DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-1074; Project Identifier MCAI-2020-01257-A;
Amendment 39-21574; AD 2021-11-12]
RIN 2120-AA64

Airworthiness Directives; Pilatus Aircraft Ltd. Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for
certain Pilatus Aircraft Ltd. (Pilatus) Model PC-24 airplanes. This 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 the engine attachment hardware not
conforming to the approved design, which could affect the structural
integrity of the airplane. This AD requires inspecting the engine
attachment hardware for missing washers and loose nuts and taking
corrective actions as necessary. The FAA is issuing this AD to address
the unsafe condition on these products.

DATES: This AD is effective July 15, 2021.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of July 15,
2021.

ADDRESSES: For service information identified in this final rule,
contact Pilatus Aircraft Ltd., CH-6371, Stans, Switzerland; phone: +41
848 24 7 365; email: atus-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 at https://www.regulations.gov by searching for and
locating Docket No. FAA-2020-1074.

Examining the AD Docket

You may examine the AD docket at https://www.regulations.gov by
searching for and locating Docket No. FAA-2020-1074; 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 final rule, any
comments received, and other information. The address for Docket
Operations is U.S. Department of Transportation, Docket Operations, M-
30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue
SE, Washington, DC 20590.

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: doug.rudolph@faa.gov.

SUPPLEMENTARY INFORMATION:

Background

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14
CFR part 39 by adding an AD that would apply to certain serial-numbered
Pilatus Model PC-24 airplanes. The NPRM published in the Federal
Register on March 26, 2021 (86 FR 16124). The NPRM was prompted by MCAI
originated by the European Union Aviation Safety Agency (EASA), which
is the Technical Agent for the Member States of the European Union.
EASA has issued EASA AD 2020-0194, dated September 8, 2020 (referred to
after this as ``the MCAI''), to address an unsafe condition on certain
serial-numbered Pilatus Model PC-24 airplanes. The MCAI states:

During a scheduled maintenance inspection, the engine attachment
hardware of a PC-24 airplane was found not to conform to the
approved design. A washer was missing beneath each of the four
mating bolt heads on the rear engine beam. In addition, some of the
keeper fitting attachment bolts on the LH/RH middle inner nacelle
were found with loose nuts. It was also determined that other
aeroplanes may have the same non-conformities.
This condition, if not detected and corrected, could damage the
engine attachment hardware, possibly affecting the structural
integrity of the aeroplane.
To address this potential unsafe condition, Pilatus issued the
[service bulletin] SB, providing instructions for inspection and
corrective action.
For the reason described above, this [EASA] AD requires a one-
time inspection for missing washers and loose nuts on the engine
attachment hardware and, depending on findings, the accomplishment
of applicable corrective action(s).

You may examine the MCAI in the AD docket at https://www.regulations.gov
by searching for and locating Docket No. FAA-2020-1074.
In the NPRM, the FAA proposed to require inspecting the engine
attachment hardware for missing washers and loose nuts and taking
corrective actions as necessary. The FAA is issuing this AD to address
the unsafe condition on this product.

Discussion of Final Airworthiness Directive

Comments

The FAA received no comments on the NPRM or on the determination of
the costs.

Conclusion

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 reviewed the relevant
data and determined that air safety and the public interest require
adopting this AD as proposed. Accordingly, the FAA is issuing this AD
to address the unsafe condition on these products. This AD is adopted
as proposed in the NPRM.

Related Service Information Under 1 CFR Part 51

The FAA reviewed Pilatus PC-24 Service Bulletin No. 71-001, dated
June 30, 2020. This service information specifies procedures for
inspecting the engine attachment hardware for loose nuts and missing
washers and taking corrective actions depending on findings. 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.

Costs of Compliance

The FAA estimates that this AD affects 34 airplanes of U.S.
registry.
The FAA estimates that it would take 2.5 work-hours to do the one-
time inspections. The average labor rate is $85 per work-hour.
Based on these figures, the FAA estimates the cost of this AD on
U.S. operators would be $7,225 or $212.50 per airplane.
The FAA also estimates that, as on-condition costs, installing
missing washers, replacing bolts, and doing an eddy current inspection
of the bolt holes would take 4.5 work-hours and require parts costing
$200 for a cost of $582.50 per airplane. This estimate assumes
replacing all of the rear engine beam attachment bolts and washers and
doing an eddy current inspection of all the attachment bolt holes. If
the bolt holes are found damaged during the eddy current inspection,
the damage will vary considerably from airplane to airplane, and the
FAA has no way of estimating a repair cost. In addition, the FAA has no
way of determining the number of airplanes that might need these
actions.
The FAA has included all known costs in this cost estimate.
According to the manufacturer, however, some of the costs of this 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

This AD will not have federalism implications under Executive Order
13132. This AD will 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 this AD:
(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 Amendment

Accordingly, under the authority delegated to me by the
Administrator, the FAA amends 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: