DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2024-0045; Project Identifier MCAI-2023-01088-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)
2023-12-17, which applies to Pilatus Aircraft Ltd. (Pilatus) Model PC-
12, PC-12/45, PC-12/47, and PC-12/47E airplanes. AD 2023-12-17 requires
revising the airworthiness limitation section (ALS) of the existing
aircraft maintenance manual (AMM) or Instructions for Continued
Airworthiness (ICA) for your airplane by introducing new and more
restrictive instructions and maintenance tasks as specified in the
component limitations section, which includes repetitive inspections
for cracks in the lower main spar connection of the horizontal
stabilizer. Since the FAA issued AD 2023-12-17, the FAA has determined
that new or more restrictive airworthiness limitations are necessary.
This proposed AD would require revising the ALS of your existing AMM or
ICA and your existing approved maintenance or inspection program, as
applicable, 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.

DATES: The FAA must receive comments on this NPRM by March 18, 2024.

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-2024-0045; 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 EASA material identified in this NPRM, contact EASA,
Konrad-Adenauer-Ufer 3, 50668 Cologne, Germany; phone: +49 221 8999
000; email: ADs@easa.europa.eu; website: easa.europa.eu. You may find
this material on the EASA website at ad.easa.europa.eu.
You may view this service information 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: doug.rudolph@faa.gov.

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-2024-0045; Project Identifier
MCAI-2023-01088-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
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

The FAA issued AD 2023-12-17, Amendment 39-22475 (88 FR 42604, July
3, 2023) (AD 2023-12-17), for Pilatus Model PC-12, PC-12/45, PC-12/47,
and PC-12/47E airplanes. AD 2023-12-17 was prompted by MCAI originated
by EASA, which is the Technical Agent for the Member States of the
European Union. EASA issued AD 2022-0103, dated June 9, 2022 (EASA AD
2022-0103) to correct an unsafe condition for Pilatus Model PC-12, PC-
12/45, PC-12/47, and PC-12/47E airplanes identified as cracks in the
lower main spar connection of the horizontal stabilizer and the failure
of certain parts.
AD 2023-12-17 requires incorporating new revisions to the ALS
of the existing AMM or ICA for your airplane to establish new or more
restrictive airworthiness limitations that include repetitive
inspections for cracks in the lower main spar connection of the
horizontal stabilizer. The FAA issued AD 2023-12-17 to address cracks
in the lower main spar connection of the horizontal stabilizer and
failure of certain parts, which could result in loss of airplane
control.

Actions Since AD 2023-12-17 Was Issued

Since the FAA issued AD 2023-12-17, EASA superseded EASA AD 2022-
0103 and issued EASA AD 2023-0184, dated October 19, 2023 (EASA AD
2023-0184) (also referred to as the MCAI) for all Pilatus Model PC-12,
PC-12/45, PC-12/47, and PC-12/47E airplanes. The MCAI states that new
or more restrictive tasks and limitations have been developed. These
new or more restrictive airworthiness limitations include repetitive
eddy current inspections for cracks in the main landing gear yoke
fitting. The FAA is issuing this AD to address failure of certain
parts, which could result in asymmetric main landing gear failure that
could lead to loss of airplane control during take-off, landing, and
taxiing operations Additionally, the actions required to address the
unsafe condition in AD 2023-12-17 are included in ``the applicable
ALS,'' as defined in EASA AD 2023-0184.
You may examine the MCAI in the AD docket at regulations.gov under
Docket No. FAA-2024-0045.

Related Service Information Under 1 CFR Part 51

EASA AD 2023-0184 requires certain actions and associated
thresholds and intervals, including life limits and maintenance tasks.
EASA AD 2023-0184 also requires doing corrective actions if any
discrepancy (as defined in ``the applicable ALS'' as defined in EASA AD
2023-0184) is found during accomplishment of any task required by
paragraph (1) of EASA AD 2023-0184 and revising the aircraft
maintenance program (AMP) by incorporating the limitations, tasks, and
associated thresholds and intervals described in ``the applicable ALS''
as defined in EASA AD 2023-0184. 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 ADDRESSES.

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 the State of Design
Authority, it has notified the FAA of the unsafe condition described in
the MCAI described above. The FAA is issuing this NPRM after
determining that the unsafe condition described previously is likely to
exist or develop in 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-
12-17. This proposed AD would require revising the ALS of the existing
AMM or ICA for your airplane as specified in EASA AD 2023-0184,
described previously, except as discussed under ``Differences Between
this Proposed AD and EASA AD 2023-0184.''

Differences Between This Proposed AD and EASA AD 2023-0184

Paragraph (1) of EASA AD 2023-0184 requires replacing each
component before exceeding the applicable life limit and within the
identified thresholds and intervals accomplishing all applicable
maintenance tasks as specified in the applicable ALS for that airplane.
Paragraph (2) of EASA AD 2023-0184 requires corrective actions in
accordance with the applicable Pilatus maintenance documentation or
contacting Pilatus for approved instructions and accomplishing those
instructions accordingly. Paragraph (4) of EASA AD 2023-0184 provides
credit for performing actions in accordance with previous revisions of
the Pilatus AMM. Paragraph (5) of EASA AD 2023-0184 explains that after
revision of the AMP, it is not necessary to record accomplishment of
individual actions for demonstration of AD compliance. This proposed AD
would not require compliance with paragraphs (1), (2), (4), and (5) of
EASA AD 2023-0184.

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 civil aviation
authority (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 2023-0184 by reference in the FAA
final rule. Service information required by the EASA AD for compliance
will be available at regulations.gov by searching for and locating
Docket No. FAA-2024-0045 after the FAA final rule is published.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would
affect 1,030 airplanes of U.S. registry.
The FAA estimates the following costs to comply with this AD:

Estimated Costs

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

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]

2. The FAA amends Sec. 39.13 by:

a. Removing Airworthiness Directive 2023-12-17, Amendment 39-22475 (88
FR 42604, July 3, 2023); and

b. Adding the following new AD: