Proposed Rule2026-02420
Airworthiness Directives; The Boeing Company Airplanes
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
February 6, 2026
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
The FAA proposes to adopt a new airworthiness directive (AD) for all The Boeing Company Model 777-200, -200LR, -300, and -300ER series airplanes. This proposed AD was prompted by a report of corrosion found on a satellite communications (SATCOM) high gain antenna adapter plate. This proposed AD would require repetitive inspections for corrosion of the SATCOM high gain antenna adapter plate and applicable on-condition actions. The FAA is proposing this AD to address the unsafe condition on these products.
Full Text
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<title>Federal Register, Volume 91 Issue 25 (Friday, February 6, 2026)</title>
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[Federal Register Volume 91, Number 25 (Friday, February 6, 2026)]
[Proposed Rules]
[Pages 5384-5386]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2026-02420]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2026-0741; Project Identifier AD-2025-00817-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 777-200, -200LR, -300, and -300ER
series airplanes. This proposed AD was prompted by a report of
corrosion found on a satellite communications (SATCOM) high gain
antenna adapter plate. This proposed AD would require repetitive
inspections for corrosion of the SATCOM high gain antenna adapter plate
and applicable on-condition actions. 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 23,
2026.
ADDRESSES: You may send comments, using the procedures found in 14 CFR
11.43 and 11.45, by any of the following methods:
<bullet> Federal eRulemaking Portal: Go to <a href="http://regulations.gov">regulations.gov</a>. Follow
the instructions for submitting comments.
<bullet> Fax: 202-493-2251.
<bullet> 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.
<bullet> 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 <a href="http://regulations.gov">regulations.gov</a> under
Docket No. FAA-2026-0741; 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:
<bullet> For Boeing material identified in this proposed 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 <a href="http://myboeingfleet.com">myboeingfleet.com</a>.
<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 <a href="http://regulations.gov">regulations.gov</a> under
Docket No. FAA-2026-0741.
FOR FURTHER INFORMATION CONTACT: Stefanie Roesli, Aviation Safety
Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 206-
231-3964; email: <a href="/cdn-cgi/l/email-protection#5d2e29383b3c3334387333732f32382e31341d3b3c3c733a322b"><span class="__cf_email__" data-cfemail="1467607172757a7d713a7a3a667b7167787d547275753a737b62">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION:
Comments Invited
The FAA invites you to send any written relevant data, views, or
arguments about this proposal. Send your comments using a method listed
under the ADDRESSES section. Include ``Docket No. FAA-2026-0741;
Project Identifier AD-2025-00817-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
<a href="http://regulations.gov">regulations.gov</a>, including any personal information you provide. The
agency will also post a report summarizing each substantive verbal
contact received about this NPRM.
[[Page 5385]]
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
Stefanie Roesli, Aviation Safety Engineer, FAA, 2200 South 216th St.,
Des Moines, WA 98198; phone: 206-231-3964; email:
<a href="/cdn-cgi/l/email-protection#f68582939097989f93d898d8849993859a9fb6909797d8919980"><span class="__cf_email__" data-cfemail="3043445556515e59551e5e1e425f55435c59705651511e575f46">[email protected]</span></a>. 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 indicating that during a heavy
maintenance check on a Model 767 airplane, corrosion was found on a
certain SATCOM high gain antenna adapter plate. The most severe
corrosion was found at the nutplates around the edge of the adapter
plate; the nutplates are used to fasten the antenna assembly to the
adapter plate. Corrosion was also found at the adapter plate mounting
lugs and the area around the bonding strap that is connected between
the adapter plate and the airplane skin. Contributing factors that lead
to an increase in risk of a parts departing airplane (PDA) event
include a lack of nutplate or nutplate recess corrosion protection,
lack of instructions for re-application of primer and paint, lack of
maintenance inspections and repair procedures, and moisture protection
appears to be inadequate for the environment. Undetected corrosion of
the adapter plate could lead to a PDA event. A PDA event of the SATCOM
high gain antenna adapter system could damage the primary flight
control surfaces, which could result in loss of continued safe flight
and landing.
The SATCOM high gain antenna for Model 777 airplane has a similar
adapter plate to the one installed on Model 767 airplanes. In related
rulemaking, the FAA issued an NPRM, Docket No. FAA-2025-0741 (90 FR
17741), to address the unsafe condition on Model 767 airplanes.
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.
Material Incorporated by Reference Under 1 CFR Part 51
The FAA reviewed Boeing Alert Requirements Bulletin 777-23A0454 RB,
dated May 16, 2025. This material specifies procedures for repetitive
detailed inspections for corrosion of the SATCOM high gain antenna
adapter plate and applicable on-condition actions. On-condition actions
include repairing the SATCOM high gain antenna adapter plate or
replacing it with a new or serviceable SATCOM high gain antenna adapter
plate if any corrosion found is less than or equal to 0.005 inch in
depth; and replacing the SATCOM high gain antenna adapter plate with a
new or serviceable SATCOM high gain antenna adapter plate if any
corrosion found is greater than 0.005 inch in depth. 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.
