Airworthiness Directives; Pilatus Aircraft Ltd

Issuing agencies

Abstract

The FAA proposes to supersede Airworthiness Directive (AD) 2025-20-02, which applies to all Pilatus Aircraft Ltd. (Pilatus) Model PC-24 airplanes. AD 2025-20-02 requires incorporating a temporary revision into the existing airplane flight manual (AFM) for the affected airplanes, which revises the Abnormal Procedures Section. That action was considered an interim action. Since the FAA issued AD 2025- 20-02, updated software has been developed and instructions have been issued for installing the software. In addition, revised operational instructions have been issued that are applicable after installation of the updated software. This proposed AD would require installing the updated software and incorporating the applicable revised operational instructions into the AFM. 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 212 (Wednesday, November 4, 2026)</title>
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[Federal Register Volume 91, Number 212 (Wednesday, November 4, 2026)]
[Proposed Rules]
[Pages 69506-69508]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2026-22496]


========================================================================
Proposed Rules
                                                Federal Register
________________________________________________________________________

This section of the FEDERAL REGISTER contains notices to the public of 
the proposed issuance of rules and regulations. The purpose of these 
notices is to give interested persons an opportunity to participate in 
the rule making prior to the adoption of the final rules.

========================================================================


Federal Register / Vol. 91, No. 212 / Wednesday, November 4, 2026 / 
Proposed Rules

[[Page 69506]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2026-13798; Project Identifier MCAI-2026-00797-A]
RIN 2120-AA64


Airworthiness Directives; Pilatus Aircraft Ltd

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: The FAA proposes to supersede Airworthiness Directive (AD) 
2025-20-02, which applies to all Pilatus Aircraft Ltd. (Pilatus) Model 
PC-24 airplanes. AD 2025-20-02 requires incorporating a temporary 
revision into the existing airplane flight manual (AFM) for the 
affected airplanes, which revises the Abnormal Procedures Section. That 
action was considered an interim action. Since the FAA issued AD 2025-
20-02, updated software has been developed and instructions have been 
issued for installing the software. In addition, revised operational 
instructions have been issued that are applicable after installation of 
the updated software. This proposed AD would require installing the 
updated software and incorporating the applicable revised operational 
instructions into the AFM. 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 December 
21, 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-2026-13798; 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, the mandatory continuing airworthiness 
information (MCAI) any comments received, and other information. The 
street address for Docket Operations is listed above.
    Material Incorporated by Reference:
    <bullet> For European Union Aviation Safety Agency (EASA) material 
identified in this NPRM, contact EASA, Konrad-Adenauer-Ufer 3, 50668 
Cologne, Germany; phone: +49 221 8999 000; email: <a href="/cdn-cgi/l/email-protection#89c8cdfac9ece8fae8a7ecfcfbe6f9e8a7ecfc"><span class="__cf_email__" data-cfemail="c08184b380a5a1b3a1eea5b5b2afb0a1eea5b5">[email&#160;protected]</span></a>; 
website: easa.europa.eu. You may find this material on the EASA website 
at ad.easa.europa.eu.
    <bullet> You may view this material at the FAA, Airworthiness 
Products Section, Operational Safety Branch, 1100 Main, Kansas City, MO 
64105. For information on the availability of this material at the FAA, 
call (817) 222-5110.

FOR FURTHER INFORMATION CONTACT: Doug Rudolph, Aviation Safety 
Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; 
phone: (816) 329-4059; email: <a href="/cdn-cgi/l/email-protection#acc8c3d9cb82ded9c8c3c0dcc4eccacdcd82cbc3da"><span class="__cf_email__" data-cfemail="51353e24367f2324353e3d2139113730307f363e27">[email&#160;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 ADDRESSES. Include ``Docket No. FAA-2026-13798; Project 
Identifier MCAI-2026-00797-A'' 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 the 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.

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 Doug 
Rudolph, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, 
Westbury, NY 11590. Any commentary that the FAA receives which is not 
specifically designated as CBI will be placed in the public docket for 
this rulemaking.

Background

    The FAA issued AD 2025-20-02, Amendment 39-23155 (90 FR 53208, 
November 25, 2025) (AD 2025-20-02), for all Pilatus Model PC-24 
airplanes. AD 2025-20-02 was prompted by EASA AD 2024-0240, dated 
December 10, 2024 (EASA AD 2024-0240), issued by EASA, which is the 
Technical Agent for the Member States of the European Union. EASA 
issued EASA AD 2024-0240, dated December 10, 2024 (EASA AD 2024-0240), 
to address an unsafe condition identified as an occurrence of an 
inaccurate flight director calculation on approach. The MCAI stated 
that heading splits can cause errors in the flight director 
calculations, which results in lateral offsets to the desired approach 
course. The FAA issued AD 2025-20-02 as an interim action to address 
the unsafe condition described above.
    AD 2025-20-02 requires incorporating a temporary revision into the 
existing AFM for the affected

[[Page 69507]]

airplanes, which revises the Abnormal Procedures Section.

