, and applicable on-condition actions. The FAA is issuing 
this AD to address any cracking in the splice angle, which could result 
in the inability of a principal structural element to sustain limit 
load and could adversely affect the structural integrity of the 
airplane; in addition, such cracking could lead to

[[Page 33102]]

adjoining parts cracking and a potential fuel leak and consequent fire.

Discussion of Final Airworthiness Directive

Comments

    The FAA received a comment from Boeing who supported the NPRM 
without change.
    The FAA also received an additional comment from Aviation Partners 
Boeing.

Effect of Winglets on Accomplishment of the Proposed Actions

    Aviation Partners Boeing stated that accomplishing Supplemental 
Type Certificate (STC) ST01219SE does not affect the actions specified 
in the proposed AD.
    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.

Conclusion

    The FAA reviewed the relevant data, considered any comments 
received, and determined that air safety requires adopting this AD as 
proposed. Accordingly, the FAA is issuing this AD to address the unsafe 
condition on these products. 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 737-57A1347 RB, 
dated July 29, 2020. The service information describes procedures for 
repetitive surface HFEC inspections at the radius of the left- and 
right-side of the STA 540 bulkhead splice angle for any cracking, and 
applicable on-condition actions. On-condition actions include 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 117 airplanes of U.S. 
registry. The FAA estimates the following costs to comply with this AD:

                                      Estimated Costs for Required Actions
----------------------------------------------------------------------------------------------------------------
                                                                                                 Cost on U.S.
              Action                    Labor cost        Parts cost      Cost per product        operators
----------------------------------------------------------------------------------------------------------------
Repetitive surface HFEC            7 work-hour x $85                $0  $595 per inspection  $69,615 per
 inspections.                       per hour = $595                      cycle.               inspection cycle.
                                    per inspection
                                    cycle.
----------------------------------------------------------------------------------------------------------------

    The FAA estimates the following costs to do any necessary on-
condition actions that would be required. The FAA has no way of 
determining the number of aircraft that might need these on-condition 
actions:

                 Estimated Costs of On-Condition Actions
------------------------------------------------------------------------
          Labor cost                  Parts cost        Cost per product
------------------------------------------------------------------------
Up to 53 work-hour x $85 per   Up to $1,000...........  Up to $5,505.
 hour = Up to $4,505
 (replacement).
------------------------------------------------------------------------

    The FAA has received no definitive data on which to base the cost 
estimates for the on-condition repair 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.

[[Page 33103]]

Sec.  39.13  [Amended]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive:

2021-10-11 The Boeing Company: Amendment 39-21544; Docket No. FAA-
2021-0026 Project Identifier AD-2020-01164-T.

(a) Effective Date

    This airworthiness directive (AD) is effective July 29, 2021.

(b) Affected ADs

    None.

(c) Applicability

    (1) This AD applies to all The Boeing Company Model 737-100, -
200, -200C, -300, -400, and -500 series airplanes, certificated in 
any category.
    (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 57, Wings.

(e) Unsafe Condition

    This AD was prompted by a report indicating that a crack was 
found on the splice angle flange that is attached to the station 
(STA) 540 bulkhead in the area between stringer 21 to stringer 22. 
The FAA is issuing this AD to address any cracking in the splice 
angle, which could result in the inability of a principal structural 
element to sustain limit load and could adversely affect the 
structural integrity of the airplane; in addition, such cracking 
could lead to adjoining parts cracking and a potential fuel leak and 
consequent fire.

(f) Compliance

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

(g) Required Actions

    (1) For airplanes identified as Group 1 in Boeing Alert 
Requirements Bulletin 737-57A1347 RB, dated July 29, 2020: Within 
120 days after the effective date of this AD, inspect the airplane 
and do all applicable on-condition actions using a method approved 
in accordance with the procedures specified in paragraph (i) of this 
AD.
    (2) For airplanes identified as Group 2 in Boeing Alert 
Requirements Bulletin 737-57A1347 RB, dated July 29, 2020: Except as 
specified by paragraph (h) of this AD, at the applicable times 
specified in the ``Compliance'' paragraph of Boeing Alert 
Requirements Bulletin 737-57A1347 RB, dated July 29, 2020, do all 
applicable actions identified in, and in accordance with, the 
Accomplishment Instructions of Boeing Alert Requirements Bulletin 
737-57A1347 RB, dated July 29, 2020.
    Note 1 to paragraph (g): Guidance for accomplishing the actions 
required by this AD can be found in Boeing Alert Service Bulletin 
737-57A1347, dated July 29, 2020, which is referred to in Boeing 
Alert Requirements Bulletin 737-57A1347 RB, dated July 29, 2020.

(h) Exceptions to Service Information Specifications

    (1) Where Boeing Alert Requirements Bulletin 737-57A1347 RB, 
dated July 29, 2020, uses the phrase ``the original issue date of 
Requirements Bulletin 737-57A1347 RB,'' this AD requires using ``the 
effective date of this AD.''
    (2) Where Boeing Alert Requirements Bulletin 737-57A1347 RB, 
dated July 29, 2020, specifies contacting Boeing for repair 
instructions: This AD requires doing the repair 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 paragraph (j)(1) of this AD. Information may be 
emailed to: 9-ANM-LAACO-AMOC-Requests@faa.gov.
    (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: Wayne.Ha@faa.gov.
    (2) Service information identified in this AD that is not 
incorporated by reference is available at the addresses specified in 
paragraphs (k)(3) and (4) 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 737-57A1347 RB, dated 
July 29, 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 fedreg.legal@nara.gov, or go to: https://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued on April 30, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-13122 Filed 6-23-21; 8:45 am]
BILLING CODE 4910-13-P


