[Federal Register Volume 89, Number 10 (Tuesday, January 16, 2024)]
[Proposed Rules]
[Pages 2515-2517]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-00345]


 ========================================================================
 Proposed Rules
                                                 Federal Register
 ________________________________________________________________________
 
 This section of the FEDERAL REGISTER contains notices to the public of 
 the proposed issuance of rules and regulations. The purpose of these 
 notices is to give interested persons an opportunity to participate in 
 the rule making prior to the adoption of the final rules.
 
 ========================================================================
 

  Federal Register / Vol. 89, No. 10 / Tuesday, January 16, 2024 / 
Proposed Rules  

[[Page 2515]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2024-0028; Project Identifier AD-2023-00919-T]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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

SUMMARY: The FAA proposes to supersede Airworthiness Directive (AD) 
2021-09-06, which applies to all The Boeing Company Model 737-600, -
700, -700C, -800, -900, and -900ER series airplanes. AD 2021-09-06 
requires repetitive inspections for cracking of the left- and right-
hand side outboard chords of certain frame fittings and failsafe straps 
at a certain station around eight fasteners, and repair if any cracking 
is found. Since the FAA issued AD 2021-09-06, additional reports of 
cracking in the area were received and it was determined that 
additional inspections are needed to address the unsafe condition. This 
proposed AD would require repetitive detailed and ultrasonic 
inspections for cracking of the left-and right-hand sides of certain 
frame fittings and failsafe straps, and repair if any cracking is 
found. 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 March 1, 
2024.

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 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.
    AD Docket: You may examine the AD docket at regulations.gov under 
Docket No. FAA-2024-0028; 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.
    Material Incorporated by Reference:
     For 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; website 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 
regulations.gov by searching for and locating Docket No. FAA-2024-0028.

FOR FURTHER INFORMATION CONTACT: Owen Bley-Male, Aviation Safety 
Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; telephone 
206-231-3992; 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-2024-0028; Project Identifier 
AD-2023-00919-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 
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 Owen 
Bley-Male, Aviation Safety Engineer, FAA, 2200 South 216th St., Des 
Moines, WA 98198; telephone 206-231-3992; email [email protected]. Any commentary that the FAA receives that is not 
specifically designated as CBI will be placed in the public docket for 
this rulemaking.

Background

    The FAA issued AD 2021-09-06, Amendment 39-21519 (86 FR 23595, May 
4, 2021) (AD 2021-09-06), for all The Boeing Company Model 737-600, -
700, -700C, -800, -900, and -900ER series airplanes. AD 2021-09-06 was 
prompted by reports of cracking discovered in the station (STA) 663.75 
frame fitting outboard chords and failsafe straps adjacent to the 
stringer S-18A straps and a determination that the initial inspection 
threshold and repetitive inspection interval required by AD 2019-22-10, 
Amendment 39-19789 (84 FR 61533, November 13, 2019), were inadequate to 
address cracking in a timely manner. AD 2021-09-06 requires repetitive 
inspections for cracking of the left- and right-hand side outboard 
chords of frame fittings and failsafe straps at a certain station 
around eight fasteners, repair if any cracking is

[[Page 2516]]

found, and an inspection report. The agency issued AD 2021-09-06 to 
address cracking in the STA 663.75 frame fitting outboard chords and 
failsafe straps adjacent to the stringer S-18A straps, which could 
result in failure of a principal structural element (PSE) to sustain 
limit load. This condition could adversely affect the structural 
integrity of the airplane and result in loss of control of the 
airplane.

Actions Since AD 2021-09-06 Was Issued

    Since the FAA issued AD 2021-09-06, additional reports have been 
made of several cracks in the STA 663.75 frame fittings and failsafe 
straps. Cracks have also been found at the aft fastener common to the 
failsafe strap upper row. Several cracks in the frame fitting were 
found extending beyond the aft fastener hole to the forward fastener 
hole. An additional report was made of a visible crack in the failsafe 
strap without any visibly detectable crack in the frame fitting. These 
additional reports led to a determination that the detailed visual 
inspection required by AD 2021-09-06 might not be adequate to detect 
STA 663.75 failsafe strap cracking.
    Additionally, the preamble to AD 2021-09-06 explained that the FAA 
considered the requirements ``interim action'' and was considering 
further rulemaking. The FAA has now determined that further rulemaking 
is indeed necessary and this proposed AD follows from that 
determination.

