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PROPOSED AD PILATUS AIRCRAFT LTD.: Docket No. FAA-2020-0885; Project Identifier MCAI-2020-00997-A.
(a) COMMENTS DUE DATE

    The FAA must receive comments  on this airworthiness directive (AD) by
    January 7, 2021.

(b) AFFECTED ADS

    None.

(c) APPLICABILITY

    This AD applies to Pilatus  Aircraft Ltd. PC-24 airplanes, all  serial
    numbers,  certificated  in any  category,  with any  of  the following
    evaporator filter assemblies installed, or if the part number (P/N) of
    the evaporator filter assembly is unknown:

(1) Cockpit filter assembly P/N 959.90.20.291 (PC24EC-6068-1);

(2) Cabin front filter assembly P/N 959.90.20.290 (PC24EC-6287-1);

(3) Cabin bottom filter assembly P/N 959.90.20.288 (PC24EC-6288-1); or

(4) Cabin top filter assembly P/N 959.90.20.289 (PC24EC-6297-1).

NOTE: The P/N in parenthesis is an alternative vendor P/N.

(d) SUBJECT

    Joint Aircraft System Component  (JASC)  Code  2100,  AIR CONDITIONING
    SYSTEM.

(e) UNSAFE CONDITION

    This  AD  was  prompted   by  a  reported  occurrence   where,  during
    production,  cockpit  and  cabin  evaporator  filters  produced   with
    degraded fire retardant properties were installed on some Model  PC-24
    airplanes. The FAA is issuing  this AD to detect improper  cockpit and
    cabin  evaporator  filters  installed on  Model  PC-24  airplanes. The
    unsafe  condition,  if not  addressed,  could result  in  filters with
    degraded fire retardant properties, resulting in smoke in the  cockpit
    and cabin in the event of electrical heater over- temperature.

(f) ACTIONS AND COMPLIANCE

(1) Within 4 months  after the effective date of this AD,  unless  already
    done, remove each filter assembly from service and replace with a fil-
    ter assembly as specified in table 1 to paragraph (f)(1) of this AD by
    following the Accomplishment Instructions,  sections 3A.  through 3C.,
    of Pilatus PC-24 Service Bulletin No. 21-006, dated April 3, 2020.

          TABLE 1 TO PARAGRAPH (F)(1)  EVAPORATOR FILTER ASSEMBLIES      
    ______________________________________________________________________
    ITEM                    REMOVE FILTER P/N      REPLACE WITH FILTER P/N
    ______________________________________________________________________
    Cockpit filter         P/N 959.90.20.291 or     P/N 959.90.20.303 or
    assembly               PC24EC-6068-1            PC24EC-6068-5

    Cabin front filter     P/N 959.90.20.290 or     P/N 959.90.20.304 or
    assembly               PC24EC-6287-1            PC24EC-6287-5

    Cabin bottom           P/N 959.90.20.288 or     P/N 959.90.20.305 or
    filter assembly        PC24EC-6288-1            PC24EC-6288-5

    Cabin top filter       P/N 959.90.20.289 or     P/N 959.90.20.306 or
    assembly               PC24EC-6297-1            PC24EC-6297-5
    ______________________________________________________________________

(2) As of the effective date of this AD, do not install an evaporator fil-
    ter assembly with a P/N listed in paragraph (c) of this AD on any air-
    plane.

(g) ALTERNATIVE METHODS OF COMPLIANCE (AMOCS)

    The Manager, General Aviation & Rotorcraft Section, International Val-
    idation Branch,  FAA,  has the authority to approve AMOCs for this AD,
    if requested using the procedures found in 14 CFR 39.19. Send informa-
    tion to ATTN: Doug Rudolph, Aerospace Engineer, FAA,  General Aviation
    & Rotorcraft Section,  International  Validation  Branch,  901 Locust,
    Room 301, Kansas City, Missouri 64106; telephone: (816) 329-4059; fax:
    (816) 329-4090; email: doug.rudolph@faa.gov. Before using any approved
    AMOC, notify your appropriate principal inspector,  or lacking a prin-
    cipal inspector,  the  manager  of the local flight standards district
    office/certificate holding district office.

(h) RELATED INFORMATION

    Refer to European Union Aviation Safety Agency (EASA) AD No. 2020-0160
    dated July 16, 2020, for more information. You may examine the EASA AD
    in the AD docket  on the internet  at  https://www.regulations.gov  by
    searching for and locating it in Docket No. FAA-2020-0885. For service
    information identified in this AD,  contact Pilatus Aircraft Ltd., CH-
    6371 Stans, Switzerland;telephone: +41 848 24 7 365;email:techsupport.
    ch@pilatus-aircraft.com;  internet: https://www.pilatus-aircraft.com/.
    You may review this referenced service information  at  the  FAA, Air-
    worthiness Products Section,  Operational Safety Branch,  901  Locust,
    Kansas City, Missouri 64106.  For  information  on the availability of
    this material at the FAA, call (816) 329-4148.

Issued  on  November 13, 2020.  Lance T. Gant, Director, Compliance & Air-
worthiness Division, Aircraft Certification Service.

DATES: The FAA must receive comments  on this  proposed AD  by  January 7,
2021.
PREAMBLE 

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-0885; Project Identifier MCAI-2020-00997-A]
RIN 2120-AA64

Airworthiness Directives; Pilatus Aircraft Ltd. Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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

SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD)
for certain Pilatus Aircraft Ltd. (Pilatus) Model PC-24 airplanes. This
proposed AD results from 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 improperly manufactured cockpit
and cabin evaporator filters installed during production on some PC-24
airplanes. The FAA is proposing this AD to address the unsafe condition
on these products.

DATES: The FAA must receive comments on this proposed AD by January 7,
2021.

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 https://www.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.

For service information identified in this NPRM, contact
Pilatus Aircraft Ltd., CH-6371 Stans, Switzerland; telephone: +41 848
24 7 365; email: techsupport.ch@pilatus-aircraft.com; internet: https://
www.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 816-329-4148. It is also available on
the internet at https://www.regulations.gov by searching for and
locating Docket No. FAA-2020-0885.

Examining the AD Docket

You may examine the AD docket on the internet at https://www.regulations.
gov by searching for and locating Docket No. FAA-2020-0885;
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. Comments will be
available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT: Doug Rudolph, Aerospace Engineer, FAA,
General Aviation & Rotorcraft Section, International Validation Branch,
901 Locust, Room 301, Kansas City, Missouri 64106; telephone: (816)
329-4059; fax: (816) 329-4090; 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-2020-0885; Project Identifier
MCAI-2020-00997-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
https://www.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, Aerospace Engineer, FAA, General Aviation & Rotorcraft
Section, International Validation Branch, 901 Locust, Room 301, Kansas
City, Missouri 64106; telephone: (816) 329-4059; fax: (816) 329-4090;
email: doug.rudolph@faa.gov. 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 Community, has
issued EASA AD 2020-0160, dated July 16, 2020 (referred to after this
as "the MCAI"), to address the unsafe condition on Pilatus Model PC-
24 airplanes. The MCAI states:

An occurrence was reported where, during production, cockpit and
cabin evaporator filters were installed on some PC-24 aeroplanes,
which were not the proper parts for the affected configuration.

This condition, if not corrected, could degrade the fire
retardant properties of the filters, possibly resulting in an
increase in smoke in the cockpit/cabin in case of electrical heater
over-temperature.

To address this potential unsafe condition, Pilatus issued the
[service bulletin] SB to provide replacement instructions.

For the reason described above, this AD requires replacement of
affected parts with serviceable parts, as defined in this [EASA] AD,
and prohibits (re) installation of affected parts.

Due to a quality escape, the fire retardant used in the original
filters installed in production is not sufficient for the conditions in
this configuration, which is close to the heater and blowers.

You may obtain further information by examining the MCAI in the AD
docket on the internet at https://www.regulations.gov by searching for
and locating Docket No. FAA-2020-0885.

Related Service Information Under 1 CFR Part 51

The FAA reviewed Pilatus PC-24 Service Bulletin No. 21-006, dated
April 3, 2020. The service information specifies procedures to replace
the cockpit and cabin evaporator filters with new filters contained in
a modification kit. 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 the ADDRESSES section.

FAA's Determination and Requirements of the Proposed AD

This product has been approved by the aviation authority of another
country and is approved for operation in the United States. Pursuant to
our bilateral agreement with this State of Design Authority, it has
notified the FAA of the unsafe condition described in the MCAI and
service information referenced above. The FAA is proposing this AD
because the FAA determined the unsafe condition exists and is likely to
exist or develop on other products of the same type design.

Differences Between This Proposed AD and the MCAI

This proposed AD would apply to airplanes with a defective filter
installed, whereas the EASA AD applies to airplanes that do not have
the modification kit, which was installed in production. The proposed
AD identifies the individual part numbers (P/Ns) of the defective
filters to address any airplanes that may have had a modification kit
filter replaced with a defective filter in the field before this
proposed AD becomes effective. The proposed AD would also apply to
airplanes with a filter where the P/N is unknown. Pilatus advises that
the defective filters can only be identified by their packing
documents, as they do not have a permanent P/N marked on the actual
part. The new filters in the modification kit do have a permanent
marking on the frame of the actual part.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would
affect 36 airplanes of U.S. registry. The FAA also estimates that it
would take 2.5 work-hours per product to comply with the requirements
of this proposed AD. The average labor rate is $85 per work-hour.
Required parts would cost about $575 per product, if all 4 filters
would need to be replaced.

Based on these figures, the FAA estimates the cost of this proposed
AD on U.S. operators to be $28,350, or $787.50 per product.

The FAA has included all costs in this cost estimate. According to
the manufacturer, however, some of the costs of this proposed 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 this proposed
regulation:

(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 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: