Airworthiness Directives; The Boeing Company Airplanes

[Federal Register Volume 91, Number 124 (Tuesday, June 30, 2026)]
[Rules and Regulations]
[Pages 39418-39425]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2026-13206]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2026-7204; Project Identifier AD-2026-00548-T; 
Amendment 39-23396; AD 2026-13-13]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule; request for comments.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all 
The Boeing Company Model 737-, -200, -200C, -300, -400, -500, -600, -
700, -700C, -800, -900, and -900ER series airplanes, except for Model 
737-200 and -200C series airplanes equipped with a certain flight 
control system. This AD was prompted by the determination that radio 
altimeters cannot be relied upon to perform their intended function if 
they experience interference from wireless broadband operations in the 
3.7-3.98 GHz frequency band (5G Lower C-Band) while operating in 
Canadian airspace, and the determination that, during approach, 
landings, and go-arounds, as a result of this interference, certain 
airplane systems may not properly function, resulting in increased 
flightcrew workload while on approach with the flight director, 
autothrottle, or autopilot engaged, which could result in reduced 
ability of the flightcrew to maintain safe flight and landing of the 
airplane. This AD requires revising the existing airplane flight manual 
(AFM) to incorporate limitations prohibiting certain operations 
requiring radio altimeter data when operating in Canadian airspace. The 
FAA is issuing this AD to address the unsafe condition on these 
products.

DATES: This AD is effective July 1, 2026.
    The FAA must receive comments on this AD by August 14, 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 regulations.gov. 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 regulations.gov by 
searching for and locating Docket No. FAA-2026-7204; 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.

FOR FURTHER INFORMATION CONTACT: Ken Fairhurst, Continued Operational 
Safety Technical Advisor, FAA, 2200 South 216th St., Des Moines, WA 
98198; phone: 817-222-5390; email: [email protected].

SUPPLEMENTARY INFORMATION:

Comments Invited

    The FAA invites you to send any written data, views, or arguments 
about this final rule. Send your comments using a method listed under 
the ADDRESSES section. Include Docket No. FAA-2026-7204 and Project 
Identifier AD-2026-00548-T at the beginning of your comments. The most 
helpful comments reference a specific portion of the final rule, 
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 final rule 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

[[Page 39419]]

information you provide. The agency will also post a report summarizing 
each substantive verbal contact received about this final rule.

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 AD 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 AD, 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 AD. Submissions containing CBI should be sent to Ken 
Fairhurst, Continued Operational Safety Technical Advisor, FAA, 2200 
South 216th St., Des Moines, WA 98198; phone: 817-222-5390; email: 
[email protected]. Any commentary that the FAA receives that is 
not specifically designated as CBI will be placed in the public docket 
for this rulemaking.

Background

    The FAA issued AD 2021-23-12, Amendment 39-21810 (86 FR 69984, 
December 9, 2021) (AD 2021-23-12), for all transport and commuter 
category airplanes equipped with a radio altimeter. AD 2021-23-12 was 
prompted by a determination that radio altimeters cannot be relied upon 
to perform their intended function if they experience interference from 
wireless broadband operations in the 5G Lower C-Band, which is close to 
the frequency bands used by radio altimeters (4.2-4.4 GHz). AD 2021-23-
12 required revising the limitations section of the existing AFM to 
incorporate limitations prohibiting certain operations requiring radio 
altimeter data when in the presence of 5G Lower C-Band interference as 
identified by Notices to Air Missions (NOTAMs). The agency issued AD 
2021-23-12 because radio altimeter anomalies that are undetected by the 
automation or pilot, particularly close to the ground (e.g., landing 
flare), could lead to loss of continued safe flight and landing.
    The FAA subsequently identified an additional hazard presented by 
5G Lower C-Band interference on Boeing Model 737-100, -200, -200C, -
300, -400, -500, -600, -700, -700C, -800, -900, and -900ER series 
airplanes, except for Model 737-200 and -200C series airplanes equipped 
with an SP-77 flight control system, and issued AD 2022-05-04, 
Amendment 39-21955 (87 FR 10299, February 24, 2022) (AD 2022-05-04). AD 
2022-05-04 was prompted by the unsafe condition in AD 2021-23-12, as 
well as a determination that, during approach, landings, and go-
arounds, as a result of this interference, certain airplane systems may 
not properly function, resulting in increased flightcrew workload while 
on approach with the flight director, autothrottle, or autopilot 
engaged, which could result in reduced ability of the flightcrew to 
maintain safe flight and landing of the airplane. AD 2022-05-04 
required revising the limitations and operating procedures sections of 
the existing AFM to incorporate specific operating procedures for 
instrument landing system (ILS) approaches, speedbrake deployment, go-
arounds, and missed approaches, when in the presence of 5G Lower C-Band 
interference as identified by NOTAM.
    After the FAA issued AD 2021-23-12 and AD 2022-05-04, the agency 
determined that additional limitations were needed due to the continued 
deployment of new 5G Lower C-Band base stations whose signals were 
expected to cover most of the contiguous U.S., as well as the 
determination that radio altimeter anomalies could lead to increased 
flightcrew workload and flightcrew desensitization to warnings. 
Therefore, the FAA issued AD 2023-10-02, Amendment 39-22438 (88 FR 
34065, May 26, 2023) (AD 2023-10-02), to supersede AD 2021-23-12, and 
the FAA issued AD 2023-12-13, Amendment 39-22471 (88 FR 39996, June 21, 
2023) (AD 2023-12-13), to supersede AD 2022-05-04.
    Currently, AD 2023-12-13 requires revising the limitations section 
of the existing AFM to incorporate limitations for dispatch or release 
to airports, and approach, landing, and go-around on runways, in the 
entire contiguous U.S. airspace instead of only in areas identified by 
NOTAM; however, AD 2023-12-13 permits radio altimeter tolerant 
airplanes to perform these operations at 5G Lower C-Band mitigated 
airports as identified in an FAA Domestic Notice.

Actions Since AD 2023-12-13 Was Issued

    Since the FAA issued AD 2023-12-13, Transport Canada, which is the 
aviation authority for Canada, issued AD CF-2024-14, dated May 15, 2024 
(Transport Canada AD CF-2024-14), to correct an unsafe condition for 
all transport and commuter category airplanes with a radio altimeter. 
Transport Canada AD CF-2024-14 states that in July 2023, Innovation, 
Science and Economic Development Canada (ISED), Canada's spectrum 
regulator, published Standard Radio System Plans (SRSP)-520 Issue 3 \1\ 
and Radio Standard Specifications (RSS)-192 Issue 5,\2\ which define 
the spectrum environment for the 3.45-3.90 GHz frequency band in 
Canada. Transport Canada AD CF-2024-14 further states that spectrum 
auctions for the 3.45-3.65 GHz and the 3.65-3.9 GHz band were completed 
in 2021 and 2023, respectively.
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    \1\ https://ised-isde.canada.ca/site/spectrum-management-telecommunications/en/devices-and-equipment/standard-radio-system-plans/srsp-520-technical-requirements-fixed-andor-mobile-systems-including-flexible-use-broadband-systems.
    \2\ https://ised-isde.canada.ca/site/spectrum-management-telecommunications/en/devices-and-equipment/radio-equipment-standards/radio-standards-specifications-rss/rss-192-flexible-use-broadband-equipment-operating-band-3450-3900-mhz.
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    In July 2023, ISED implemented measures to mitigate Lower C-Band 
interference to radio altimeters, which provide the Canadian airspace 
greater protection from 5G Lower C-Band interference to radio 
altimeters as compared to the Lower C-Band environment in the 
contiguous U.S. airspace. These measures include exclusion and 
protection zones and airport effective isotropic radiated power (EIRP) 
elevation mask (a restriction that requires nearby cell tower signals 
to be angled downward so they do not interfere with aircraft 
altimeters) at certain airport runways covering the majority of air 
traffic in Canada, as well as nationwide reduced fundamental power 
emissions based on the degree of antenna uptilt above the horizon to 
minimize emissions from 5G base stations toward aircraft.
    In late March 2026, Transport Canada notified the FAA that, 
beginning July 1, 2026, changes in the 5G Lower C-Band protection 
mitigations established by ISED in 2023 would result in a more severe 
5G interference environment in the Canadian airspace. Exclusion and 
protection zones at airports will no longer exist and updates to the 
airport EIRP elevation mask, nationwide tilt restriction, emitter 
height limitation and reduced spurious emissions will only protect 
airplanes that are radio altimeter tolerant. The change in mitigations 
will result in an unsafe condition in the Canadian 5G interference 
environment.
    Transport Canada determined that radio altimeters cannot be relied 
upon to perform their intended function if they experience interference 
from

[[Page 39420]]

wireless broadband operations in the 3.45-3.98 GHz frequency band. 
Transport Canada based its determination on the same unsafe condition 
found by the FAA in AD 2023-10-02. As a result, Transport Canada AD CF-
2024-14 requires revising the limitations section of the existing AFM 
to incorporate limitations prohibiting certain operations requiring 
radio altimeter data, due to the presence of 5G Lower C-Band 
interference, while operating in Canadian airspace. As terminating 
action for the operating limitations, Transport Canada AD CF-2024-14 
provides that operators may upgrade their radio altimeters to 
demonstrate the tolerances for emissions as specified in Transport 
Canada AD CF-2024-14.
    Boeing subsequently conducted an analysis of the expected changes 
in the 5G Lower C-Band environment in Canada and the effects of 
interference with radio altimeters with respect to the Boeing fleet. In 
May 2026, Boeing reported that certain airplane configurations will not 
demonstrate tolerance to radio altimeter interference in the new 5G 
environment in Canada. Therefore, based on this information, the FAA 
determined that the unsafe condition identified in AD 2023-12-13 exists 
for Model 737-100, -200, -200C, -300, -400, -500, -600, -700, -700C, -
800, -900, and -900ER series airplanes, except for Model 737-200 and -
200C series airplanes equipped with an SP-77 flight control system, 
when operating in the Canadian airspace. As a result, operating 
limitations similar to the limitations required by AD 2023-12-13 are 
necessary.
    The FAA is issuing this AD to address the unsafe condition on these 
products.

FAA's Determination

    The FAA is issuing this AD because the agency has determined the 
unsafe condition described previously is likely to exist or develop in 
other products of the same type design.

AD Requirements

    For non-radio altimeter tolerant airplanes, this AD requires, 
before further flight in Canadian airspace, revising the existing AFM 
to incorporate limitations for dispatch or release to airports, and 
approach, landing, and go-around on runways when operating in Canadian 
airspace. This AD provides that modifying the airplane from a non-radio 
altimeter tolerant airplane to a radio altimeter tolerant airplane 
terminates the AFM operating limitations for that airplane.
    While AD 2023-12-13 also specifies limitations for dispatch or 
release to airports, and approach, landing, and go-around on runways 
for radio altimeter tolerant airplanes except at 5G Lower C-Band 
mitigated airports, this AD has no limitations for radio altimeter 
tolerant airplanes. The interference environment at Canadian airports 
after July 1, 2026, will be mitigated enough such that those 
limitations are not necessary for radio altimeter tolerant airplanes. 
The FAA also notes that most Model 737-100, -200, -200C, -300, -400, -
500, -600, -700, -700C, -800, -900, and -900ER series radio altimeter 
tolerant airplanes are not subject to the limitations in AD 2023-12-13 
under the provisions of an FAA-approved AMOC.
    An airplane that is a radio altimeter tolerant airplane using a 
method approved by the FAA for AD 2023-12-13 is also a radio altimeter 
tolerant airplane for the purposes of paragraph (g)(1) of this AD. 
Alternative methods of compliance (AMOC) listed in paragraph (j)(3) of 
this AD are approved for this AD.

Differences From Transport Canada AD CF-2024-14

    Transport Canada AD CF-2024-14 specifies the fundamental emissions 
are in the 3.45-3.98 GHz frequency band, while this AD specifies the 
3.7-3.98 GHz frequency band. AD 2023-10-02 and AD 2023-12-13 identified 
an unsafe condition from wireless broadband transmissions in the 3.7-
3.98 GHz frequency band, and this AD is based on that same 
determination. In addition, an airplane determined to be a radio 
altimeter tolerant airplane for the purposes of AD 2023-12-13, which 
has demonstrated the performance tolerances for fundamental emissions 
within the 3.7-3.98 GHz frequency band, would also be a radio altimeter 
tolerant airplane for purposes of this AD. Frequencies less than 3.7 
GHz are further away from the frequency bands used by radio altimeters 
(4.2 to 4.4 GHz), so an airplane determined to be tolerant in the range 
of 3.7-3.98 GHz is also tolerant to emissions less than 3.7 GHz.

Interim Action

    The FAA considers this AD to be an interim action. The FAA may 
consider further rulemaking if the Canadian 5G C-Band interference 
environment changes or if Canada issues an operational rule to address 
5G C-Band interference with radio altimeters.

