# [Amended]
**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 proposed AD was prompted by a report that, during an engine start on the ground, the airplane battery voltage dropped to a value that resulted in an avionic system shutdown. This proposed AD would require incorporating a temporary revision into the existing pilot's operating handbook (POH) for the affected airplanes to provide operators with instructions for an enhanced engine start procedure. The FAA is proposing this AD to address the unsafe condition on these products.
**DATES:**
The FAA must receive comments on this NPRM by March 9, 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-2026-0015; 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:*
• 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: *[email protected];* 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: *[email protected].*
**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-2026-0015; Project Identifier MCAI-2025-01528-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 2025-0201, dated September 18, 2025 (EASA AD 2025-0201) (also referred to as the MCAI), to correct an unsafe condition on certain Pilatus Model PC-12/47E airplanes. The MCAI states that there was an occurrence reported where during an engine start on the ground, the airplane battery voltage dropped to a value that resulted in an avionic system shutdown. As a result, the engine parameters, including the interstage turbine temperature (ITT) indications were undetectable, and the ITT exceedance protection during the engine ground start procedure was deactivated. Under these conditions, an ITT exceedance could occur with the aircrew having no means to detect it. The MCAI also states that the AD is considered an interim action and further AD action may follow. This condition, if not addressed, could result in reduced turbine blade structural integrity with possible engine failure and loss of thrust.
You may examine the MCAI in the AD docket at *regulations.gov* under Docket No. FAA-2026-0015.
**Material Incorporated by Reference Under 1 CFR Part 51**
The FAA reviewed EASA AD 2025-0201, which specifies procedures for incorporating Pilatus PC-12/47E POH Temporary Revision (TR) No. 31 (also referred to as POH-TR) into the POH and allows for the incorporation of a later POH revision that includes the same POH amendment content. 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. See “Differences Between this Proposed AD and the MCAI” for a discussion of the general differences included in this AD. The owner/operator (pilot) holding at least a private pilot certificate may revise the existing POH for your 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.
**Differences Between This Proposed AD and the MCAI**
The MCAI requires operators to “inform all flight crew” of the revisions to the POH, and thereafter to “operate the airplane accordingly.” However, this proposed AD would not specifically require those actions as those actions are already required by FAA regulations. FAA regulations require operators to furnish pilots with any changes to the POH (for example, 14 CFR 135.21), and require pilots to comply with the POH (14 CFR 91.9). As with any other flight crew training requirement, training on the updated POH content is tracked by the operators and recorded in each pilot's training record, which is available for the FAA to review. FAA regulations also require pilots to follow the procedures in the existing POH including all updates. Therefore, including a requirement in this AD to inform the flight crew and operate the airplane according to the revised POH would be redundant and unnecessary.
**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 since coordinated with other manufacturers and CAAs to use this process. As a result, the FAA proposes to incorporate by reference EASA AD 2025-0201 in the FAA final rule. This proposed AD would, therefore, require compliance with EASA AD 2025-0201 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 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 2025-0201. Service information required by the EASA AD for compliance will be available at regulations.gov under Docket No. FAA-2026-0015 after the FAA final rule is published.
**Interim Action**
The FAA considers that this proposed AD would be an interim action. This unsafe condition is still under investigation by the manufacturer and, depending on the results of that investigation, the FAA may consider further rulemaking action.
**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 | Cost on U.S. |
| --- | --- | --- | --- | --- |
| Revise POH | 1 work-hour × $85 per hour = $85 | $0 | $85 | $22,525 |
**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
2. The FAA amends § 39.13 by adding the following new airworthiness directive:
*Pilatus Aircraft Ltd.:* Docket No. FAA-2026-0015; Project Identifier MCAI-2025-01528-A.
**(a) Comments Due Date**
The FAA must receive comments on this airworthiness directive (AD) by March 9, 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 2999, certificated in any category.
**(d) Subject**
Joint Aircraft System Component (JASC) Code 7720, Engine Temp. Indicating System.
**(e) Unsafe Condition**
This AD was prompted by a report that during an engine start on the ground, the airplane battery voltage dropped to a value that resulted in an avionic system shutdown. The FAA is issuing this AD to prevent takeoff when an undetected interstage turbine temperature (ITT) exceedance occurs during engine start. The unsafe condition, if not addressed, could result in reduced turbine blade structural integrity with possible engine failure and loss of thrust.
**(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, European Union Aviation Safety Agency AD 2025-0201, dated September 18, 2025 (EASA AD 2025-0201).
(2) The actions required by paragraph (g)(1) of this AD may be performed by the owner/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 2025-0201**
(1) Where EASA AD 2025-0201 refers to its effective date, this AD requires using the effective date of this AD.
(2) Where paragraph (1) of EASA AD 2025-0201 specifies to “implement the POH-TR, as defined in this AD”, this AD requires replacing that text with “revise the Normal Procedures Section of the existing pilot's operating handbook (POH) for your airplane by inserting a copy of the POH-TR as defined in EASA AD 2025-0201.”
(3) Where paragraph (1) of EASA AD 2025-0201 specifies to inform all flight crews and, thereafter, operate the [airplane] accordingly, this AD does not require those actions (see 14 CFR 91.9, 91.103, and 135.21).
(4) This AD does not adopt the “Remarks” section of EASA AD 2025-0201.
**(i) 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 (j) 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/certificate holding district office.
**(j) 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: *[email protected].*
**(k) 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 2025-0201, dated September 18, 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: *[email protected];* 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 *[email protected].*
Issued on January 13, 2026.
Steven W. Thompson,
Acting Deputy Director, Compliance & Airworthiness Division, Aircraft Certification Service.