Airworthiness Directives; Pilatus Aircraft Ltd. Airplanes

<RULE> DEPARTMENT OF TRANSPORTATION <SUBAGY>Federal Aviation Administration</SUBAGY> <CFR>14 CFR Part 39</CFR> <DEPDOC>[Docket No. FAA-2025-0917; Project Identifier MCAI-2024-00740-A; Amendment 39-23155; AD 2025-20-02]</DEPDOC> <RIN>RIN 2120-AA64</RIN> <SUBJECT>Airworthiness Directives; Pilatus Aircraft Ltd. Airplanes</SUBJECT> <HD SOURCE="HED">AGENCY:</HD> Federal Aviation Administration (FAA), DOT. <HD SOURCE="HED">ACTION:</HD> Final rule. <SUM> <HD SOURCE="HED">SUMMARY:</HD> The FAA is adopting a new airworthiness directive (AD) for all Pilatus Aircraft Ltd. (Pilatus) Model PC-24 airplanes. This AD was prompted by a report of an inaccurate flight director calculation on approach. This AD requires incorporating a temporary revision into the existing airplane flight manual (AFM) for the affected airplanes, which revises the Abnormal Procedures Section. The FAA is issuing this AD to address the unsafe condition on these products. </SUM> <EFFDATE> <HD SOURCE="HED">DATES:</HD> This AD is effective December 30, 2025. The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of December 30, 2025. </EFFDATE> <HD SOURCE="HED">ADDRESSES:</HD> <E T="03">AD Docket:</E> You may examine the AD docket at <E T="03">regulations.gov</E> under Docket No. FAA-2025-0917; 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, the mandatory continuing airworthiness information (MCAI), any comments received, and other information. The address for Docket Operations is U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590. <E T="03">Material Incorporated by Reference:</E> • For European Union Aviation Agency (EASA) material identified in this AD, contact EASA, Konrad-Adenauer-Ufer 3, 50668 Cologne, Germany; phone: +49 221 8999 000; email: <E T="03">ADs@easa.europa.eu;</E> website: <E T="03">easa.europa.eu.</E> You may find this material on the EASA website at <E T="03">ad.easa.europa.eu.</E> • 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. <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> Doug Rudolph, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (816) 329-4059; email: <E T="03">doug.rudolph@faa.gov.</E> </FURINF> <SUPLINF> <HD SOURCE="HED">SUPPLEMENTARY INFORMATION:</HD> <HD SOURCE="HD1">Background</HD> The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to all Pilatus Model PC-24 airplanes. The NPRM was published in the <E T="04">Federal Register</E> on June 18, 2025 (90 FR 25909). The NPRM was prompted by AD 2024-0240, dated December 10, 2024, issued by EASA, which is the Technical Agent for the Member States of the European Union (also referred to as the MCAI). The MCAI states there was a report of an inaccurate flight director calculation on approach with APEX Build 5.3 and below software installed. Further investigation revealed that heading splits can cause errors in the flight director calculation, resulting in lateral offsets to the desired approach course. The MCAI also states that the AD is considered an interim action and further AD action may follow. In the NPRM, the FAA proposed to require incorporating a temporary revision into the existing airplane flight manual (AFM) for the affected airplanes, which revises the Abnormal Procedures Section. The FAA is issuing this AD to address the unsafe condition on these products. You may examine the MCAI in the AD docket at <E T="03">regulations.gov</E> under Docket No. FAA-2025-0917. <HD SOURCE="HD1">Discussion of Final Airworthiness Directive</HD> <HD SOURCE="HD1">Comments</HD> The FAA received no comments on the NPRM or on the determination of the costs. <HD SOURCE="HD1">Conclusion</HD> These products have been approved by the civil aviation authority 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 reviewed the relevant data, considered any comments received, and determined that air safety requires adopting this AD as proposed. Accordingly, the FAA is issuing this AD to address the unsafe condition on these products. This AD is adopted as proposed in the NPRM. <HD SOURCE="HD1">Material Incorporated by Reference Under 1 CFR Part 51</HD> The FAA reviewed EASA AD 2024-0240, which specifies procedures for incorporating Pilatus PC-24 AFM Temporary Revision 02371-075 (also referred to as AFM-TR) into the AFM, which revises the Abnormal Procedures Section. EASA AD 2024-0240 also specifies informing all flight crews of the change, and, thereafter, operating the airplane accordingly, and allows for the incorporation of a later AFM revision that includes the same AFM 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 <E T="02">ADDRESSES</E> section. <HD SOURCE="HD1">Differences Between This AD and the MCAI</HD> EASA AD 2024-0240 includes requirements to “inform all flight crews and, thereafter, operate the [airplane] accordingly”, and this AD does not specifically require those actions because those actions are already required by existing FAA regulations (see 14 CFR 91.9, 91.505, and 135.21). <HD SOURCE="HD1">Interim Action</HD> The FAA considers this AD 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. <HD SOURCE="HD1">Costs of Compliance</HD> The FAA estimates that this AD affects 150 airplanes of U.S. registry. The FAA estimates the following costs to comply with this AD: <GPOTABLE COLS="5" OPTS="L2,i1" CDEF="s50,r50,12C,12C,12C"> <TTITLE>Estimated Costs</TTITLE> <CHED H="1">Action</CHED> <CHED H="1">Labor cost</CHED> <CHED H="1">Parts cost</CHED> Cost on U.S. operators </CHED> <ROW> <ENT I="01">Revise AFM</ENT> <ENT>1 work-hour × $85 per hour = $85</ENT> <ENT>$0</ENT> <ENT>$85</ENT> <ENT>$12,750</ENT> </ROW> </GPOTABLE> <HD SOURCE="HD1">Authority for This Rulemaking</HD> 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. <HD SOURCE="HD1">Regulatory Findings</HD> 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, (2) Will not affect intrastate aviation in Alaska, and (3) Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. <LSTSUB> <HD SOURCE="HED">List of Subjects in 14 CFR Part 39</HD> Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety. </LSTSUB> <HD SOURCE="HD1">The Amendment</HD> Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows: <HD SOURCE="HED">PART 39—AIRWORTHINESS DIRECTIVES</HD> <REGTEXT TITLE="14" PART="39"> 1. The authority citation for part 39 continues to read as follows: <HD SOURCE="HED">Authority:</HD> 49 U.S.C. 106(g), 40113, 44701. </REGTEXT> <SECTION> <SECTNO>§ 39.13 </SECTNO> <SUBJECT>[Amended]</SUBJECT> </SECTION> <REGTEXT TITLE="14" PART="39"> 2. The FAA amends § 39.13 by adding the following new airworthiness directive: <EXTRACT> <FP SOURCE="FP-2"> <E T="04">2025-20-02 Pilatus Aircraft Ltd.:</E> Amendment 39-23155; Docket No. FAA-2025-0917; Project Identifier MCAI-2024-00740-A. </FP> <HD SOURCE="HD1">(a) Effective Date</HD> This airworthiness directive (AD) is effective December 30, 2025. <HD SOURCE="HD1">(b) Affected ADs</HD> None. <HD SOURCE="HD1">(c) Applicability</HD> This AD applies to Pilatus Aircraft Ltd Model PC-24 airplanes, certificated in any category. <HD SOURCE="HD1">(d) Subject</HD> Joint Aircraft System Component (JASC) Code 3400, Navigation System. <HD SOURCE="HD1">(e) Unsafe Condition</HD> This AD was prompted by a report 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. 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