Proposed Rule2026-06605
Airworthiness Directives; Pilatus Aircraft Ltd. Airplanes
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
April 6, 2026
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
The FAA proposes to supersede Airworthiness Directive (AD) 2021-11-08, which applies to all Pilatus Aircraft Ltd. (Pilatus) Model PC-6, PC-6-H1, PC-6-H2, PC-6/350, PC-6/350-H1, PC-6/350-H2, PC-6/A, PC- 6/A-H1, PC-6/A-H2, PC-6/B-H2, PC-6/B1-H2, PC-6/B2-H2, PC-6/B2-H4, PC-6/ C-H2, and PC-6/C1-H2 airplanes. AD 2021-11-08 requires revising the airworthiness limitation section (ALS) of the existing aircraft maintenance manual (AMM) or instructions for continued airworthiness (ICA) to incorporate new airworthiness limitations and adding an additional eddy current inspection of the fuselage wing fittings and wing-to-fuselage fittings if the last inspection was performed using an earlier version of the material. Since the FAA issued AD 2021-11-08, the FAA has determined that new or more restrictive airworthiness limitations are necessary. This proposed AD would require revising the ALS of the existing AMM or ICA for these airplanes. 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 65 (Monday, April 6, 2026)</title>
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[Federal Register Volume 91, Number 65 (Monday, April 6, 2026)]
[Proposed Rules]
[Pages 17161-17164]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2026-06605]
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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.
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Federal Register / Vol. 91, No. 65 / Monday, April 6, 2026 / Proposed
Rules
[[Page 17161]]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2026-3474; Project Identifier MCAI-2025-01807-A]
RIN 2120-AA64
Airworthiness Directives; Pilatus Aircraft Ltd. Airplanes
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: The FAA proposes to supersede Airworthiness Directive (AD)
2021-11-08, which applies to all Pilatus Aircraft Ltd. (Pilatus) Model
PC-6, PC-6-H1, PC-6-H2, PC-6/350, PC-6/350-H1, PC-6/350-H2, PC-6/A, PC-
6/A-H1, PC-6/A-H2, PC-6/B-H2, PC-6/B1-H2, PC-6/B2-H2, PC-6/B2-H4, PC-6/
C-H2, and PC-6/C1-H2 airplanes. AD 2021-11-08 requires revising the
airworthiness limitation section (ALS) of the existing aircraft
maintenance manual (AMM) or instructions for continued airworthiness
(ICA) to incorporate new airworthiness limitations and adding an
additional eddy current inspection of the fuselage wing fittings and
wing-to-fuselage fittings if the last inspection was performed using an
earlier version of the material. Since the FAA issued AD 2021-11-08,
the FAA has determined that new or more restrictive airworthiness
limitations are necessary. This proposed AD would require revising the
ALS of the existing AMM or ICA for these airplanes. 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 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-2026-3474; 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 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#d59491a695b0b4a6b4fbb0a0a7baa5b4fbb0a0"><span class="__cf_email__" data-cfemail="79383d0a391c180a18571c0c0b160918571c0c">[email 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, 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: <a href="/cdn-cgi/l/email-protection#d9bdb6acbef7abacbdb6b5a9b199bfb8b8f7beb6af"><span class="__cf_email__" data-cfemail="44202b31236a3631202b28342c042225256a232b32">[email 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-2026-3474; Project Identifier
MCAI-2025-01807-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 2021-11-08, Amendment 39-21570 (86 FR 30155, June
7, 2021), (AD 2021-11-08), for all Pilatus Model PC-6, PC-6-H1, PC-6-
H2, PC-6/350, PC-6/350-H1, PC-6/350-H2, PC-6/A, PC-6/A-H1, PC-6/A-H2,
PC-6/B-H2, PC-6/B1-H2, PC-6/B2-H2, PC-6/B2-H4, PC-6/C-H2, and PC-6/C1-
H2 airplanes. AD 2021-11-08 was prompted by an MCAI originated by EASA,
which is the Technical Agent for the Member States of the European
Union. EASA issued EASA AD 2007-0241R4, dated August 31, 2010, (EASA AD
2007-0241R4) to correct an unsafe condition identified as corrosion,
wear, and cracks in the upper wing strut fittings on some PC-6
airplanes. EASA also issued EASA AD 2020-0278, dated
[[Page 17162]]
December 14, 2020, (EASA AD 2020-0278) to correct an unsafe condition
identified as a failure to revise the ALS of the existing AMM by
introducing new or more restrictive tasks and limitations, including
corrected material which includes installing certain bushes using
grease instead of a bonding agent and an additional one-time eddy
current inspection of the fuselage wing fittings and wing-to-fuselage
fittings if the last inspection was performed using an earlier version
of the material. EASA AD 2020-0278 states that these instructions have
been identified as mandatory for continued airworthiness, and failure
to accomplish them could result in an unsafe condition.
AD 2021-11-08 requires revising the ALS of the existing AMM or ICA
to incorporate new airworthiness limitations and adding an additional
eddy current inspection of the fuselage wing fittings and wing-to-
fuselage fittings if the last inspection was performed using an earlier
version of the material. The FAA issued AD 2021-11-08 to address
reduced airplane controllability due to possible loss of structural
integrity of certain parts.
Actions Since AD 2021-11-08 Was Issued
Since the FAA issued AD 2021-11-08, EASA superseded EASA AD 2007-
0241R4 and EASA AD 2020-0278 and issued EASA AD 2025-0281, dated
December 11, 2025 (EASA AD 2025-0281) (also referred to as the MCAI),
for all Pilatus Model PC-6 airplanes. The MCAI states that new or more
restrictive tasks and limitations have been developed. These include
adding life limits for the control column pitch trim relay. The MCAI
also states that failure to accomplish these instructions could result
in an unsafe condition. The FAA is issuing this AD to address failure
of certain parts, which could result in loss of control of the
airplane.
Additionally, the actions required to address the unsafe condition
in AD 2021-11-08 are included in ``the applicable ALS,'' as defined in
EASA AD 2025-0281.
You may examine the MCAI in the AD docket at <a href="http://regulations.gov">regulations.gov</a> under
Docket No. FAA-2026-3474.
Material Incorporated by Reference Under 1 CFR Part 51
The FAA reviewed EASA AD 2025-0281, which specifies procedures for
revising the aircraft maintenance program (AMP) by incorporating
airworthiness limitations, tasks, and associated thresholds and
intervals, including life limits and maintenance tasks. EASA AD 2025-
0281 also specifies performing corrective actions if any discrepancy is
found during accomplishment of any task in paragraph (1) of EASA AD
2025-0281 and revising the AMP by incorporating the limitations, tasks,
and associated thresholds and intervals described in ``the applicable
ALS'' as defined in EASA AD 2025-0281.
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 revising the ALS of the existing AMM
or ICA for the airplane and the existing approved maintenance or
inspection program, as applicable, by incorporating new or more
restrictive actions and associated thresholds and intervals, including
any life limits, specified in EASA AD 2025-0281, described previously,
as incorporated by reference, except for any differences identified as
exceptions in the regulatory text of this proposed AD. See
``Differences Between this NPRM and the MCAI'' for a discussion of the
general differences included in this proposed AD.
The owner/operator (pilot) holding at least a private pilot
certificate may revise the ALS of the existing AMM or ICA for the
airplane, and performance of this incorporation must be entered into
the aircraft records showing compliance with this AD in accordance with
14 CFR 43.9(a) and 14 CFR 91.417(a)(2)(v). The record must be
maintained as required by 14 CFR 91.417, 121.380, or 135.439.
Differences Between This Proposed AD and the MCAI
Where EASA AD 2025-0281 specifies revising the approved AMP within
12 months after the effective date of EASA AD 2025-0281, this proposed
AD would require revising the ALS of the existing approved maintenance
or inspection program, as applicable, within 30 days after the
effective date of this proposed AD.
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 2025-0281 by reference in the FAA final rule. This proposed AD
would, therefore, require compliance with EASA AD 2025-0281 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 2025-0281 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 2025-0281. Material required by
EASA AD 2025-0281 for compliance will be available at <a href="http://regulations.gov">regulations.gov</a>
under Docket No. FAA-2026-3474 after the FAA final rule is published.
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would
affect 30 airplanes of U.S. registry.
The FAA estimates the following costs to comply with this proposed
AD:
[[Page 17163]]
Estimated Costs
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Cost per Cost on U.S.
Action Labor cost Parts cost product operators
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Revise the ALS........................... 1 work-hour x $85 per hour $0 $85 $2,550
= $85.
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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 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 2021-11-08, Amendment 39-21570 (86
FR 30155, June 7, 2021); and
0
b. Adding the following new airworthiness directive:
Pilatus Aircraft Ltd.: Docket No. FAA-2026-3474; Project Identifier
MCAI-2025-01807-A.
(a) Comments Due Date
The FAA must receive comments on this airworthiness directive
(AD) by May 21, 2026.
(b) Affected ADs
This AD replaces AD 2021-11-08, Amendment 39-21570 (86 FR 30155,
June 7, 2021); (AD 2021-11-08).
(c) Applicability
This AD applies to all Pilatus Aircraft Ltd., Model PC-6, PC-6-
H1, PC-6-H2, PC-6/350, PC-6/350-H1, PC-6/350-H2, PC-6/A, PC-6/A-H1,
PC-6/A-H2, PC-6/B-H2, PC-6/B1-H2, PC-6/B2-H2, PC-6/B2-H4, PC-6/C-H2,
and PC-6/C1-H2 airplanes, certificated in any category.
Note 1 to paragraph (c): These airplanes may also be identified
as Fairchild Republic Company airplanes, Fairchild Industries
airplanes, Fairchild Heli Porter airplanes, or Fairchild-Hiller
Corporation airplanes.
(d) Subject
Joint Aircraft System Component (JASC) Code 2740, Stabilizer
Control System.
(e) Unsafe Condition
This AD was prompted by a revision to the airworthiness
limitations section (ALS) of the existing aircraft maintenance
manual (AMM) introducing new and more restrictive instructions and
maintenance tasks. These include adding life limits for the control
column pitch trim relay. The FAA is issuing this AD to ensure
revision of the ALS of the existing AMM or instructions for
continued airworthiness (ICA) for the airplane. The unsafe
condition, if not addressed, could result in failure of certain
parts, which could result in loss of 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 2025-0281, dated December 11, 2025 (EASA AD 2025-0281).
(2) The actions required by 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 2025-0281
(1) Where EASA AD 2025-0281 refers to its effective date, this
AD requires using the effective date of this AD.
(2) This AD does not adopt paragraphs (1), (2), (4), and (5) of
EASA AD 2025-0281.
(3) Where paragraph (3) of EASA AD 2025-0281 specifies ``Within
12 months after the effective date of this AD, revise the approved
AMP,'' this AD requires replacing that text with ``Within 30 days
after the effective date of this AD, revise the ALS of the existing
AMM or ICA and the existing approved maintenance or inspection
program, as applicable.''
(4) The initial compliance time for doing the tasks specified in
paragraph (3) of EASA AD 2025-0281 is on or before the applicable
limitations and associated thresholds as incorporated by the
requirements of paragraph (3) of EASA AD 2025-0281 or within 30 days
after the effective date of this AD, whichever occurs later.
(5) This AD does not adopt the ``Remarks'' section of EASA AD
2025-0281.
(i) Provisions for Alternative Actions and Intervals
After the action required by paragraph (g)(1) of this AD has
been done, no alternative actions and associated thresholds and
intervals, including any life limits, are allowed unless they are
approved as specified in the provisions of the ``Ref. Publications''
section of EASA AD 2025-0281.
(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
[[Page 17164]]
identified in paragraph (k) of this AD and email to: <a href="/cdn-cgi/l/email-protection#6524282a26250304044b020a13"><span class="__cf_email__" data-cfemail="99d8d4d6dad9fff8f8b7fef6ef">[email protected]</span></a>.
(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.
(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#fa9e958f9dd4888f9e95968a92ba9c9b9bd49d958c"><span class="__cf_email__" data-cfemail="9cf8f3e9fbb2eee9f8f3f0ecf4dcfafdfdb2fbf3ea">[email protected]</span></a>.
(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 2025-0281,
dated December 11, 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: <a href="/cdn-cgi/l/email-protection#47060334072226342669223235283726692232"><span class="__cf_email__" data-cfemail="e0a1a493a085819381ce8595928f9081ce8595">[email 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, 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 <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#2046520e494e5350454354494f4e604e4152410e474f56"><span class="__cf_email__" data-cfemail="0d6b7f2364637e7d686e796462634d636c7f6c236a627b">[email protected]</span></a>.
Issued on March 31, 2026.
Christopher R. Parker,
Acting Deputy Director, Compliance & Airworthiness Division, Aircraft
Certification Service.
[FR Doc. 2026-06605 Filed 4-3-26; 8:45 am]
BILLING CODE 4910-13-P
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