Proposed AD Requirements in This NPRM
This proposed AD would require accomplishing the actions specified
in the material 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
material at <a href="http://regulations.gov">regulations.gov</a> under Docket No. FAA-2026-0741.
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would
affect 238 airplanes of U.S. registry. The FAA estimates the following
costs to comply with this proposed AD:
Estimated Costs
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Cost on U.S.
Action Labor cost Parts cost Cost per product operators
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Detailed inspection............ 11 work-hours x None................. $935 per $222,530 per
$85 per hour = inspection cycle. inspection
$935 per cycle.
inspection cycle.
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The FAA estimates the following costs to do any necessary repairs
or replacements that would be required based on the results of the
proposed inspection. The agency has no way of determining the number of
aircraft that might need these repairs or replacements:
On-Condition Costs
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Cost per
Action Labor cost Parts cost product
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Repair of adapter plate............... 5 work-hours x $85 per Negligible................... $425
hour = $425.
Replacement of adapter plate.......... 2 work-hour x $85 per $18,000...................... 18,170
hour = $170.
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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
[[Page 5386]]
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 adding the following new airworthiness
directive:
The Boeing Company: Docket No. FAA-2026-0741; Project Identifier AD-
2025-00817-T.
(a) Comments Due Date
The FAA must receive comments on this airworthiness directive
(AD) by March 23, 2026.
(b) Affected ADs
None.
(c) Applicability
This AD applies to all The Boeing Company Model 777-200, -200LR,
-300, and -300ER series airplanes, certificated in any category.
(d) Subject
Air Transport Association (ATA) of America Code 23,
Communications.
(e) Unsafe Condition
This AD was prompted by a report of corrosion found on a
satellite communications (SATCOM) high gain antenna adapter plate.
The FAA is issuing this AD to address corrosion of the adapter
plate, which could lead to a part departing airplane (PDA). A PDA
event of the SATCOM high gain antenna adapter system could damage
the primary flight control surfaces, which could result in loss of
continued safe flight and landing.
(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 777-23A0454 RB, dated May 16, 2025, do
all applicable actions identified in, and in accordance with, the
Accomplishment Instructions of Boeing Alert Requirements Bulletin
777-23A0454 RB, dated May 16, 2025.
Note 1 to paragraph (g): Guidance for accomplishing the actions
required by this AD can be found in Boeing Alert Service Bulletin
777-23A0454, dated May 16, 2025, which is referred to in Boeing
Alert Requirements Bulletin 777-23A0454 RB, dated May 16, 2025.
(h) Exception to Requirements Bulletin Specifications
Where the Condition and Boeing Recommended Compliance Time
columns of the tables in the ``Compliance'' paragraph of Boeing
Alert Requirements Bulletin 777-23A0454 RB, dated May 16, 2025,
refer to the original issue date of Requirements Bulletin 777-
23A0454 RB, this AD requires using the effective date 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 Continued Operational
Safety Branch, send it to the attention of the person identified in
paragraph (j) of this AD. Information may be emailed to:
<a href="/cdn-cgi/l/email-protection#a9e8e4e6eae9cfc8c887cec6df"><span class="__cf_email__" data-cfemail="03424e4c40436562622d646c75">[email protected]</span></a>. Before using any approved AMOC, notify your
appropriate principal inspector, or lacking a principal inspector,
the manager of the responsible Flight Standards Office.
(2) 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
For more information about this AD, contact Stefanie Roesli,
Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA
98198; phone: 206-231-3964; email: <a href="/cdn-cgi/l/email-protection#0b787f6e6d6a65626e25652579646e7867624b6d6a6a256c647d"><span class="__cf_email__" data-cfemail="deadaabbb8bfb0b7bbf0b0f0acb1bbadb2b79eb8bfbff0b9b1a8">[email protected]</span></a>.
(k) 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 777-23A0454 RB, dated May
16, 2025.
(ii) [Reserved]
(3) 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 <a href="http://myboeingfleet.com">myboeingfleet.com</a>.
(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 <a href="http://www.archives.gov/federal-register/cfr/ibr-locations">www.archives.gov/federal-register/cfr/ibr-locations</a> or email <a href="/cdn-cgi/l/email-protection#1274603c7b7c61627771667b7d7c527c7360733c757d64"><span class="__cf_email__" data-cfemail="dbbda9f5b2b5a8abbeb8afb2b4b59bb5baa9baf5bcb4ad">[email protected]</span></a>.
Issued on January 29, 2026.
Peter A. White,
Deputy Director, Integrated Certificate Management Division, Aircraft
Certification Service.
[FR Doc. 2026-02420 Filed 2-5-26; 8:45 am]
BILLING CODE 4910-13-P
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