Actions Since AD 2025-20-02 Was Issued

    Since the FAA issued AD 2025-20-02, EASA superseded EASA AD 2024-
0240 and issued EASA AD 2026-0149, dated July 28, 2026 (EASA AD 2026-
0149) (also referred to as the MCAI). The MCAI states that, since EASA 
AD 2024-0240 was issued, Pilatus developed Primus APEX DFZ Build 6.0 
software and issued service information providing instructions for 
installing the software. Pilatus also issued AFM-TR 02371-081, which 
provides operational instructions applicable after installation of 
Primus APEX DFZ Build 6.0 software.
    The MCAI retains the requirement to incorporate the existing AFM 
instructions and adds requirements to install the updated software and, 
after installation of the updated software, incorporate the revised 
operational instructions into the AFM. The FAA is issuing this AD to 
prevent heading splits that can cause errors in flight director 
calculations, resulting in lateral offsets to the desired approach 
course. The unsafe condition, if not addressed, could result in an 
increased pilot workload and a reduction of the safety margins.
    You may examine the MCAI in the AD docket at <a href="http://regulations.gov">regulations.gov</a> under 
Docket No. FAA-2026-13798.

Material Incorporated by Reference Under 1 CFR Part 51

    The FAA reviewed EASA AD 2026-0149, which specifies procedures for 
installing Primus APEX DFZ Build 6.0 software and, after installation 
of the software, incorporating Pilatus PC-24 AFM-TR 02371-081 into the 
AFM. AFM-TR 02371-081 provides operational instructions applicable 
after installation of Primus APEX DFZ Build 6.0 software. EASA AD 2026-
0149 also allows incorporation of a later AFM revision that includes 
the applicable AFM instructions.
    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.

FAA's Determination

    These products have been approved by the civil aviation authority 
(CAA) of another country and are approved for operation in the United 
States. Pursuant to the FAA's bilateral agreement with this State of 
Design Authority, that authority has notified the FAA of the unsafe 
condition described in the MCAI referenced above. 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.

Proposed AD Requirements in This NPRM

    This proposed AD would require accomplishing the actions specified 
in the MCAI, described previously, as incorporated by reference, except 
for any differences identified as exceptions in the regulatory text of 
this proposed AD.
    The owner or operator (pilot) holding at least a private pilot 
certificate may revise the existing AFM for the airplane as specified 
in paragraphs (h)(3) and (4) of this proposed AD and must enter 
compliance with the applicable paragraph of this proposed AD into the 
airplane maintenance records in accordance with 14 CFR 43.9(a) and 
91.417(a)(2)(v). The pilot may perform these actions because they only 
involve revising the AFM. These actions could be performed equally well 
by a pilot or a mechanic. This is an exception to the FAA's standard 
maintenance regulations.

Explanation of Required Compliance Information

    In the FAA's ongoing efforts to improve the efficiency of the AD 
process, the FAA developed a process to use some CAA ADs as the primary 
source of information for compliance with requirements for 
corresponding FAA ADs. The FAA has been coordinating this process with 
manufacturers and CAAs. As a result, the FAA proposes to incorporate 
EASA AD 2026-0149 by reference in the FAA final rule. This proposed AD 
would, therefore, require compliance with EASA AD 2026-0149 in its 
entirety through that incorporation, except for any differences 
identified as exceptions in the regulatory text of this proposed AD. 
Using common terms that are the same as the heading of a particular 
section in EASA AD 2026-0149 does not mean that operators need comply 
only with that section. For example, where the AD requirement refers to 
``all required actions and compliance times,'' compliance with this AD 
requirement is not limited to the section titled ``Required Action(s) 
and Compliance Time(s)'' in EASA AD 2026-0149. Material required by 
EASA AD 2026-0149 for compliance will be available at <a href="http://regulations.gov">regulations.gov</a> 
under Docket No FAA-2026-13798 after the FAA final rule is published.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 150 airplanes of U.S. registry.
    The FAA estimates the following costs to comply with this proposed 
AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                 Cost on U.S.
              Action                    Labor cost          Parts cost     Cost per product       operators
----------------------------------------------------------------------------------------------------------------
Revise AFM.......................  1 work-hour x $85                   $0               $85              $12,750
                                    per hour = $85.
Install Primus APEX DFZ Build 6.0  4 work-hours x $85               1,000             1,340              201,000
 software and incorporate AFM-TR    per hour = $340.
 02371-081 after software
 installation.
----------------------------------------------------------------------------------------------------------------

    The FAA has included all known costs in its cost estimate. 
According to the manufacturer, however, some of the costs of this 
proposed 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.

[[Page 69508]]

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 that the 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:
0
a. Removing Airworthiness Directive 2025-20-02, Amendment 39-23155 (90 
FR 53208, November 25, 2025); and
0
b. Adding the following new airworthiness directive:

Pilatus Aircraft Ltd: Docket No. FAA-2026-13798; Project Identifier 
MCAI-2026-00797-A.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by December 21, 2026.

(b) Affected ADs

    This AD replaces AD 2025-20-02, Amendment 39-23155 (90 FR 53208, 
November 25, 2025).

(c) Applicability

    This AD applies to Pilatus Aircraft Ltd. Model PC-24 airplanes, 
certificated in any category, as identified in European Union 
Aviation Safety Agency AD 2026-0149, dated July 28, 2026 (EASA AD 
2026-0149).

(d) Subject

    Joint Aircraft System Component (JASC) Code 3400, Navigation 
System.

(e) Unsafe Condition

    This AD was prompted by an occurrence of an inaccurate flight 
director calculation on approach. The FAA is issuing this AD to 
prevent heading splits that can cause errors in flight director 
calculations, resulting in lateral offsets to the desired approach 
course. The unsafe condition, if not addressed, could result in an 
increased pilot workload and a reduction of the safety margins.

(f) Compliance

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

(g) Required Actions

    (1) Except as specified in paragraph (h) of this AD: Comply with 
all required actions and compliance times specified in, and in 
accordance with, EASA AD 2026-0149.
    (2) The AFM revisions required by this AD may be performed by 
the owner or operator (pilot) holding at least a private pilot 
certificate and must be entered into the aircraft records showing 
compliance with this AD in accordance with 14 CFR 43.9(a) and 
91.417(a)(2)(v). The record must be maintained as required by 14 CFR 
91.417, 121.380, or 135.439.

(h) Exceptions to EASA AD 2026-0149

    (1) Where EASA AD 2026-0149 refers to its effective date, this 
AD requires using the effective date of this AD.
    (2) Where EASA AD 2026-0149 refers to December 24, 2024 (the 
effective date of EASA AD 2024-0240), this AD requires using 
December 30, 2025 (the effective date of AD 2025-20-02).
    (3) Where paragraph (1) of EASA AD 2026-0149 specifies to 
``implement the instructions of AFM-TR 02371-075'', this AD requires 
replacing that text with ``revise the Abnormal Procedures Section of 
the existing AFM for your airplane by inserting a copy of AFM-TR 
02371-075''.
    (4) Where paragraph (5) of EASA AD 2026-0149 specifies to 
``implement the instructions of AFM-TR 02371-081'', this AD requires 
replacing that text with ``revise the Normal Procedures Section of 
the existing AFM for your airplane by inserting a copy of AFM-TR 
02371-081''.
    (5) This AD does not adopt the ``Remarks'' section of EASA AD 
2026-0149.

(i) No Reporting Requirement

    Although the material referenced in EASA AD 2026-0149 specifies 
to submit certain information to the manufacturer, this AD does not 
include that requirement.

(j) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, International Validation 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 local Flight 
Standards District Office, as appropriate. If sending information 
directly to the manager of the International Validation Branch, send 
it to the attention of the person identified in paragraph (k) of 
this AD and email to <a href="/cdn-cgi/l/email-protection#7435393b37341215155a131b02"><span class="__cf_email__" data-cfemail="ebaaa6a4a8ab8d8a8ac58c849d">[email&#160;protected]</span></a>.
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the local flight standards district office/certificate holding 
district office.

(k) Additional Information

    For more information about this AD, contact Doug Rudolph, 
Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, 
Westbury, NY 11590; phone: (816) 329-4059; email: 
<a href="/cdn-cgi/l/email-protection#89ede6fceea7fbfcede6e5f9e1c9efe8e8a7eee6ff"><span class="__cf_email__" data-cfemail="3d5952485a134f485952514d557d5b5c5c135a524b">[email&#160;protected]</span></a>.

(l) 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) European Union Aviation Safety Agency (EASA) AD 2026-0149, 
dated July 28, 2026.
    (ii) [Reserved]
    (3) For EASA material identified in this AD, contact EASA, 
Konrad-Adenauer-Ufer 3, 50668 Cologne, Germany; phone: +49 221 8999 
000; email: <a href="/cdn-cgi/l/email-protection#ecada89fac898d9f8dc289999e839c8dc28999"><span class="__cf_email__" data-cfemail="7233360132171301135c1707001d02135c1707">[email&#160;protected]</span></a>; website: easa.europa.eu. You may 
find this EASA AD on the EASA website at ad.easa.europa.eu.
    (4) You may view this material at the FAA, Airworthiness 
Products Section, Operational Safety Branch, 1100 Main, Kansas City, 
MO 64105. For information on the availability of this material at 
the FAA, call (817) 222-5110.
    (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#fd9b8fd394938e8d989e89949293bd939c8f9cd39a928b"><span class="__cf_email__" data-cfemail="b0d6c29ed9dec3c0d5d3c4d9dfdef0ded1c2d19ed7dfc6">[email&#160;protected]</span></a>.

    Issued on November 2, 2026.
Steven W. Thompson,
Acting Deputy Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2026-22496 Filed 11-3-26; 8:45 am]
BILLING CODE 4910-13-P


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