Published 2025-11-28 · Federal Register document 2025-21477
Airworthiness Directives; The Boeing Company Airplanes
Publication summary
The FAA is superseding Airworthiness Directive (AD) 2022-15- 06, which applied to all The Boeing Company Model 777-200, -200LR, - 300, -300ER, and 777F series airplanes. AD 2022-15-06 required disconnecting certain connectors and capping and stowing the wires that had been attached to the affected transorb modules. Since the FAA issued AD 2022-15-06, the agency has determined additional connectors are affected. Also, a replacement has been developed to address the unsafe condition, which would terminate the existing actions. This AD continues to require the actions specified in AD 2022-15-06 and requires those actions for additional connectors. This AD also requires determining if affected transorb modules are installed, replacing or testing affected transorb modules, and applicable on-condition actions. This AD also prohibits the installation of affected parts. The FAA is issuing this AD to address the unsafe condition on these products.
Why this record is shown
Source: Federal Register annual FAA metadata. Acquired 2026-09-03T22:24:20.413248+00:00. The title, summary and date are source facts.
- Source revision
- federal_register_ad_metadata_2025-67d39c2af9a91434
- Source row
- results[288]
- Raw source SHA-256
- 67d39c2af9a914349adee3ee1cee836da6415ed54d2b01123da75b563b687ab0
Final-rule publication
Recorded publication clauses
- AD identifier printed in this edition
- 2025-21-02
- Effective date printed in this edition
- 2026-01-02
Read 14 complete recorded clauses
Effective Date
(a) Effective Date
This airworthiness directive (AD) is effective January 2, 2026.
Exact source excerpt. Text positions 18351–18440, end exclusive, in the original decoded publication. SHA-256: 4556fdb31f0e36da6392f60dd6f701e3f30903a6da35f4f85434efde1b3414a4
Affected ADs
(b) Affected ADs
This AD replaces AD 2022-15-06, Amendment 39-22126 (87 FR 47334,
August 3, 2022) (AD 2022-15-06).
Exact source excerpt. Text positions 18440–18562, end exclusive, in the original decoded publication. SHA-256: c5abe88a3758da1eb114c432b34d9592c5c7f1dc2d261b4c6e480a6b3eab46ac
Applicability wording · Applicability
(c) Applicability
This AD applies to all The Boeing Company Model 777-200, -200LR,
-300, -300ER, and 777F series airplanes, certificated in any
category.
Exact source excerpt. Text positions 18562–18724, end exclusive, in the original decoded publication. SHA-256: b674a34c84fdfddce70ab734ab1f39e41fcee3f5a6af63aac598dbc5d608819d
Subject
(d) Subject
Air Transport Association (ATA) of America Code 27, Flight
controls.
Exact source excerpt. Text positions 18724–18812, end exclusive, in the original decoded publication. SHA-256: 5df668a44f125df3e991e4d0d4055a7abf4e497975e862633d97c2c7cacf4016
Unsafe Condition
(e) Unsafe Condition
This AD was prompted by high electrical resistance within the
gust suppression sensor (GSS) transorb modules due to corrosion on
the transorb threads and insufficient engagement of the anti-
rotation teeth. The FAA is issuing this AD to address high
electrical resistance in both transorb modules, which can result in
two actuator control electronics (ACEs) being exposed to damaging
lightning transient voltages in excess of the qualification levels,
potentially inducing erroneous or oscillatory outputs to flight
control surfaces. The unsafe condition, if not addressed, could
result in loss of control of the airplane.
Exact source excerpt. Text positions 18812–19470, end exclusive, in the original decoded publication. SHA-256: b78c36991eeadef863fc8b1f8625526ba829a51426841a47f9a8926bf73f1480
Compliance
(f) Compliance
Comply with this AD within the compliance times specified,
unless already done.
Exact source excerpt. Text positions 19470–19572, end exclusive, in the original decoded publication. SHA-256: 00fbfa31932483f627d0ce0a11cbd2e35e15d9231842b91ac85623ce533912d3
Retained Requirement To Disconnect, Cap, and Stow Transorb Module Connectors, With Revised Affected Airplanes
(g) Retained Requirement To Disconnect, Cap, and Stow Transorb Module
Connectors, With Revised Affected Airplanes
For airplanes with an original airworthiness certificate or
original export certificate of airworthiness issued on or before the
effective date of this AD: This paragraph restates the requirements
of paragraph (g) of AD 2022-15-06, with revised affected airplanes.
At the later of the times specified in paragraphs (g)(1) and (2) of
this AD: Disconnect the connectors and cap and stow the wires to
bundles/connectors W7314/D02006P and W7579/D02005P from the transorb
module part numbers CLPT-12SP-06, CLPT-12SP-07, and CLPT-12SP-67.
Note 1 to the introductory text of paragraph (g): Guidance on
locating wire bundles/connectors W7314/D02006P and W7579/D02005P can
be found in Section 05-55-43 of the Boeing 777 aircraft maintenance
manual.
Note 2 to the introductory text of paragraph (g): Guidance on
capping and stowing the wires once they are disconnected can be
found in Section 20-10-11 of the Boeing Standard Wiring Practices
Manual.
(1) Before the accumulation of 75,000 total flight hours or
23,000 total flight cycles, whichever occurs first.
(2) Within 3 months after August 18, 2022 (the effective date of
AD 2022-15-06).
Exact source excerpt. Text positions 19572–20857, end exclusive, in the original decoded publication. SHA-256: c90dfd3c0c79154e8a73cdf80ce2881b6e81384a7b08a2f105bf4e9388a10b43
New Requirement To Disconnect, Cap, and Stow Certain Other Transorb Module Connectors
(h) New Requirement To Disconnect, Cap, and Stow Certain Other Transorb
Module Connectors
For airplanes with an original airworthiness certificate or
original export certificate of airworthiness issued on or before the
effective date of this AD: At the later of the times specified in
paragraphs (h)(1) and (2) of this AD: Disconnect the connectors and
cap and stow the wires to bundles/connectors W6313/D02098P or W7314/
D02099P from the transorb module part numbers CLPT-12SP-06, CLPT-
12SP-07, and CLPT-12SP-67.
Note 3 to the introductory text of paragraph (h): Guidance on
locating wire bundles/connectors W6313/D02098P and W7314/D02099P can
be found in Section 05-55-43 of the Boeing 777 aircraft maintenance
manual.
Note 4 to the introductory text of paragraph (h): Guidance on
capping and stowing the wires once they are disconnected can be
found in Section 20-10-11 of the Boeing Standard Wiring Practices
Manual.
(1) Before the accumulation of 75,000 total flight hours or
23,000 total flight cycles, whichever occurs first.
(2) Within 3 months after the effective date of this AD.
Exact source excerpt. Text positions 20857–21982, end exclusive, in the original decoded publication. SHA-256: 03aa9904e473727b9febba264221a1fb5602c055895d701c19dffd93c53392f5
New Required Actions
(i) New Required Actions
(1) For airplanes with an original airworthiness certificate or
original export certificate of airworthiness issued on or before the
effective date of this AD: At the later of the times specified in
paragraph (i)(1)(i) or (ii) of this AD, do an inspection to
determine if any airplane has a transorb module with part number
CLPT-12SP-06, CLPT-12SP-07, or CLPT-12SP-67 installed. A review of
airplane maintenance records is acceptable in lieu of the inspection
if the part numbers can be conclusively determined from that review.
(i) Within 24 months after the effective date of this AD.
(ii) Within 24 months after the date of issuance of the original
standard airworthiness certificate or the original export
certificate of airworthiness.
(2) If, during any inspection or records review required by
paragraph (i)(1) of this AD, any transorb module with part number
CLPT-12SP-06, CLPT-12SP-07, or CLPT-12SP-67 is found: Except as
specified by paragraph (j) of this AD, at the applicable times
specified in the ``Compliance'' paragraph of Boeing Alert
Requirements Bulletin 777-27A0125 RB, dated February 3, 2023, do all
applicable actions identified in, and in accordance with, the
Accomplishment Instructions of Boeing Alert Requirements
[[Page 54559]]
Bulletin 777-27A0125 RB, dated February 3, 2023. Doing the
replacement required by this paragraph terminates the requirements
of paragraphs (g) and (h) of this AD.
Note 5 to paragraph (i)(2): Guidance for accomplishing the
actions required by paragraph (i)(2) of this AD can be found in
Boeing Alert Service Bulletin 777-27A0125, dated February 3, 2023,
which is referred to in Boeing Alert Requirements Bulletin 777-
27A0125 RB, dated February 3, 2023.
Exact source excerpt. Text positions 21982–23760, end exclusive, in the original decoded publication. SHA-256: b6bb3e0d71abb436c17182f61695f3eb81d706e93908e0a58ea14abc65217263
Exception to Requirements Bulletin Specifications
(j) Exception to Requirements Bulletin Specifications
Where the Compliance Time column of the table in the
``Compliance'' paragraph of Boeing Alert Requirements Bulletin 777-
27A0125 RB, dated February 3, 2023, refers to the original issue
date of Requirements Bulletin 777-27A0125 RB, this AD requires using
the effective date of this AD.
Exact source excerpt. Text positions 23760–24109, end exclusive, in the original decoded publication. SHA-256: 4073cad6f29535bc7ca8c7ebaa5ede44e84f8e650d16e1d31155792ed8c88688
Parts Installation Prohibition
(k) Parts Installation Prohibition
As of the effective date of this AD, no person may install a
transorb module, part numbers CLPT-12SP-06, CLPT-12SP-07, and CLPT-
12SP-67, on any airplane.
Exact source excerpt. Text positions 24109–24306, end exclusive, in the original decoded publication. SHA-256: 9a5b0c669ff4c61df89f5f0e51e5ee5c68d445135b7ed383050638f3324feec2
Alternative Methods of Compliance (AMOCs)
(l) 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
(m)(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.
(4) AMOCs approved for AD 2022-15-06 are approved as AMOCs for
the corresponding provisions of paragraph (g) of this AD.
Exact source excerpt. Text positions 24306–25715, end exclusive, in the original decoded publication. SHA-256: 8515d322a188c7bf2005d6374d8afb29f37ab82dfaabaa897002ea4f1f774636
Related Information
(m) Related Information
(1) For more information about this AD, contact Raja
Vengadasalam, Aviation Safety Engineer, FAA, 2200 South 216th St.,
Des Moines, WA 98198; phone: 206-231-3859; email:
[email protected].
(2) Material identified in this AD that is not incorporated by
reference is available at the address specified in paragraph (n)(3)
of this AD.
Exact source excerpt. Text positions 25715–26086, end exclusive, in the original decoded publication. SHA-256: 73023de3c937a1858433b0d078328bce7c3a9f9b7e1d0df5f135c933d3cfa1c6
Material Incorporated by Reference
(n) Material Incorporated by Reference
(1) The Director of the Federal Register approved the
incorporation by reference 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 the AD specifies otherwise.
(i) Boeing Alert Requirements Bulletin 777-27A0125 RB, dated
February 3, 2023.
(ii) [Reserved]
(3) For the 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.
(4) 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.
(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].
Exact source excerpt. Text positions 26086–27250, end exclusive, in the original decoded publication. SHA-256: e9eb43d7e413c6456cac55d1a260bd31d7c6805a8af2b2f83af9c265270d4d34
Explicit historical replacement wording
Find all recorded historical references to AD 2025-21-02 · 0 printed reference observations in this pinned collection.
These are observations from one dated publication. Current legal status is unknown; aircraft applicability, installed configuration, compliance and burden require separate evidence. Missing or unparsed conditions remain unknown.
Why these observations are shown
They were extracted offline from the same immutable official HTML source as the complete recorded text. The dated source wording, original text coordinates and exact quote digests are retained. PDF/text agreement and current regulatory effect have not been qualified.
Observation revision: whole-ad-publication-clause-observations-1.0.1. Text SHA-256: 06a35d341189a0d0a1da1cd6cd7f2c24629679d29bb010c84838007a71357710. Source manifest: 0f2ef8ef5330500b73e63f35b05c5af24b33de4cb0eb72ca7398b47441c2aec9.
Official source · 2025-11-28
Publication text
This is the complete recorded text of this dated publication.
Current legal effect is unknown. Aircraft applicability, installed configuration and compliance require separate evidence. PDF/text agreement has not been evaluated.
Read the complete official publication text
[Federal Register Volume 90, Number 227 (Friday, November 28, 2025)]
[Rules and Regulations]
[Pages 54555-54559]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-21477]
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2024-2144; Project Identifier AD-2024-00424-T;
Amendment 39-23174; AD 2025-21-02]
RIN 2120-AA64
Airworthiness Directives; The Boeing Company Airplanes
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule.
-----------------------------------------------------------------------
SUMMARY: The FAA is superseding Airworthiness Directive (AD) 2022-15-
06, which applied to all The Boeing Company Model 777-200, -200LR, -
300, -300ER, and 777F series airplanes. AD 2022-15-06 required
disconnecting certain connectors and capping and stowing the wires that
had been attached to the affected transorb modules. Since the FAA
issued AD 2022-15-06, the agency has determined additional connectors
are affected. Also, a replacement has been developed to address the
unsafe condition, which would terminate the existing actions. This AD
continues to require the actions specified in AD 2022-15-06 and
requires those actions for additional connectors. This AD also requires
determining if affected transorb modules are installed, replacing or
testing affected transorb modules, and applicable on-condition actions.
This AD also prohibits the installation of affected parts. The FAA is
issuing this AD to address the unsafe condition on these products.
DATES: This AD is effective January 2, 2026.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of January 2,
2026.
ADDRESSES:
AD Docket: You may examine the AD docket at regulations.gov under
Docket No. FAA-2024-2144; 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
[[Page 54556]]
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.
Material Incorporated by Reference:
<bullet> 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.
<bullet> 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-2024-2144.
FOR FURTHER INFORMATION CONTACT: Raja Vengadasalam, Aviation Safety
Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 206-
231-3859; email: [email protected].
SUPPLEMENTARY INFORMATION:
Background
The FAA issued a notice of proposed rulemaking (NPRM) to amend 14
CFR part 39 to supersede AD 2022-15-06, Amendment 39-22126 (87 FR
47334, August 3, 2022) (AD 2022-15-06). AD 2022-15-06 applied to all
The Boeing Company Model 777-200, -200LR, -300, -300ER, and 777F series
airplanes. The NPRM was published in the Federal Register on September
26, 2024 (89 FR 78827). The NPRM was prompted by the determination that
connectors that were not identified in AD 2022-15-06 are affected and
by the development of a replacement action to address the unsafe
condition, which would terminate the existing actions. In the NPRM, the
FAA proposed to continue to require the actions specified in AD 2022-
15-06 and require those actions for additional connectors. The NPRM
also proposed to require determining if affected transorb modules are
installed, replacing or testing affected transorb modules, and
applicable on-condition actions. The NPRM also proposed to prohibit the
installation of affected parts. The NPRM was prompted by high
electrical resistance within the gust suppression sensor (GSS) transorb
modules due to corrosion on the transorb threads and insufficient
engagement of the anti-rotation teeth. The FAA is issuing this AD to
address high electrical resistance in both transorb modules, which can
result in two actuator control electronics (ACEs) being exposed to
damaging lightning transient voltages in excess of the qualification
levels, potentially inducing erroneous or oscillatory outputs to flight
control surfaces. The unsafe condition, if not addressed, could result
in loss of control of the airplane.
Discussion of Final Airworthiness Directive
Comments
The FAA received comments from Air Line Pilots Association,
International (ALPA), and Cathay Pacific, who supported the NPRM
without change.
The FAA received additional comments from five commenters,
including American Airlines, Boeing, FedEx Express, and United Airlines
(United). The following presents the comments received on the NPRM and
the FAA's response to each comment.
Request To Revise the Applicability
Boeing requested that paragraph (c) of the proposed AD be revised
to limit the applicability to the airplanes affected by Boeing Alert
Requirements Bulletin 777-27A0125 RB, dated February 3, 2023. Boeing
stated that if the AD applies to all The Boeing Company Model 777-200,
-200LR, -300, -300ER, and 777F series airplanes (including the
airplanes after line number 1726-the airplanes that will have this
change already incorporated in production), then the airplanes
delivered after the effective date of this AD would need to document
that these AD actions were incorporated in production in an AD Letter
(ADL), stating that the airplane is not affected by the AD.
The FAA disagrees with Boeing's request that paragraph (c) of this
AD be revised because the transorbs are rotable and these parts could
later be installed on airplanes that were initially delivered with
acceptable parts, thereby subjecting those airplanes to the unsafe
condition. All airplanes are subject to the parts installation
prohibition specified in paragraph (k) of this AD, which does not allow
affected parts to be installed as of the effective date of the AD.
The FAA notes that airplanes produced after the effective date of
this AD do not need to document that the actions in Boeing Alert
Requirements Bulletin 777-27A0125 RB, dated February 3, 2023, were done
because paragraphs (i)(1) and (2) of this AD only apply to airplanes
produced on or before the effective date of this AD. Additionally, the
FAA has revised paragraphs (g) and (h) of this AD to limit those
requirements to airplanes produced on or before the effective date of
this AD since airplanes produced after the effective date of this AD
will not be delivered with the affected transorb modules or connectors.
Request To Allow Optional Action to the Replacement of Required Actions
FedEx Express requested that the FAA revise paragraph (i)(2) of the
proposed AD to allow continued flight with the GSS connectors stowed
per paragraphs (g) and (h) of the proposed AD, as an optional action.
The commenter stated that the reactivation in paragraph (i)(2) of the
proposed AD does not appear to lend any effort towards airworthiness of
the aircraft outside of passenger comfort. Additionally, the commenter
noted that such a system is not a requirement of 14 CFR part 25 and
therefore expenditure of valuable time and resources on a system not
appreciably utilized by a cargo carrier would seem pointless.
The FAA acknowledges the commenter's request. The purpose of this
AD is to restore the affected fleet to an acceptable level of safety.
The FAA is issuing this AD to address high electrical resistance in
both transorb modules, which can result in two actuator control
electronics (ACEs) being exposed to damaging lightning transient
voltages in excess of the qualification levels, potentially inducing
erroneous or oscillatory outputs to flight control surfaces and could
result in loss of control of the airplane. Allowing the connectors to
be disconnected long-term may not address the unsafe condition in the
affected fleet, as an operator may inadvertently reconnect the affected
connectors in the future. Therefore, the replacement of affected
connectors must be done to address the unsafe condition. However, any
person may request approval of an alternative method of compliance
(AMOC) under the provisions of paragraph (l)(2) of this AD. This AD has
not been changed regarding this request.
Request for Removing/Revising Paragraphs (g) and (h) of the Proposed AD
and References to Connector D02099P
Boeing requested that the FAA remove paragraph (h) of the proposed
AD, update paragraph (g) of the proposed AD by referring to bundle/
connector W6313/D02098P, and remove references to connector D02099P
from ``Actions Since AD-2022-15-06 Was Issued'' in the NPRM. Boeing
suggested some revised wording for paragraph (g) of the proposed AD to
account for additional wire to bundles/connector part numbers that are
present on some
[[Page 54557]]
airplanes. Boeing stated paragraph (h) of the proposed AD could be
misleading to operators as it does not highlight that the difference in
the bundle and connector callouts are line number dependent. In
addition, Boeing stated the connectors called out in paragraph (h) of
the proposed AD are incorrect and reference two disconnect points on
the same wire bundle. Boeing recommended that connector D02099P not be
referenced as a disconnect point in the NPRM.
United requested that the FAA revise paragraph (h) of the proposed
AD to allow for disconnecting one of the connectors rather than the
referenced ``W6313/D02098P and W7314/D02099P,'' which would require
operators to unnecessarily disconnect both. United stated that the
connectors are in the same wiring circuit so disconnecting either
connector D02098P or D02099P would effectively deactivate the upper
gust suppression transducer circuit. United noted it has disconnected,
capped, and stowed connector D02099P and connector D02098P remains
connected for these aircraft as allowed in AMOC letter 783-22-11124,
dated January 17, 2023.
American Airlines requested that the FAA change references to wire
bundles/connectors from ``W6313/D02098P and W7314/D02099P'' to ``W6313/
D02098P or W7314/D02099P,'' as disconnecting either from the transorb
module sufficiently complies with the level of safety required by the
proposed AD.
The FAA agrees with rewording paragraph (h) of this AD to address
the two disconnect points of the wire bundles being referenced as
``W6313/D02098P and W7314/D02099P'' to ``W6313/D02098P or W7314/
D02099P'' to alleviate confusion of referencing disconnecting both from
the transorb module; the disconnection of either bundle/connector
provides an equivalent level of safety. Paragraph (h) of this AD has
been updated to the reference above.
The FAA disagrees with removing paragraph (h) of this AD and
updating paragraph (g) of this AD because either bundles/connectors
W6313/D02098P or W7314/D02099P can be disconnected to address the
unsafe condition. This AD has not been changed to remove the actions
required by paragraph (h) of this AD.
Regarding the request to revise the wording in paragraph (g) of
this AD, the FAA agrees to clarify. AMOC letter 783-22-11124, dated
January 17, 2023, allows operators to use the wording suggested by
Boeing. Paragraph (l)(4) of this AD allows operators to use AMOCs
previously approved for AD 2022-15-06 for the corresponding provisions
of paragraph (g) of this AD. Therefore, no change to this AD is
necessary.
Regarding the request to revise ``Actions Since AD-2022-15-06 Was
Issued'' in the NPRM, that language is not restated in this final rule;
however, the FAA acknowledges that the text should have stated
``disconnect the connectors and cap and stow the wires to bundles/
connectors W6313/D02098P or W7314/D02099P.''
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.
Material Incorporated by Reference Under 1 CFR Part 51
The FAA reviewed Boeing Alert Requirements Bulletin 777-27A0125 RB,
dated February 3, 2023. This material specifies procedures for
replacing affected transorb modules with new or serviceable transorb
modules or testing affected transorb modules and accomplishing
applicable on-condition actions. The on-condition actions include part
marking any module that meets certain specifications or replacing any
modules that do not meet the specifications.
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 the ADDRESSES section.
Costs of Compliance
The FAA estimates that this AD affects 312 airplanes of U.S.
registry. The FAA estimates the following costs to comply with this AD:
Estimated Costs
----------------------------------------------------------------------------------------------------------------
Cost on U.S.
Action Labor cost Parts cost Cost per product operators
----------------------------------------------------------------------------------------------------------------
Disconnecting connectors, 3 work-hours x $85 per $0............... $255............. $79,560.
capping and stowing wires hour = $255.
(retained actions from AD 2022-
15-06).
Disconnecting additional 3 work-hours x $85 per $0............... $255............. $79,560.
connectors, capping and hour = $255.
stowing wires (new action).
Determining if affected Up to 3 work-hours x Up to $3,668..... Up to $3,923..... Up to $1,223,976.
transorb modules are $85 per hour = $255.
installed, and replacing or
testing affected modules (new
action).
----------------------------------------------------------------------------------------------------------------
The FAA estimates the following costs to do any necessary on-
condition actions that would be required based on the results of the
testing. The agency has no way of determining the number of aircraft
that might need these actions:
On-Condition Costs
----------------------------------------------------------------------------------------------------------------
Action Labor cost Parts cost Cost per product
----------------------------------------------------------------------------------------------------------------
Part marking or replacing affected Up to 3 work-hours x $85 Up to $3,668.......... Up to $3,923.
modules. per hour = $255.
----------------------------------------------------------------------------------------------------------------
[[Page 54558]]
The FAA has included all known costs in its cost estimate.
According to the manufacturer, however, some or all of the costs of
this 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
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:
0
a. Removing Airworthiness Directive (AD) 2022-15-06, Amendment 39-22126
(87 FR 47334, August 3, 2022); and
0
b. Adding the following new AD:
2025-21-02 The Boeing Company: Amendment 39-23174; Docket No. FAA-
2024-2144; Project Identifier AD-2024-00424-T.
(a) Effective Date
This airworthiness directive (AD) is effective January 2, 2026.
(b) Affected ADs
This AD replaces AD 2022-15-06, Amendment 39-22126 (87 FR 47334,
August 3, 2022) (AD 2022-15-06).
(c) Applicability
This AD applies to all The Boeing Company Model 777-200, -200LR,
-300, -300ER, and 777F series airplanes, certificated in any
category.
(d) Subject
Air Transport Association (ATA) of America Code 27, Flight
controls.
(e) Unsafe Condition
This AD was prompted by high electrical resistance within the
gust suppression sensor (GSS) transorb modules due to corrosion on
the transorb threads and insufficient engagement of the anti-
rotation teeth. The FAA is issuing this AD to address high
electrical resistance in both transorb modules, which can result in
two actuator control electronics (ACEs) being exposed to damaging
lightning transient voltages in excess of the qualification levels,
potentially inducing erroneous or oscillatory outputs to flight
control surfaces. The unsafe condition, if not addressed, could
result in loss of control of the airplane.
(f) Compliance
Comply with this AD within the compliance times specified,
unless already done.
(g) Retained Requirement To Disconnect, Cap, and Stow Transorb Module
Connectors, With Revised Affected Airplanes
For airplanes with an original airworthiness certificate or
original export certificate of airworthiness issued on or before the
effective date of this AD: This paragraph restates the requirements
of paragraph (g) of AD 2022-15-06, with revised affected airplanes.
At the later of the times specified in paragraphs (g)(1) and (2) of
this AD: Disconnect the connectors and cap and stow the wires to
bundles/connectors W7314/D02006P and W7579/D02005P from the transorb
module part numbers CLPT-12SP-06, CLPT-12SP-07, and CLPT-12SP-67.
Note 1 to the introductory text of paragraph (g): Guidance on
locating wire bundles/connectors W7314/D02006P and W7579/D02005P can
be found in Section 05-55-43 of the Boeing 777 aircraft maintenance
manual.
Note 2 to the introductory text of paragraph (g): Guidance on
capping and stowing the wires once they are disconnected can be
found in Section 20-10-11 of the Boeing Standard Wiring Practices
Manual.
(1) Before the accumulation of 75,000 total flight hours or
23,000 total flight cycles, whichever occurs first.
(2) Within 3 months after August 18, 2022 (the effective date of
AD 2022-15-06).
(h) New Requirement To Disconnect, Cap, and Stow Certain Other Transorb
Module Connectors
For airplanes with an original airworthiness certificate or
original export certificate of airworthiness issued on or before the
effective date of this AD: At the later of the times specified in
paragraphs (h)(1) and (2) of this AD: Disconnect the connectors and
cap and stow the wires to bundles/connectors W6313/D02098P or W7314/
D02099P from the transorb module part numbers CLPT-12SP-06, CLPT-
12SP-07, and CLPT-12SP-67.
Note 3 to the introductory text of paragraph (h): Guidance on
locating wire bundles/connectors W6313/D02098P and W7314/D02099P can
be found in Section 05-55-43 of the Boeing 777 aircraft maintenance
manual.
Note 4 to the introductory text of paragraph (h): Guidance on
capping and stowing the wires once they are disconnected can be
found in Section 20-10-11 of the Boeing Standard Wiring Practices
Manual.
(1) Before the accumulation of 75,000 total flight hours or
23,000 total flight cycles, whichever occurs first.
(2) Within 3 months after the effective date of this AD.
(i) New Required Actions
(1) For airplanes with an original airworthiness certificate or
original export certificate of airworthiness issued on or before the
effective date of this AD: At the later of the times specified in
paragraph (i)(1)(i) or (ii) of this AD, do an inspection to
determine if any airplane has a transorb module with part number
CLPT-12SP-06, CLPT-12SP-07, or CLPT-12SP-67 installed. A review of
airplane maintenance records is acceptable in lieu of the inspection
if the part numbers can be conclusively determined from that review.
(i) Within 24 months after the effective date of this AD.
(ii) Within 24 months after the date of issuance of the original
standard airworthiness certificate or the original export
certificate of airworthiness.
(2) If, during any inspection or records review required by
paragraph (i)(1) of this AD, any transorb module with part number
CLPT-12SP-06, CLPT-12SP-07, or CLPT-12SP-67 is found: Except as
specified by paragraph (j) of this AD, at the applicable times
specified in the ``Compliance'' paragraph of Boeing Alert
Requirements Bulletin 777-27A0125 RB, dated February 3, 2023, do all
applicable actions identified in, and in accordance with, the
Accomplishment Instructions of Boeing Alert Requirements
[[Page 54559]]
Bulletin 777-27A0125 RB, dated February 3, 2023. Doing the
replacement required by this paragraph terminates the requirements
of paragraphs (g) and (h) of this AD.
Note 5 to paragraph (i)(2): Guidance for accomplishing the
actions required by paragraph (i)(2) of this AD can be found in
Boeing Alert Service Bulletin 777-27A0125, dated February 3, 2023,
which is referred to in Boeing Alert Requirements Bulletin 777-
27A0125 RB, dated February 3, 2023.
(j) Exception to Requirements Bulletin Specifications
Where the Compliance Time column of the table in the
``Compliance'' paragraph of Boeing Alert Requirements Bulletin 777-
27A0125 RB, dated February 3, 2023, refers to the original issue
date of Requirements Bulletin 777-27A0125 RB, this AD requires using
the effective date of this AD.
(k) Parts Installation Prohibition
As of the effective date of this AD, no person may install a
transorb module, part numbers CLPT-12SP-06, CLPT-12SP-07, and CLPT-
12SP-67, on any airplane.
(l) 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
(m)(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.
(4) AMOCs approved for AD 2022-15-06 are approved as AMOCs for
the corresponding provisions of paragraph (g) of this AD.
(m) Related Information
(1) For more information about this AD, contact Raja
Vengadasalam, Aviation Safety Engineer, FAA, 2200 South 216th St.,
Des Moines, WA 98198; phone: 206-231-3859; email:
[email protected].
(2) Material identified in this AD that is not incorporated by
reference is available at the address specified in paragraph (n)(3)
of this AD.
(n) Material Incorporated by Reference
(1) The Director of the Federal Register approved the
incorporation by reference 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 the AD specifies otherwise.
(i) Boeing Alert Requirements Bulletin 777-27A0125 RB, dated
February 3, 2023.
(ii) [Reserved]
(3) For the 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.
(4) 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.
(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 October 7, 2025.
Lona C. Saccomando,
Acting Deputy Director, Integrated Certificate Management Division,
Aircraft Certification Service.
[FR Doc. 2025-21477 Filed 11-26-25; 8:45 am]
BILLING CODE 4910-13-P
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