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 737-53A1414 RB, 
Revision 1, dated November 20, 2023. This service information specifies 
procedures for repetitive internal detailed inspection for cracking of 
the frame fitting and visible areas of the failsafe strap at STA 663.73 
(left- and right-hand sides), repetitive external detailed and 
ultrasonic inspections for cracking of the failsafe strap at STA 663.75 
(left- and right-hand sides), and repair if any cracking is found. 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

    Although this proposed AD does not explicitly restate the 
requirements of AD 2021-09-06, this proposed AD would retain the 
inspection requirements of AD 2021-09-06. Those requirements are 
referenced in the service information identified previously, which, in 
turn, is referenced in paragraph (g) of this proposed AD.
    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 this 
service information at regulations.gov under Docket No. FAA-2024-0028.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 1,911 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
----------------------------------------------------------------------------------------------------------------
Inspection......................  4 work-hours x $85               $0   $340 per inspection  $649,740 per
                                   per hour = $340                       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 proposed AD.
    The FAA has included all known costs in its cost estimate. 
According to the manufacturer, however, some or all of the costs of 
this proposed AD may be covered under warranty, thereby reducing the 
cost impact on affected operators.

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:

[[Page 2517]]

0
a. Removing Airworthiness Directive (AD) 2021-09-06, Amendment 39-21519 
(86 FR 23595, May 4, 2021), and
0
b. Adding the following new AD:

The Boeing Company: Docket No. FAA-2024-0028; Project Identifier AD-
2023-00919-T.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by March 1, 2024.

(b) Affected ADs

    This AD replaces AD 2021-09-06, Amendment 39-21519 (86 FR 23595, 
May 4, 2021) (AD 2021-09-06).

(c) Applicability

    This AD applies to all The Boeing Company Model 737-600, -700, -
700C, -800, -900, and -900ER series airplanes, certificated in any 
category.

(d) Subject

    Air Transport Association (ATA) of America Code 53, Fuselage.

(e) Unsafe Condition

    This AD was prompted by reports of cracking in the station (STA) 
663.75 frame fitting outboard chords and failsafe straps adjacent to 
the stringer S-18A area and a determination that additional 
inspections are needed to address the unsafe condition. The FAA is 
issuing this AD to address cracking in the STA 663.75 frame fitting 
outboard chords and failsafe straps adjacent to the stringer S-18A 
straps, which could result in failure of a Principal Structural 
Element (PSE) to sustain limit load. The unsafe condition, if not 
addressed, could adversely affect the structural integrity of the 
airplane and result in loss of control of the airplane.

(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 737-53A1414 RB, Revision 1, dated 
November 20, 2023, do all applicable actions identified in, and in 
accordance with, the Accomplishment Instructions of Boeing Alert 
Requirements Bulletin 737-53A1414 RB, Revision 1, dated November 20, 
2023.
    Note 1 to paragraph (g): Guidance for accomplishing the actions 
required by this AD can be found in Boeing Alert Service Bulletin 
737-53A1414, Revision 1, dated November 20, 2023, which is referred 
to in Boeing Alert Requirements Bulletin 737-53A1414 RB, Revision 1, 
dated November 20, 2023.

(h) Exceptions to Service Information Specifications

    (1) Where the Condition and Compliance Time columns of the 
tables in the ``Compliance'' paragraph of Boeing Alert Requirements 
Bulletin 737-53A1414 RB, Revision 1, dated November 20, 2023, use 
the phrase ``the original issue date of Requirements Bulletin 737-
53A1414 RB,'' or ``the Revision 1 date of Requirements Bulletin 737-
53A1414 RB,'' this AD requires using ``the effective date of this 
AD.''
    (2) Where Boeing Alert Requirements Bulletin 737-53A1414 RB, 
Revision 1, dated November 20, 2023, 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, AIR-520, Continued Operational Safety 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: [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, AIR-
520, Continued Operational Safety 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 Owen Bley-Male, 
Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 
98198; telephone 206-231-3992; 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 (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 this AD specifies otherwise.
    (i) Boeing Alert Requirements Bulletin 737-53A1414 RB, Revision 
1, dated November 20, 2023.
    (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; website 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 material at the National Archives and 
Records Administration (NARA). For information on the availability 
of this material at NARA, visit www.archives.gov/federal-register/cfr/ibr-locations or email [email protected].

    Issued on January 5, 2024.
Victor Wicklund,
Deputy Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2024-00345 Filed 1-12-24; 8:45 am]
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