[Federal Register Volume 89, Number 127 (Tuesday, July 2, 2024)]
[Proposed Rules]
[Pages 54737-54739]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-14521]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2024-1880; Project Identifier AD-2023-01149-T]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for all The Boeing Company Model 737-600, -700, -700C, -800, -900, and 
-900ER series airplanes. This proposed AD was prompted by a report of a 
frame web crack at fuselage station (STA) 328 between stringers S-20R 
and S-21R common to the frame web notch. This proposed AD would require 
repetitive detailed inspections of the forward and aft sides of the 
frames and high frequency eddy current (HFEC) inspections of the frames 
for cracks and repairing any crack 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 August 16, 
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-2024-1880; 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, 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 Street, 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 under Docket No. FAA-2024-1880.

FOR FURTHER INFORMATION CONTACT: Bill Ashforth, Aviation Safety 
Engineer, FAA, 2200 South 216th Street, Des Moines, WA 98198; phone: 
206-231-3520; email: [email protected].

SUPPLEMENTARY INFORMATION:

Comments Invited

    The FAA invites you to send any written relevant data, views, or

[[Page 54738]]

arguments about this proposal. Send your comments to an address listed 
under ADDRESSES. Include ``Docket No. FAA-2024-1880; Project Identifier 
AD-2023-01149-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 Bill 
Ashforth, Aviation Safety Engineer, FAA, 2200 South 216th Street, Des 
Moines, WA 98198; phone: 206-231-3520; 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 has received a report that an operator of a Model 737-700 
airplane found a frame web crack at fuselage STA 328 between stringers 
S-20R and S-21R while performing a visual inspection of the electrical 
and electronics compartment during scheduled maintenance. The crack was 
common to the frame web notch and was approximately 0.85 inch long. The 
crack originated at a notch radius of the lower frame web that is 
subject to a load transfer from the inner chord of the upper frame. 
Because the load transfer is similar in adjacent areas, the frames at 
STA 312, STA 328, and STA 344 from stringers S-20R to S-23R are also 
affected. Model 737-600, -700C, -800, -900, and -900ER series airplanes 
have similar structure in the affected area and are also subject to 
this unsafe condition. Undetected cracks in the frame could lead to the 
inability of the principal structural element to sustain limit loads, 
which could result in the subsequent loss of structural integrity of 
the airplane.

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 737-53A1410 RB, 
dated October 11, 2023. This service information specifies procedures 
for repetitive detailed inspections of the forward and aft sides of the 
frames, and surface and open hole HFEC inspections of the frames, at 
STA 312 from S-20R to S-23R, STA 328 from S-19R to S-22R, and STA 344 
from S-20R to S-23R for cracks. This service information also specifies 
repairing any crack 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

    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-
2024-1880.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 1,583 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
----------------------------------------------------------------------------------------------------------------
Inspections......................  9 work-hours x $85             $0  $765 per inspection   $1,210,995 per
                                    per hour = $765 per                cycle.                inspection cycle.
                                    inspection cycle.
----------------------------------------------------------------------------------------------------------------

Estimated Costs of On-Condition Actions

    The extent of damage/cracking found during the proposed inspections 
could vary significantly from airplane to airplane. The FAA has no way 
of determining the type of repair or cost to repair any cracks on each 
airplane or the number of airplanes that may require repair.

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.

[[Page 54739]]

    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 adding the following new airworthiness 
directive:

The Boeing Company: Docket No. FAA-2024-1880; Project Identifier AD-
2023-01149-T.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by August 16, 2024.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to all The Boeing Company (Boeing) 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 a report of a frame web crack at 
fuselage station 328 between stringers S-20R and S-21R common to the 
frame web notch. The FAA is issuing this AD to address undetected 
cracks in the frame. The unsafe condition, if not addressed, could 
lead to the inability of the principal structural element to sustain 
limit loads, which could result in the subsequent loss of structural 
integrity 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 737-53A1410 RB, dated October 11, 2023, 
do all applicable actions identified in, and in accordance with, the 
Accomplishment Instructions of Boeing Alert Requirements Bulletin 
737-53A1410 RB, dated October 11, 2023.
    Note 1 to paragraph (g): Guidance for accomplishing the actions 
required by this AD can be found in Boeing Alert Service Bulletin 
737-53A1410, dated October 11, 2023, which is referred to in Boeing 
Alert Requirements Bulletin 737-53A1410 RB, dated October 11, 2023.

(h) Exceptions to Service Information Specifications

    (1) Where the ``Boeing Recommended Compliance Time'' column in 
the table under the ``Compliance'' paragraph of Boeing Alert 
Requirements Bulletin 737-53A1410 RB, dated October 11, 2023, refers 
to ``the Original Issue date of Requirements Bulletin 737-53A1410 
RB,'' this AD requires using the effective date of this AD.
    (2) Where Boeing Alert Requirements Bulletin 737-53A1410 RB, 
dated October 11, 2023, specifies contacting Boeing for repair 
instructions, this AD requires doing the repair using a method 
approved in accordance with the procedures 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 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 Bill Ashforth, 
Aviation Safety Engineer, FAA, 2200 South 216th Street, Des Moines, 
WA 98198; phone: 206-231-3520; email: [email protected].
    (2) Service information identified in this AD that is not 
incorporated by reference is available at the address specified in 
paragraph (k)(3) this AD.

(k) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference 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 737-53A1410 RB, dated 
October 11, 2023.
    (ii) [Reserved]
    (3) For service information, 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 material at the FAA, Airworthiness 
Products Section, Operational Safety Branch, 2200 South 216th 
Street, 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/[email protected]">www.archives.gov/federal-register/cfr/[email protected].

    Issued on June 26, 2024.
Suzanne Masterson,
Deputy Director, Integrated Certificate Management Division, Aircraft 
Certification Service.
[FR Doc. 2024-14521 Filed 7-1-24; 8:45 am]
BILLING CODE 4910-13-P