Proposed Rule2025-02932
Airworthiness Directives; Pilatus Aircraft Ltd. Airplanes
Primary source
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Published
February 24, 2025
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
The FAA proposes to supersede Airworthiness Directive (AD) 2023-26-05, which applies to certain Pilatus Aircraft Ltd. (Pilatus) Model PC-24 airplanes. AD 2023-26-05 requires periodic replacement of affected titanium threaded bolts, a one-time inspection of the rudder mass balance arm and other elements of the rudder trim tab installation for correct attachment, damage (gouges), cracks, deformation, surface finish, and corrosion on any surrounding parts and, depending on findings, the accomplishment of applicable corrective actions. Since the FAA issued AD 2023-26-05, it was determined that some batches of titanium bolts had variations in the microstructure that could affect the fatigue characteristics. This proposed AD would require replacing affected short rudder-trim control rod assemblies with serviceable rudder-trim control rod assemblies having threaded steel bolts and would prohibit the installation of affected parts, as specified in a European Union Aviation Safety Agency (EASA) AD, which is proposed for incorporation by reference. The FAA is proposing this AD to address the unsafe condition on these products.
Full Text
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<title>Federal Register, Volume 90 Issue 35 (Monday, February 24, 2025)</title>
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[Federal Register Volume 90, Number 35 (Monday, February 24, 2025)]
[Proposed Rules]
[Pages 10467-10470]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2025-02932]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2025-0208; Project Identifier MCAI-2024-00555-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)
2023-26-05, which applies to certain Pilatus Aircraft Ltd. (Pilatus)
Model PC-24 airplanes. AD 2023-26-05 requires periodic replacement of
affected titanium threaded bolts, a one-time inspection of the rudder
mass balance arm and other elements of the rudder trim tab installation
for correct attachment, damage (gouges), cracks, deformation, surface
finish, and corrosion on any surrounding parts and, depending on
findings, the accomplishment of applicable corrective actions. Since
the FAA issued AD 2023-26-05, it was determined that some batches of
titanium bolts had variations in the microstructure that could affect
the fatigue characteristics. This proposed AD would require replacing
affected short rudder-trim control rod assemblies with serviceable
rudder-trim control rod assemblies having threaded steel bolts and
would prohibit the installation of affected parts, as
[[Page 10468]]
specified in a European Union Aviation Safety Agency (EASA) AD, which
is proposed for incorporation by reference. The FAA is proposing this
AD to address the unsafe condition on these products.
DATES: The FAA must receive comments on this NPRM by April 10, 2025.
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-2025-0208; 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 EASA material identified in this proposed AD, contact
EASA, Konrad-Adenauer-Ufer 3, 50668 Cologne, Germany; phone: +49 221
8999 000; email: <a href="/cdn-cgi/l/email-protection#6223261122070311034c0717100d12034c0717"><span class="__cf_email__" data-cfemail="bbfaffc8fbdedac8da95decec9d4cbda95dece">[email protected]</span></a>; website: easa.europa.eu. You may
find this material on the EASA website at ad.easa.europa.eu. It is also
available at <a href="http://regulations.gov">regulations.gov</a> under Docket No. FAA-2025-0208.
<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#7a1e150f1d54080f1e15160a123a1c1b1b541d150c"><span class="__cf_email__" data-cfemail="55313a20327b2720313a39253d153334347b323a23">[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 to an address listed
under ADDRESSES. Include ``Docket No. FAA-2025-0208; Project Identifier
MCAI-2024-00555-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 2023-26-05, Amendment 39-22648 (88 FR 90091,
December 29, 2023) (AD 2023-26-05), for certain Pilatus Model PC-24
airplanes. AD 2023-26-05 was prompted by an MCAI originated by EASA,
which is the Technical Agent for the Member States of the European
Union. EASA issued Emergency AD 2023-0219-E, dated December 19, 2023
(EASA Emergency AD 2023-0219-E), to correct an unsafe condition on
certain Pilatus Model PC-24 airplanes. If not corrected, the unsafe
condition could lead to failure of the titanium threaded bolts with
consequent damage to the rudder and rudder trim tab, which could result
in loss of rudder control and reduced or loss of control of the
airplane. EASA Emergency AD 2023-0219-E identified the affected parts
as titanium threaded bolts, part number (P/N) 527.20.24.489, installed
on the rudder trim tab short control rods.
AD 2023-26-05 requires periodic replacement of affected titanium
threaded bolts, a one-time inspection of the rudder mass balance arm
and other elements of the rudder trim tab installation for correct
attachment, damage (gouges), cracks, deformation, surface finish, and
corrosion on any surrounding parts and, depending on findings,
accomplishment of applicable corrective actions. The FAA issued AD
2023-26-05 to address the unsafe condition on these products.
Actions Since AD 2023-26-05 Was Issued
Since the FAA issued AD 2023-26-05, EASA superseded EASA Emergency
AD 2023-0219-E and issued EASA AD 2024-0181R1, dated September 24, 2024
(EASA AD 2024-0181R1) (also referred to as the MCAI) for certain
Pilatus Model PC-24 airplanes. The MCAI states that the titanium
threaded bolts at the forward end of the short rudder trim tab
actuating rods may be subject to unexpectedly high oscillating loads
due to aerodynamic forces acting on the rudder trim tab. This condition
could lead to failure of the bolt and consequent damage to the rudder
and rudder trim tab, possibly resulting in loss of rudder control and
reduced or loss of control of the airplane. The MCAI also states that
variations in the structures of the replacement titanium bolt batches
could affect their fatigue characteristics.
The FAA is proposing this AD to address the unsafe condition on
these products.
You may examine the MCAI in the AD docket at <a href="http://regulations.gov">regulations.gov</a> under
Docket No. FAA-2025-0208.
Material Incorporated by Reference Under 1 CFR Part 51
The FAA reviewed EASA AD 2024-0181R1, which specifies replacing an
affected part, short rudder-trim control rod assembly P/N
527.20.24.464, which has threaded titanium bolts, with a serviceable
part, short rudder-trim control rod assembly P/N 527.20.24.069, which
has threaded steel bolts. EASA AD 2024-0181R1 prohibits the
installation of an affected part on any airplane.
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.
[[Page 10469]]
FAA's Determination
These products have been approved by the 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, it 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 retain none of the requirements of AD 2023-
26-05. This proposed AD would require accomplishing the actions
specified in EASA AD 2024-0181R1 described previously, except for any
differences identified as exceptions in the regulatory text 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 EASA 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 EASA. As a result, the FAA proposes to incorporate
EASA AD 2024-0181R1 by reference in the FAA final rule. This proposed
AD would, therefore, require compliance with EASA AD 2024-0181R1 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 2024-0181R1 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 2021-0181R1. Material required by
EASA AD 2024-0181R1 for compliance will be available at <a href="http://regulations.gov">regulations.gov</a>
under Docket No. FAA-2025-0208 after the FAA final rule is published.
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would
affect 120 airplanes of U.S. registry.
The FAA estimates the following costs to comply with this proposed
AD:
Estimated Costs
----------------------------------------------------------------------------------------------------------------
Cost per Cost on U.S.
Action Labor cost Parts cost product operators
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Replacement of affected rudder-trim 8 work-hours x $85 per $288 $968 $116,160
control rod assemblies. hour = $680.
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The FAA has included all known costs in its cost estimate.
According to the manufacturer, however, some of the costs of this
proposes 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 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(f), 40113, 44701.
Sec. 39.13 [Amended]
0
2. The FAA amends Sec. 39.13 by:
0
a. Removing Airworthiness Directive 2023-26-05, Amendment 39-22648 (88
FR 90091, December 29, 2023); and
0
b. Adding the following new airworthiness directive:
Pilatus Aircraft Ltd.: Docket No. FAA-2025-0208; Project Identifier
MCAI-2024-00555-A.
(a) Comments Due Date
The FAA must receive comments on this airworthiness directive
(AD) by April 10, 2025.
(b) Affected ADs
This AD replaces AD 2023-26-05, Amendment 39-22648 (88 FR 90091,
December 29, 2023) (AD 2023-26-05).
(c) Applicability
This AD applies to Pilatus Aircraft Ltd. Model PC-24 airplanes,
certificated in any category, as identified in European Union
Aviation Safety Agency (EASA) AD 2024-0181R1, dated September 24,
2024 (EASA AD 2024-0181R1).
(d) Subject
Joint Aircraft System Component (JASC) Code 2721, Rudder Tab
Control System.
(e) Unsafe Condition
This AD was prompted by a determination that the titanium
threaded bolts installed at the forward end of the short rudder trim
tab actuating rods could be subject to
[[Page 10470]]
unexpectedly high oscillating loads due to aerodynamic forces acting
on the rudder trim tab. The FAA is issuing this AD to address the
unsafe condition. The unsafe condition, if not addressed, could
result in failure of the titanium threaded bolts with consequent
damage to the rudder and rudder trim tab, which could result in loss
of rudder control and reduced or loss of control of the airplane.
(f) Compliance
Comply with this AD within the compliance times specified,
unless already done.
(g) Required Actions
Except as specified in paragraph (h) of this AD: Comply with all
required actions and compliance times specified in, and in
accordance with, EASA AD 2024-0181R1.
(h) Exceptions to EASA AD 2024-0181R1
(1) Where EASA AD 2024-0181R1 refers to its effective date, this
AD requires using the effective date of this AD.
(2) Where EASA AD 2024-0181R1 requires compliance in terms of
flight hours, this AD requires using hours time-in-service.
(3) Where paragraph (1) of EASA AD 2024-0181R1 specifies ``as
required by EASA AD 2023-0219-E'', this AD requires replacing that
text with ``as required by AD 2023-26-05.''
(4) Where the material identified in EASA AD 2024-0181R1
specifies to ``discard'' certain parts, this AD requires replacing
that text with ``remove from service.''
(5) This AD does not adopt the Remarks section of EASA AD 2024-
0181R1.
(i) Alternative Methods of Compliance (AMOCs)
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, mail
it to the address identified in paragraph (j) of this AD or email
to: <a href="/cdn-cgi/l/email-protection#3a7b7775797a5c5b5b145d554c"><span class="__cf_email__" data-cfemail="16575b59555670777738717960">[email protected]</span></a>. If mailing information, also submit information by
email. Before using any approved AMOC, notify your appropriate
principal inspector, or lacking a principal inspector, the manager
of the local Flight Standards District Office/certificate holding
district office. Only Global AMOC letter 731-24-00656, dated July
24, 2024, approved for AD 2023-26-05, is approved as an AMOC for the
corresponding provisions of this AD.
(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:
<a href="/cdn-cgi/l/email-protection#71151e04165f0304151e1d0119311710105f161e07"><span class="__cf_email__" data-cfemail="f2969d8795dc8087969d9e829ab2949393dc959d84">[email protected]</span></a>.
(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 2024-0181R1,
dated September 24, 2024.
(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#febfba8dbe9b9f8d9fd09b8b8c918e9fd09b8b"><span class="__cf_email__" data-cfemail="8ecfcafdceebeffdefa0ebfbfce1feefa0ebfb">[email protected]</span></a>; website: easa.europa.eu. You may
find this EASA Emergency 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#066074286f6875766365726f6968466867746728616970"><span class="__cf_email__" data-cfemail="2d4b5f0344435e5d484e594442436d434c5f4c034a425b">[email protected]</span></a>.
Issued on February 18, 2025.
Victor Wicklund,
Deputy Director, Compliance & Airworthiness Division, Aircraft
Certification Service.
[FR Doc. 2025-02932 Filed 2-21-25; 8:45 am]
BILLING CODE 4910-13-P
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