[Federal Register Volume 90, Number 54 (Friday, March 21, 2025)]
[Rules and Regulations]
[Pages 13276-13278]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-04782]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket FAA-2023-2234; Project Identifier AD-2023-00963-T; Amendment
39-22960; AD 2025-04-02]
RIN 2120-AA64
Airworthiness Directives; The Boeing Company Airplanes
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule; correction.
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SUMMARY: The FAA is correcting an airworthiness directive (AD) that was
published in the Federal Register. That AD applies to all The Boeing
Company Model 737-600, -700, -700C, -800, -900, and -900ER series
airplanes. As published, the service information referenced in certain
paragraphs of the regulatory text is incorrect, and the dates specified
in the ``System Airworthiness Limitation No. 3--Fan Blade Out
Conditions'' text and ``System Airworthiness Limitation No. 4--Engine
Nacelle Maintenance Errors'' text of figure 1 to paragraph (j) of the
regulatory text are incorrect. This document corrects those errors. In
all other respects, the original document remains the same.
DATES: This correction is effective April 8, 2025. The effective date
of AD 2025-04-02 remains April 8, 2025.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of April 8,
2025 (90 FR 11109, March 4, 2025).
ADDRESSES:
AD Docket: You may examine the AD docket at regulations.gov by
searching for and locating Docket No. FAA-2023-2234; 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 street address for Docket
Operations is listed above.
Material Incorporated by Reference:
For Boeing material 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.
You may view this material 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 under
Docket No. FAA-2023-2234.
FOR FURTHER INFORMATION CONTACT: Luis Cortez-Muniz, Aviation Safety
Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; telephone:
206-231-3958; email: [email protected].
SUPPLEMENTARY INFORMATION: AD 2025-04-02, Amendment 39-22960 (90 FR
11109, March 4, 2025) (AD 2025-04-02), requires replacing the fasteners
on the fan cowl support beam hinge fittings for certain airplanes and,
for all airplanes, requires modifying the radial restraint assembly and
installing an external doubler at the starter vent, or as an option,
installing a serviceable fan cowl. AD 2025-04-02 also requires revising
the existing maintenance or inspection program, as applicable, to
incorporate new airworthiness limitations. AD 2025-04-02 applies to all
The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER
series airplanes.
Need for Correction
As published, the service information referenced in certain
paragraphs of the regulatory text is incorrect, and the dates specified
in the ``System Airworthiness Limitation No. 3--Fan Blade Out
Conditions'' text and ``System Airworthiness Limitation No. 4--Engine
Nacelle Maintenance Errors'' text of figure 1 to paragraph (j) of the
regulatory text are incorrect.
Paragraphs (h)(4), (h)(5), and (h)(7) of the regulatory text
inadvertently referred to ``Boeing Special Attention Requirements
Bulletin 737-71-1938 RB, Revision 1, dated June 27, 2024,'' instead of
``Boeing Special Attention Requirements Bulletin 737-71-1937 RB,
Revision 1, dated June 27, 2024.''
Paragraph (h)(4) of the regulatory text also inadvertently referred
to ``Collins Aerospace Service Bulletin 737NG-71-007,'' instead of
``Collins Aerospace Service Bulletin 737NG-71-008,'' and inadvertently
referred to ``Material Necessary for Each Inlet Assembly'' instead of
``Material Necessary for Each Component.''
Paragraph (h)(7) of the regulatory text also included a reference
to Collins Service Bulletin 737NG-71-008 but inadvertently included a
date of ``July 28, 2023'' that is not necessary since the paragraph is
referring to the Collins Service Bulletin 737NG-71-008 identified in
Boeing Special Attention Requirements Bulletin 737-71-1937 RB, Revision
1, dated June 27, 2024, and should match how paragraphs (h)(4) and (5)
of the regulatory text refer to Collins Service Bulletin 737NG-71-008
without a date.
Paragraph (j) of the regulatory text inadvertently included a
reference to Boeing Special Attention Requirements Bulletin 737-71-1937
RB with the date of ``June 27, 2024'' instead of ``July 27, 2023.''
In addition, the date specified in the ``System Airworthiness
Limitation No. 3--Fan Blade Out Conditions'' text of figure 1 to
paragraph (j) of the regulatory text inadvertently referred to ``July
31, 2018'' instead of ``July 31, 2028,'' and the date specified in the
``System Airworthiness Limitation No. 4--Engine Nacelle Maintenance
Errors'' text of figure 1 to paragraph (j) of the regulatory text
inadvertently referred to ``December 31, 2019'' instead of ``December
31, 2029.''
