DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2021-0999; Project Identifier MCAI-2021-00036-A]
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
for certain Pilatus Aircraft Ltd. (Pilatus) Model PC-12/47E 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 inward vent valves
installed during production without chromate conversion coating on the
bonding surface. This proposed AD would require modifying the inward
vent valves and prohibiting installation of unmodified inward vent
valves. The FAA is proposing this AD to address the unsafe condition on
DATES: The FAA must receive comments on this proposed AD by December
ADDRESSES: You may send comments, using the procedures found in
11.43 and 11.45, by any of the following methods:
Federal eRulemaking Portal: Go to https://www.regulations.gov. Follow
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; phone: +41 848 24 7 365;
email: email@example.com; website: 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.
Examining the AD Docket
You may examine the AD docket at https://www.regulations.gov by
searching for and locating Docket No. FAA-2021-0999; 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.
FOR FURTHER INFORMATION CONTACT: Doug Rudolph, Aviation Safety
Engineer, FAA, General Aviation & Rotorcraft Section, International
Validation Branch, 901 Locust, Room 301, Kansas City, MO 64106; phone:
(816) 329-4059; fax: (816) 329-4090; email: firstname.lastname@example.org.
The FAA invites you to send any written relevant data, views, or
arguments about this proposal. Send your comments to an address listed
under the ADDRESSES section. Include ``Docket No. FAA-2021-0999;
Project Identifier MCAI-2021-00036-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 NPRM 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 AD. 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
The European Union Aviation Safety Agency (EASA), which is the
Technical Agent for the Member States of the European Union, has issued
EASA AD 2021-0010, dated January 11, 2021 (referred to after this as
``the MCAI''), to correct an unsafe condition for Pilatus Model PC-12/
47E airplanes with serial number 1720 and serial number 2001 and
higher. The MCAI states:
An occurrence was reported where, on the production line, a
batch of inward vent valves without a chromate conversion coating on
the bonding surface were installed on some PC-12/47E aeroplanes.
Such inward vent valves are not in compliance with the latest
approved design data.
This condition, if not corrected, could lead to corrosion,
consequent degradation of the electrical bonding to Rib 16, and in
case of lightning strike, to arcing between the ungrounded equipment
and the primary structure, possibly resulting in a fire and reduced
control of the aeroplane.
To address this potential unsafe condition, Pilatus issued the
SB [Service Bulletin] to provide modification instructions.
For the reason described above, this [EASA] AD requires
modification of each affected part, as defined in this AD. This AD
also prohibits (re-) installation of affected parts.
You may examine the MCAI in the AD docket at https://www.regulations.gov
by searching for and locating Docket No. FAA-2021-0999.
Related Service Information Under 1 CFR Part 51
The FAA reviewed the following service documents proposed for
compliance with this NPRM:
Pilatus Service Bulletin No. 28-015, dated October 12, 2020, which
contains information for identifying the affected inward vent valves,
removing the affected inward vent valve, and installing a modified
inward vent valve.
Pall Corporation Service Bulletin SB9337-01-29-01, Issue 1, dated
September 22, 2020, which contains instructions for modifying the
inward vent valve by applying corrosion protective chromate
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.
This product has been approved by the aviation authority of another
country, and is approved for operation in the United States. Pursuant
to the FAA's bilateral agreement with this State of Design Authority,
it has notified the agency of the unsafe condition described in the
MCAI and service information 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
Proposed AD Requirements in This NPRM
This proposed AD would require accomplishing the actions specified
in the service information already described. This proposed AD would
also prohibit installation of the unmodified inward vent valves on any
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would
affect 24 airplanes of U.S. registry.
The FAA estimates the following costs to comply with this proposed
|Modification per airplane if
both sides affected
||3 work-hours x $85 per hour =
The FAA has included all known costs
in its 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.
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
(1) Would not be 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
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