Airworthiness Directives; Pilatus Aircraft Ltd. Airplanes

[Federal Register Volume 91, Number 145 (Thursday, July 30, 2026)]
[Rules and Regulations]
[Pages 47931-47933]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2026-15467]



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Federal Register / Vol. 91, No. 145 / Thursday, July 30, 2026 / Rules 
and Regulations

[[Page 47931]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2026-0015; Project Identifier MCAI-2025-01528-A; 
Amendment 39-23419; AD 2026-15-07]
RIN 2120-AA64


Airworthiness Directives; Pilatus Aircraft Ltd. Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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

SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
certain Pilatus Aircraft Ltd. (Pilatus) Model PC-12/47E airplanes. 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. This AD requires incorporating a temporary 
revision (TR) 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 issuing this AD to address 
the unsafe condition on these products.

DATES: This AD is effective September 3, 2026.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of September 3, 
2026.

ADDRESSES: 
    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 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.

Material Incorporated by Reference

    <bullet> For European Union Aviation Safety Agency (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 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. It is also available at regulations.govunder 
Docket No. FAA-2026-0015.

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:

Background

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 by adding an AD that would apply to certain Pilatus Model 
PC-12/47E airplanes. The NPRM was published in the Federal Register on 
January 21, 2026 (91 FR 2510). The NPRM was prompted by EASA AD 2025-
0201, dated September 18, 2025 (EASA AD 2025-0201) (also referred to as 
the MCAI), issued by EASA, which is the Technical Agent for the Member 
States of the European Union. 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. This condition, if not 
addressed, could result in reduced turbine blade structural integrity 
with possible engine failure and loss of thrust.
    In the NPRM, the FAA proposed to require incorporating a TR into 
the existing POH for the affected airplanes to provide operators with 
instructions for an enhanced engine start procedure. The FAA is issuing 
this AD to address the unsafe condition on these products.
    You may examine the MCAI in the AD docket at regulations.gov under 
Docket No. FAA-2026-0015.

Discussion of Final Airworthiness Directive

Comments

    The FAA received comments from the Air Line Pilots Association, 
International (ALPA) and an individual commenter who supported the NPRM 
without change.
    The FAA received additional comments from an individual commenter. 
The following presents the comments received on the NPRM and the FAA's 
response to each comment.

Request To Revise Location of TR

    An individual commenter stated that paragraph (h) of the proposed 
AD specified revising the Normal Procedures section of the existing POH 
by inserting a copy of the TR. The commenter noted that Pilatus PC-12/
47E POH TR No. 31, dated July 16, 2025 (TR No. 31), instructs operators 
to insert the TR at the front of the POH. The commenter expressed 
concern that, with the TR inserted at the front of the POH, a pilot 
using the checklist in Section 4, Normal Procedures, might not see the 
revised note or the revised text in step 11. The commenter suggested 
that inserting TR No. 31 in Section 4-5-01, Engine Start (With or 
Without External Power), would ensure that pilots using the checklist 
are aware of the revision and are not required to rely on memory of 
changes located elsewhere in the manual.
    The FAA notes that paragraph (h)(2) of the proposed AD stated that 
TR No. 31 be inserted into the Normal Procedures section of the POH 
instead of at the front of the POH. Further, as explained in the 
Differences Between this AD and the MCAI section of this final rule, 
FAA regulations require operators to furnish pilots with any changes to 
the POH (for example, 14 CFR 135.21). Therefore, no changes to the 
final rule are necessary in response to this comment.

[[Page 47932]]

Request To Revise Level of Emphasis in TR

    An individual commenter stated that the revised text in TR No. 31 
is presented with the same level of emphasis as the original POH 
content, using a ``Note.'' The commenter referenced the definitions 
provided in the POH for ``Warning,'' ``Caution,'' and ``Note,'' and 
indicated that, given the FAA's determination that an AD is necessary, 
the revised text warrants a higher level of emphasis. The commenter 
suggested that the ``Note'' should be elevated to either a ``Caution,'' 
to indicate that damage to the airplane could result, or a ``Warning,'' 
to indicate that personal injury or loss of life is possible if the 
procedure is not strictly followed.
    The FAA disagrees. The State of Design and the type certificate 
holder have determined through their safety assessments that the use of 
a ``Note'' provides an appropriate level of emphasis for the revised 
text. The FAA has reviewed this determination and finds it acceptable.
    The FAA notes that the critical aspect of TR No. 31 is the 
inclusion of additional procedural steps within the checklist, which 
must be followed in the same manner as all other procedures in the POH. 
The FAA further notes that the manufacturer's conventions for the use 
of ``Warnings'' and ``Cautions'' are applied consistently and are 
generally not used for standard airmanship actions addressed through 
normal procedures.
    The FAA has determined that the actions required by this AD 
adequately address the identified unsafe condition by ensuring that the 
revised procedures are incorporated and followed, thereby preventing 
operation of the airplane with a compromised engine condition.
    The FAA has made no changes to the final rule in response to this 
comment.

Request To Update Electronic and Paper Checklists

    An individual commenter stated that the electronic and paper 
checklists have not been revised to include the same text as TR No. 31. 
The commenter noted that there is no indication within those checklists 
to alert the pilot that a change has been made and acknowledged that 
the airplane flight manual POH is the FAA-approved document. The FAA 
infers that the commenter is requesting that the electronic and paper 
checklists be updated or otherwise revised to reflect the changes in TR 
No. 31 to ensure pilots are aware of the revised procedures.
    The FAA disagrees. Paragraph (h)(2) of this AD requires revising 
the Normal Procedures section of the existing POH, which requires any 
checklists to be updated to match the revised POH. Pilatus is updating 
their provided checklist that is inside the Quick Reference Handbook. 
If operators develop their own checklists, they must update them to 
match this POH change. As was explained in the Differences Between this 
AD and the MCAI section of the NPRM and this final rule, 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). Therefore, the FAA has made no changes to this AD in 
response to this comment.

Conclusion

    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. Except for 
minor editorial changes, this AD is adopted as proposed in the NPRM. 
None of the changes will increase the economic burden on any operator.

Material Incorporated by Reference Under 1 CFR Part 51

    The FAA reviewed EASA AD 2025-0201, which specifies procedures for 
incorporating TR No. 31 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.

Differences Between This 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 AD does 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.

Interim Action

    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.

Costs of Compliance

    The FAA estimates that this AD affects 265 airplanes of U.S. 
registry. The FAA estimates the following costs to comply with this:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost           Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
Revise POH............................  1 work-hour x $85 per                 $0             $85         $22,525
                                         hour = $85.
----------------------------------------------------------------------------------------------------------------

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

[[Page 47933]]

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,
    (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.

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:

2026-15-07 Pilatus Aircraft Ltd.: Amendment 39-23419; Docket No. 
FAA-2026-0015; Project Identifier MCAI-2025-01528-A.

(a) Effective Date

    This airworthiness directive (AD) is effective September 3, 
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 
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 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 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, 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 www.archives.gov/federal-register/cfr/ibr-locations or email [email protected].

    Issued on July 16, 2026.
Steven W. Thompson,
Acting Deputy Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2026-15467 Filed 7-29-26; 8:45 am]
BILLING CODE 4910-13-P

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