Justification for Immediate Adoption and Determination of the Effective 
Date

    Section 553(b) of the Administrative Procedure Act (APA) (5 U.S.C. 
551 et seq.) authorizes agencies to dispense with notice and comment 
procedures for rules when the agency, for ``good cause,'' finds that 
those procedures are ``impracticable, unnecessary, or contrary to the 
public interest.'' Under this section, an agency, upon finding good 
cause, may issue a final rule without providing notice and seeking 
comment prior to issuance. Further, section 553(d) of the APA 
authorizes agencies to make rules effective in less than thirty days, 
upon a finding of good cause.
    An unsafe condition exists that requires the immediate adoption of 
this AD without providing an opportunity for public comments prior to 
adoption. The FAA has found that the risk to the flying public 
justifies forgoing notice and comment prior to adoption of this rule 
because radio altimeters cannot be relied upon to perform their 
intended function if they experience interference from wireless 
broadband operations in the 5G Lower C-Band. This interference may 
cause other airplane systems to not properly function, resulting in 
increased flightcrew workload while on approach with the flight 
director, autothrottle, or autopilot engaged, which could result in 
reduced ability of the flightcrew to maintain safe flight and landing 
of the airplane. The urgency is based on a change in the 5G Lower C-
Band environment in Canada, which is scheduled to occur on July 1, 
2026. Accordingly, notice and opportunity for prior public comment are 
impracticable and contrary to the public interest pursuant to 5 U.S.C. 
553(b).
    In addition, the FAA finds that good cause exists pursuant to 5 
U.S.C. 553(d) for making this amendment effective in less than 30 days, 
for the same reasons the FAA found good cause to forgo notice and 
comment.

Regulatory Flexibility Act

    The requirements of the Regulatory Flexibility Act (RFA) do not 
apply when an agency finds good cause pursuant to 5 U.S.C. 553 to adopt 
a rule without prior notice and comment. Because the FAA has determined 
that it has good cause to adopt this rule without notice and comment, 
RFA analysis is not required.

Costs of Compliance

    The FAA notes that since operators must comply with this AD before 
further flight in Canadian airspace, airplanes that do not operate in 
Canada will not have to comply and therefore will have no costs under 
this AD.

[[Page 39421]]

    The FAA estimates that this AD affects 1,995 airplanes of U.S. 
registry. The FAA expects that many of the affected airplanes have 
upgraded radio altimeters; therefore, the FAA estimates the total 
number of airplanes affected by this AD to be less than the total fleet 
size provided in this AD. The FAA estimates the following costs to 
comply with this AD:

                                                 Estimated Costs
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                                                                              Cost per          Cost on U.S.
              Action                      Labor cost         Parts cost        product           operators
----------------------------------------------------------------------------------------------------------------
AFM revision for non-RAT airplanes  1 work-hour x $85 per              $0             $85  Up to $169,575.
                                     hour = $85.
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                                      Estimated Costs for Optional Actions
----------------------------------------------------------------------------------------------------------------
                Action                        Labor cost               Parts cost            Cost per product
----------------------------------------------------------------------------------------------------------------
Modification (radio altimeter          .......................  .......................  Up to $120,000
 replacement option).                                                                     (includes parts and
                                                                                          labor).
Modification (filter addition option)  24 work-hours x $85 per  $12,000 per filter.....  Up to $14,040 (includes
                                        hour = $2,040 per                                 parts and labor).
                                        filter.
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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 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, and
    (2) Will not affect intrastate aviation in Alaska.

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 adding the following new airworthiness 
directive:

2026-13-13 The Boeing Company: Amendment 39-23396; Docket No. FAA-
2026-7204; Project Identifier AD-2026-00548-T.

(a) Effective Date

    This airworthiness directive (AD) is effective July 1, 2026.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to all The Boeing Company Model 737-100, -200, -
200C, -300, -400, -500, -600, -700, -700C, -800, -900, and -900ER 
series airplanes, certificated in any category, except for Model 
737-200 and -200C series airplanes equipped with an SP-77 flight 
control system.

(d) Subject

    Air Transport Association (ATA) of America Code 34, Navigation.

(e) Unsafe Condition

    This AD was prompted by the determination that radio altimeters 
cannot be relied upon to perform their intended function if they 
experience interference from wireless broadband operations in the 
3.7-3.98 GHz frequency band (5G Lower C-Band) when operating in 
Canadian airspace, and a determination that, during approach, 
landings, and go-arounds, as a result of this interference, certain 
airplane systems may not properly function, resulting in increased 
flightcrew workload while on approach with the flight director, 
autothrottle, or autopilot engaged. The FAA is issuing this AD to 
address 5G Lower C-Band interference that could result in increased 
flightcrew workload and could lead to reduced ability of the 
flightcrew to maintain safe flight and landing of the airplane.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Definitions

    (1) For purposes of this AD, a ``radio altimeter tolerant 
airplane'' is one for which the radio altimeter, as installed, 
demonstrates the tolerances specified in paragraphs (g)(1)(i) and 
(ii) of this AD, using a method approved by the FAA. No actions are 
required by this AD for radio altimeter tolerant airplanes.
    (i) Tolerance to radio altimeter interference, for the 
fundamental emissions (3.7-3.98 GHz), at or above the power spectral 
density (PSD) curve threshold specified in figure 1 to paragraph 
(g)(1)(i) of this AD.
BILLING CODE 4910-13-P

Figure 1 to Paragraph (g)(1)(i)--Fundamental Effective Isotropic PSD at 
Outside Interface of Aircraft Antenna

[[Page 39422]]

[GRAPHIC] [TIFF OMITTED] TR30JN26.033

    (ii) Tolerance to radio altimeter interference, for the spurious 
emissions (4.2-4.4 GHz), at or above the PSD curve threshold 
specified in figure 2 to paragraph (g)(1)(ii) of this AD.

Figure 2 to Paragraph (g)(1)(ii)--Spurious Effective Isotropic PSD at 
Outside Interface of Aircraft Antenna

[[Page 39423]]

[GRAPHIC] [TIFF OMITTED] TR30JN26.034

    (2) For purposes of this AD, a ``non-radio altimeter tolerant 
airplane'' is one for which the radio altimeter, as installed, does 
not demonstrate the tolerances specified in paragraphs (g)(1)(i) and 
(ii) of this AD.

(h) Airplane Flight Manual (AFM) Revision

    For non-radio altimeter tolerant airplanes: Before further 
flight in Canadian airspace, do the actions specified in paragraphs 
(h)(1) and (2) of this AD.
    (1) Revise the Limitations Section of the existing AFM to 
include the information specified in figure 3 to paragraph (h)(1) of 
this AD. This may be done by inserting a copy of figure 3 to 
paragraph (h)(1) of this AD into the existing AFM.

Figure 3 to Paragraph (h)(1)--AFM Limitations Revision for Non-Radio 
Altimeter Tolerant Airplanes in Canadian Airspace

[[Page 39424]]

[GRAPHIC] [TIFF OMITTED] TR30JN26.035

    (2) Revise the Operating Procedures Section of the existing AFM 
to include the information specified in figure 4 to paragraph (h)(2) 
of this AD or figure 5 to paragraph (h)(2) of this AD, as 
applicable. This may be done by inserting a copy of figure 4 to 
paragraph (h)(2) of this AD or figure 5 to paragraph (h)(2) of this 
AD, as applicable, into the Operating Procedures Section of the 
existing AFM. An AFM with an Operating Procedures Section that 
complies with paragraph (k)(1) of AD 2023-12-13, Amendment 39-22471 
(88 FR 39996, June 21, 2023) is acceptable for compliance with the 
requirements of this paragraph of this AD.

Figure 4 to Paragraph (h)(2)--AFM Operating Procedures Revision for 
Model 737-100, -200, -200C, -300, -400, and -500 Series Airplanes
[GRAPHIC] [TIFF OMITTED] TR30JN26.036

Figure 5 to Paragraph (h)(2)--AFM Operating Procedures Revision for 
Model 737-600, -700, -700C, -800, -900, and -900ER Series Airplanes

[[Page 39425]]

[GRAPHIC] [TIFF OMITTED] TR30JN26.037

BILLING CODE 4910-13-C

(i) Terminating Action for AFM Revision

    (1) Modifying the airplane from a non-radio altimeter tolerant 
airplane to a radio altimeter tolerant airplane terminates the 
limitations in paragraph (h)(1) of this AD and the operating 
procedures in paragraph (h)(2) of this AD for that airplane.
    (2) After modifying the airplane to a radio altimeter tolerant 
airplane, the limitations in paragraph (h)(1) of this AD and the 
operating procedures in paragraph (h)(2) of this AD may be removed 
from the AFM.

(j) 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 AIR-520, Continued 
Operational Safety Branch, send it to the attention of the person 
identified in paragraph (k) of this AD and email 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) The following AMOCs approved previously for AD 2023-12-13, 
Amendment 39-22471 (88 FR 39996, June 21, 2023) are approved as 
AMOCs for paragraph (g)(1) of this AD: FAA AMOC letters 720-23-
00137, 720-23-00138, 720-23-00158, 720-23-00169, 720-25-00025, 720-
25-00031, and 720-26-00009.

(k) Additional Information

    For more information about this AD, contact Ken Fairhurst, 
Continued Operational Safety Technical Advisor, FAA, 2200 South 
216th St., Des Moines, WA 98198; phone: 817-222-5390; email: 
[email protected].

(l) Material Incorporated by Reference

    None.

    Issued on June 25, 2026.
Brian Knaup,
Acting Deputy Director, Integrated Certificate Management Division, 
Aircraft Certification Service.
[FR Doc. 2026-13206 Filed 6-26-26; 4:15 pm]
BILLING CODE 4910-13-P

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