Material Incorporated by Reference Under 1 CFR Part 51
The FAA reviewed Boeing Special Attention Requirements Bulletin
737-71-1937 RB, Revision 1, dated June 27, 2024. This material
specifies procedures for replacing, for certain airplanes, the
fasteners on the fan cowl support beam hinge fittings on the left and
right engine strut, and, for engine 1 and engine 2 for all airplanes,
modifying the radial restraint assembly and installing an external
doubler at the starter vent, or as an option, installing a serviceable
fan cowl. This material also specifies procedures to incorporate Boeing
737-600/700/700C/800/900/900ER Airworthiness Limitations (AWLs)
Document D626A001-9-01 ``System Airworthiness Limitation No. 2--Fan
Blade Out Conditions,'' ``System Airworthiness Limitation No. 3--Fan
Blade Out Conditions,'' and ``System Airworthiness Limitation No. 4--
Engine Nacelle Maintenance Errors'' into the operator's maintenance or
inspection program.
This material is reasonably available because the interested
parties have access to it through their normal course of business or by
the means identified in ADDRESSES.
[[Page 13277]]
Correction of Publication
This document corrects several errors and correctly adds the AD as
an amendment to 14 CFR 39.13. Although no part of the preamble and no
other part of the regulatory information has been corrected, the FAA is
publishing the entire rule in the Federal Register.
The effective date of this AD remains April 8, 2025.
Since this action only corrects service information referenced in
paragraphs that provide relief to the required actions and corrects a
date for an airworthiness limitation by specifying a later date, it has
no adverse economic impact and imposes no additional burden on any
person. Therefore, the FAA has determined that notice and public
comment procedures are unnecessary.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
Adoption of the Amendment
Accordingly, pursuant to the authority delegated to me by the
Administrator, the Federal Aviation Administration amends part 39 of
the Federal Aviation Regulations (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(f), 40113, 44701.
Sec. 39.13 [Corrected]
0
2. The FAA amends Sec. 39.13 by adding the following new airworthiness
directive:
2025-04-02 The Boeing Company: Amendment 39-22960; Docket No. FAA-
2023-2234; Project Identifier AD-2023-00963-T.
(a) Effective Date
This airworthiness directive (AD) is effective April 8, 2025.
(b) Affected ADs
None.
(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 71, Powerplant.
(e) Unsafe Condition
This AD was prompted by two engine fan blade-out (FBO) events
that resulted in the separation of engine inlet cowl and fan cowl
parts from the airplane. In one event, fan cowl parts damaged the
fuselage, which caused loss of pressurization and subsequent
emergency descent. The FAA is issuing this AD to address fan cowls
that are not strengthened, which, in the event of an FBO occurrence,
could depart the nacelle potentially damaging a stabilizer, or the
fan cowl striking the fuselage and window. The unsafe condition, if
not addressed, could result in loss of control of the airplane, or
in a rapid decompression and hazard to window-seated passengers aft
of the wing.
(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
Special Attention Requirements Bulletin 737-71-1937 RB, Revision 1,
dated June 27, 2024, do all applicable actions identified in, and in
accordance with, the Accomplishment Instructions of Boeing Special
Attention Requirements Bulletin 737-71-1937 RB, Revision 1, dated
June 27, 2024.
Note 1 to paragraph (g): Guidance for accomplishing the actions
required by this AD can be found in Boeing Special Attention Service
Bulletin 737-71-1937, Revision 1, dated June 27, 2024, which is
referred to in Boeing Special Attention Requirements Bulletin 737-
71-1937 RB, Revision 1, dated June 27, 2024.
(h) Exceptions to Service Information Specifications
(1) Where the service information referenced in paragraph (g) of
this AD specifies contacting Boeing or Collins Aerospace for repair
instructions: This AD requires doing the repair before further
flight using a method approved in accordance with the procedures
specified in paragraph (k) of this AD.
(2) Where the Compliance Time columns of the tables in the
``Compliance'' paragraph of Boeing Special Attention Requirements
Bulletin 737-71-1937 RB, Revision 1, dated June 27, 2024, refer to
the original issue date of Requirements Bulletin 737-71-1937 RB,
this AD requires using the effective date of this AD.
(3) Where System Airworthiness Limitation No. 4, as identified
in Boeing Special Attention Requirements Bulletin 737-71-1937 RB,
Revision 1, dated June 27, 2024, requires incorporation of solutions
to address potential engine nacelle maintenance errors, solutions
consist of a re-designed fan cowl latch and keeper and application
of high visibility paint on the interior of the integrated drive
generator (IDG) door.
(4) Where Collins Aerospace Service Bulletin 737NG-71-008
referenced in Boeing Special Attention Requirements Bulletin 737-71-
1937 RB, Revision 1, dated June 27, 2024, specifies use of Bonderite
M-CR 1200S Aero, 10P4-2NF primer, EC-117S converter, TR19 thinner,
or T20 thinner, this AD also allows for equivalent material
substitutes as specified in paragraph 2.C., ``Material Necessary for
Each Component,'' of Collins Aerospace Service Bulletin 737NG-71-008
referenced in Boeing Special Attention Requirements Bulletin 737-71-
1937 RB, Revision 1, dated June 27, 2024.
(5) Where Collins Service Bulletin 737NG-71-008 referenced in
Boeing Special Attention Requirements Bulletin 737-71-1937 RB,
Revision 1, dated June 27, 2024, states to apply primer ``per Boeing
document D6-1816,'' this AD requires replacing that text with ``per
Boeing document D6-1816 or Boeing SOPM 20-41-02.''
(6) Where Boeing Special Attention Requirements Bulletin 737-71-
1937 RB, Revision 1, dated June 27, 2024, requires (Option 1)
(Action 3) to be accomplished after (Option 1) (Action 2), this AD
allows these two actions to be accomplished concurrently.
(7) Where Collins Service Bulletin 737NG-71-008 referenced in
Boeing Special Attention Requirements Bulletin 737-71-1937 RB,
Revision 1, dated June 27, 2024, specifies to topcoat over the
repair area to agree with the initial production topcoat, this AD
also allows topcoat to match the surrounding topcoat.
(i) No Alternative Actions
After the existing maintenance or inspection program has been
revised as required by paragraph (g) of this AD, no alternative
actions may be used unless the actions are approved as an
alternative method of compliance (AMOC) in accordance with the
procedures specified in paragraph (k) of this AD.
(j) Credit for Previous Actions
This paragraph provides credit for the actions specified in
paragraph (g) of this AD, if those actions were performed before the
effective date of this AD using Boeing Special Attention
Requirements Bulletin 737-71-1937 RB, dated July 27, 2023, provided
where Tables 1 through 4 of Boeing Special Attention Requirements
Bulletin 737-71-1937 RB, dated July 27, 2023, specify incorporating
737-600/700/700C/800/900/900ER Airworthiness Limitations (AWLs)
Document D626A001-9-01 ``System Airworthiness Limitation No. 2--Fan
Blade Out Conditions'' and ``System Airworthiness Limitation No. 3--
Fan Blade Out Conditions'' into the operators' maintenance program,
the information specified in figure 1 to paragraph (j) of this AD
has been incorporated into the airworthiness limitations.
[[Page 13278]]
Figure 1 to Paragraph (j)--System Airworthiness Limitations
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SYSTEM AIRWORTHINESS LIMITATION No. 2
FAN BLADE OUT CONDITIONS
All aircraft must install the following modifications: (1) engines
inlets with new spacer design and increased fastener capability (2) fan
cowls with new radial restraint fitting hooks, new radial restraint
clips, and an external doubler at the starter vent (3) fan cowl support
beam fastener changes (except for 737-900ER aircraft, because the fan
cowl support beam fastener changes are already incorporated). All
aircraft that have not incorporated these modifications cannot operate
past July 31, 2028 unless upgraded to new hardware that is fully
compliant to Sec. Sec. 25.901(c) and Appendix K25.1.1 to Part 25.
Boeing will release all service data to allow retrofit of hardware
updates to the CFM56-7B nacelle prior to that date.
SYSTEM AIRWORTHINESS LIMITATION No. 3
FAN BLADE OUT CONDITIONS
All aircraft delivered without the Performance Improvement Package (PIP)
must install engine exhaust nozzle structural stiffening elements. All
aircraft that have not incorporated these modifications cannot operate
past July 31, 2028 unless upgraded to new hardware that is fully
compliant to Sec. Sec. 25.901(c) and Appendix K25.1.1 to Part 25.
Boeing will release all service data to allow retrofit of hardware
updates to the CFM56-7B nacelle prior to that date.
SYSTEM AIRWORTHINESS LIMITATION No. 4
ENGINE NACELLE MAINTENANCE ERRORS
All aircraft must incorporate solutions to address potential maintenance
errors, e.g., the failure to completely latch the fan cowl or the can
cowl integrated drive generator (IDG) door. All aircraft that have not
incorporated changes to become fully compliance with Sec. Sec.
25.901(c) and Appendix K25.1.1 to Part 25 cannot be operated past
December 31, 2029.
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(k) 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
(l)(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.
(l) Related Information
(1) For more information about this AD, contact Luis Cortez-
Muniz, Aviation Safety Engineer, FAA, 2200 South 216th St., Des
Moines, WA 98198; telephone: 206-231-3958; email: [email protected].
(2) For Collins material identified in this AD that is not
incorporated by reference, contact Collins Aerospace, 15701 West
95th Street, Lenexa, KS 66219; email [email protected];
website tpi.beaerospace.com/Authentication.
(3) Boeing material identified in this AD that is not
incorporated by reference is available at the address specified in
paragraph (m)(3) this AD.
(m) Material Incorporated by Reference
(1) The Director of the Federal Register approved the
incorporation by reference (IBR) of the material listed in this
paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
(2) You must use this material as applicable to do the actions
required by this AD, unless this AD specifies otherwise.
(3) The following material was approved for IBR on April 8, 2025
(90 FR 11109, March 4, 2025).
(i) Boeing Special Attention Requirements Bulletin 737-71-1937
RB, Revision 1, dated June 27, 2024.
(ii) [Reserved]
(4) For Boeing material 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.
(5) You may view this material 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 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 March 17, 2025.
Victor Wicklund,
Deputy Director, Integrated Certificate Management Division, Aircraft
Certification Service.
[FR Doc. 2025-04782 Filed 3-20-25; 8:45 am]
BILLING CODE 4910-13-P