Proposed Rule

Airworthiness Directives; Pilatus Aircraft Ltd. Airplanes

A Proposed Rule by the Federal Aviation Administration on 03/19/2026

• This document has a comment period that ends in 46 days.
  (05/04/2026) View Comment Instructions

• PDF

• Document Details

• Document Dates

- Table of Contents

• Public Comments
• Regulations.gov Data

- Sharing

• Print
• Other Formats
• Public Inspection Published Document: 2026-05364 (91 FR 13240) Document Headings ###### Department of Transportation

Federal Aviation Administration

1. 14 CFR Part 39
2. [Docket No. FAA-2026-2715; Project Identifier MCAI-2025-01779-A]
3. RIN 2120-AA64

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for certain Pilatus Aircraft Ltd. (Pilatus) Model PC-12/47E airplanes. This AD was prompted by a report of the stall warning protection system (SWPS) engaging when not appropriate. This proposed AD would require updating operational software and incorporating a pilot's operating handbook (POH) temporary revision. The proposed AD would also prohibit the installation of affected software. The FAA is proposing this AD to address the unsafe condition on these products.

DATES:

The FAA must receive comments on this NPRM by May 4, 2026.

ADDRESSES:

You may send comments, using the procedures found in 14 CFR 11.43 and 11.45, by any of the following methods:

• Federal eRulemaking Portal: Go to regulations.gov. Follow the instructions for submitting comments.
• Fax: (202) 493-2251.
• 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.
• 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 under Docket No. FAA-2026-2715; 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. ( printed page 13241)

Material Incorporated by Reference:

• For European Union Aviation Agency (EASA) material identified in this NPRM, contact EASA, Konrad-Adenauer-Ufer 3, 50668 Cologne, Germany; phone: +49 221 8999 000; email: ADs@easa.europa.eu; website: easa.europa.eu. You may find this material on the EASA website at ad.easa.europa.eu.
• You may view this material at the FAA, Airworthiness Products Section, Operational Safety Branch, 901 Locust, Kansas City, MO 64106. 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: doug.rudolph@faa.gov.

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-2026-2715; Project Identifier MCAI-2025-01779-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 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 regulations.gov, 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

EASA, which is the Technical Agent for the Member States of the European Union, has issued EASA AD 2025-0271, dated December 2, 2025 (EASA AD 2025-0271) (also referred to as the MCAI), to correct an unsafe condition on certain Pilatus Model PC-12/47E airplanes. The MCAI states that during a test flight on a Pilatus Model PC-12/47E airplane in which the airplane flew specific maneuvers where gravitational loads (g-loads) were close to 0 g, during landing the SWPS triggered at a higher-than-expected airspeed. The SWPS included the aural warning, stick shaker, and stick pusher. This same software is on the delivered airplanes that are affected by this AD.

This condition, if not addressed, could result in reduced safety margins of the airplane, increased pilot workload, and reduced control of the airplane.

You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA-2026-2715.

Material Incorporated by Reference Under 1 CFR Part 51

The FAA reviewed EASA AD 2025-0271, which specifies procedures for updating the Honeywell Primus Apex operational software, and for incorporating Pilatus PC-12/47E POH Temporary Revision (TR) No. 32 (also referred to as POH-TR 32) into the POH. EASA AD 2025-0271 also allows for the incorporation of a later POH revision that includes the same POH amendment content and prohibits the installation of affected software. 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, except for any differences identified as exceptions in the regulatory text of this proposed AD. The owner/operator (pilot) holding at least a private pilot certificate may revise the existing POH for the airplane 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 this action because it only involves revising the POH. This action 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 2025-0271 by reference in the FAA final rule. This proposed AD would, therefore, require compliance with EASA AD 2025-0271 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 the EASA AD 2025-0271 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 2025-0271. Material required by EASA AD 2025-0271 for compliance will be available at regulations.gov under Docket No. FAA-2026-2715 after the FAA final rule is published. ( printed page 13242)

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would affect 265 airplanes of U.S. registry.

The FAA estimates the following costs to comply with this proposed AD:

| Action | Labor cost | Parts cost | Cost per
product | Cost on U.S.
operators |
| --- | --- | --- | --- | --- |
| Update software | 3 work-hours × $85 per hour = $255 | $0 | $255 | $67,575 |
| Revise POH | 1 work-hour × $85 per hour = $85 | 0 | 85 | 22,525 |
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. 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

1. The authority citation for part 39 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701.

§ 39.13 [Amended] 2. The FAA amends § 39.13 by adding the following new airworthiness directive:

Pilatus Aircraft Ltd.: Docket No. FAA-2026-2715; Project Identifier MCAI-2025-01779-A.

(a) Comments Due Date

The FAA must receive comments on this airworthiness directive (AD) by May 4, 2026.

(b) Affected ADs

None.

(c) Applicability

This AD applies to Pilatus Aircraft Ltd Model PC-12/47E airplanes, manufacturer serial numbers 1720, and 2001 through 2476, certificated in any category.

(d) Subject

Joint Aircraft System Component (JASC) Code 4500, Central Maint., Computer.

(e) Unsafe Condition

This AD was prompted by a report of the stall warning protection system (SWPS) engaging when not appropriate. The FAA is issuing this AD to ensure the update of the certified operational software and prevent the inappropriate activation of the SWPS. The unsafe condition, if not addressed, could result in reduced safety margins of the airplane, increased pilot workload, and reduced control of the airplane.

(f) Compliance

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

(g) Required Actions

(1) Except as specified in paragraphs (h) and (i) of this AD: Comply with all required actions and compliance times specified in, and in accordance with, European Union Aviation Safety Agency (EASA) AD 2025-0271, dated December 2, 2025 (EASA AD 2025-0271).

(2) The owner/operator (pilot) holding at least a private pilot certificate may revise the existing pilot's operating handbook (POH) for the airplane and must enter compliance with this requirement into the aircraft records 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 2025-0271

(1) Where EASA AD 2025-0271 refers to its effective date, this AD requires using the effective date of this AD.

(2) Where paragraph (4) of EASA AD 2025-0271 specifies to “implement the instructions of the POH-TR, as required by paragraph (4.1) or (4.2) of this AD, as applicable”, this AD requires replacing that text with “revise the Emergency Procedures Section and Airplane and Systems Description of the existing POH for the airplane by inserting a copy of the POH-TR as defined in EASA AD 2025-0271.”

(3) This AD does not adopt the “Remarks” section of EASA AD 2025-0271.

(i) No Reporting Requirement

Although the service material referenced in EASA AD 2025-0271 specifies to submit certain information to the manufacturer, this AD does not include those requirements.

(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: AMOC@faa.gov.

(2) Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the responsible Flight Standards Office/certificate holding district office. ( printed page 13243)

(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: doug.rudolph@faa.gov.

(l) Material Incorporated by Reference

(1) The Director of the Federal Register approved the incorporation by reference (IBR) of the material listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.

(2) You must use this material as applicable to do the actions required by this AD, unless the AD specifies otherwise.

(i) European Union Aviation Safety Agency (EASA) AD 2025-0271, dated December 2, 2025.

(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: ADs@easa.europa.eu; 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, 901 Locust, Kansas City, MO 64106. 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 www.archives.gov/​federal-register/​cfr/​ibr-locations or email fr.inspection@nara.gov.

Issued on March 12, 2026.

Steven W. Thompson,

Acting Deputy Director, Compliance & Airworthiness Division, Aircraft Certification Service.

[FR Doc. 2026-05364 Filed 3-18-26; 8:45 am]

BILLING CODE 4910-13-P

Published Document: 2026-05364 (91 FR 13240)