DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2023-0421; Project Identifier MCAI-2022-01360-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 adopt a new airworthiness directive (AD)
for certain Pilatus Aircraft Ltd. (Pilatus) Model PC-12, PC-12/45, PC-
12/47, and PC-12/47E airplanes. This proposed AD was prompted by
mandatory continuing airworthiness information (MCAI) originated by an
aviation authority of another country to identify and correct an unsafe
condition on an aviation product. The MCAI identifies the unsafe
condition as insufficient grounding of the vapor cycle cooling system
(VCCS) compressor/condenser. This proposed AD would require inspecting
the power return and chassis grounding cable attachment points at frame
37, including the attachment parts, and depending on the inspection
results, corrective action. This proposed AD would also require
modifying the installation of the VCCS compressor/condenser power
return cables and installing an additional isolated VCCS chassis ground
cable. 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 13, 2023.

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-2023-0421; 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 MCAI, any comments received, and other
information. The street address for Docket Operations is listed above.
Material Incorporated by Reference:
For service information identified in this NPRM, contact
Pilatus Aircraft Ltd., Customer Support General Aviation, CH-6371
Stans, Switzerland; phone: +41 848 24 7 365; email:
aircraft.com">techsupport.ch@pilatus-aircraft.com; website: pilatus-aircraft.com.
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, General Aviation & Rotorcraft Section, International
Validation Branch, FAA, 901 Locust, Room 301, Kansas City, MO 64106;
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-2023-0421; Project Identifier
MCAI-2022-01360-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
this 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, General Aviation & Rotorcraft
Section, International Validation Branch, 901 Locust, Room 301, Kansas
City, MO 64106. 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 European Union Aviation Safety Agency (EASA), which is the
Technical Agent for the Member States of the European Union, has issued
EASA AD 2022-0212, dated October 18, 2022 (referred to after this as
``the MCAI''), to correct an unsafe condition on certain serial-
numbered Pilatus Model PC-12, PC-12/45, PC-12/47, and PC-12/47E
airplanes.
The MCAI was prompted by a reported occurrence of a burning odor
coming from the air conditioning vents during the climb phase of a
Pilatus Model PC-12/47E airplane. An investigation identified that
insufficient grounding of the VCCS compressor/condenser at frame 37
resulted in severe heat damage to the baseplate and adjacent metal
support structure. It was determined that this condition may occur on
airplanes equipped in production with the large oxygen bottle installed
on the right-hand side of the rear fuselage.
To address the unsafe condition, the MCAI requires a one-time
inspection of the power return and chassis grounding cable attachment
point at frame 37, including the attachment parts, and modification of
the installation of the VCCS.
This condition, if not addressed, could, in the case of damage to
the oxygen supply line, lead to an uncontrolled fire with damage to the
airplane and injury to the occupants.
You may examine the MCAI in the AD docket at regulations.gov under
Docket No. FAA-2023-0421.

Related Service Information Under 1 CFR Part 51

The FAA reviewed Pilatus PC-12 Service Bulletin 21-016, dated
August 15, 2022, which specifies procedures for inspecting the power
return and chassis grounding cable attachment point on the airframe at
frame 37, including the attachment parts, modifying the installation of
the VCCS compressor/condenser power return cables, and installing an
additional isolated VCCS chassis ground cable. This service bulletin
also specifies contacting Pilatus if any damage is found.
This service information 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 this State of Design
Authority, it has notified the FAA of the unsafe condition described in
the MCAI and service information described 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 these
same type designs.

Proposed AD Requirements in This NPRM

This proposed AD would require accomplishing the actions specified
in the MCAI, except as discussed under ``Differences Between this
Proposed AD and the MCAI.''

Differences Between This Proposed AD and the MCAI

The MCAI requires contacting the manufacturer for approved
corrective action instructions if any discrepancy is found during the
inspection. This proposed AD would require contacting either the
Manager, International Validation Branch, FAA; or EASA; or Pilatus's
EASA Design Organization Approval (DOA). If approved by the DOA, the
approval must include the DOA-authorized signature.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would
affect 8 airplanes of U.S. registry.
The FAA estimates the following costs to comply with this proposed
AD:

Estimated Costs

The repair instructions that may be needed as a result of the
inspection could vary significantly from airplane to airplane. The FAA
has no data to determine the costs to accomplish the repair or the
number of airplanes that would need this repair.

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 this 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 adding the following new airworthiness
directive: