DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0786; Project Identifier MCAI-2021-00429-A;
Amendment 39-21843; AD 2021-24-22]
RIN 2120-AA64

Airworthiness Directives; Pilatus Aircraft Ltd. Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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

SUMMARY: The FAA is superseding Airworthiness Directive (AD) 2012-06-
16, which applied to all Pilatus Aircraft Ltd. (Pilatus) Model PC-6,
PC-6-H1, PC-6-H2, PC-6/350, PC-6/350-H1, PC-6/350-H2, PC-6/A, PC-6/A-
H1, PC-6/A-H2, PC-6/B-H2, PC-6/B1-H2, PC-6/B2-H2, PC-6/B2-H4, PC-6/C-
H2, and PC-6/C1-H2 airplanes. AD 2012-06-16 required installing a new
rudder and elevator locking screw and modifying the installation of the
rudder and elevator hinge bolt. Since the FAA issued AD 2012-06-16, the
European Union Aviation Safety Agency (EASA) superseded its mandatory
continuing airworthiness information (MCAI) to correct an unsafe
condition on these products. This AD does not retain any actions
required by AD 2012-06-16 and requires inspecting and modifying the
rudder, elevator, and right-hand (RH) aileron hinge bolt installations.
The FAA is issuing this AD to address the unsafe condition on these
products.

DATES: This AD is effective January 25, 2022.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of January 25,
2022.

ADDRESSES: For service information identified in this final rule,
contact Pilatus Aircraft Ltd., Customer Support General Aviation, CH-
6371 Stans, Switzerland; phone: +41 848 247 365; email:
aircraft.com">techsupport.ch@pilatus-aircraft.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-2021-0786; 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, the
MCAI, 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 to supersede AD 2012-06-16, Amendment 39-16997 (77 FR
19061, March 30, 2012) (AD 2012-06-16). AD 2012-06-16 applied to all
Pilatus Model PC-6, PC-6-H1, PC-6-H2, PC-6/350, PC-6/350-H1, PC-6/350-
H2, PC-6/A, PC-6/A-H1, PC-6/A-H2, PC-6/B-H2, PC-6/B1-H2, PC-6/B2-H2,
PC-6/B2-H4, PC-6/C-H2, and PC-6/C1-H2 airplanes and required installing
a new elevator and rudder locking screw and modifying the installation
of the elevator and rudder hinge bolt. The NPRM published in the
Federal Register on September 17, 2021 (86 FR 51835).
The NPRM was prompted by AD 2021-0098, dated April 9, 2021
(referred to after this as ``the MCAI''), issued by EASA, which is the
Technical Agent for the Member States of the European Union. The MCAI
states:

Occurrences were reported where, on certain PC-6 aeroplanes, the
elevator or the rudders was lost or partially detached during
flight. All the occurrences happened on PC-6 aeroplanes in CONFIG 1.
This condition, if not corrected, could lead to in-flight
failure of the elevator or rudder attachment, possibly resulting in
reduced control of the aeroplane.
To address this potential unsafe condition, Pilatus issued SB
55-001 (original issue and Revision 1) to provide rework
instructions for the elevator and rudder hinge bolt locking.
Consequently, EASA published AD 2011-0230 to require this rework.
Subsequently, Pilatus issued recommended SB 55-003 (later revised)
to provide instructions to modify the hinge bolt installation of the
elevator and rudder. This [service bulletin] SB, being recommended
only, had no impact on the existing EASA AD.
Since that [EASA] AD and the recommended Pilatus SB 55-003 were
published, the latest risk assessment determined that the
modification of the hinge bolt installation of the elevator, rudder
and right-hand (RH) aileron installation must be required to reach
an acceptable level of safety for the affected aeroplanes.
Consequently, Pilatus issued the SB, as defined in this [EASA] AD,
to provide instructions to modify the affected aeroplanes into
CONFIG 2 standard.
For the reasons described above, this [EASA] AD supersedes EASA
AD 2011-0230 and requires, for certain aeroplanes, a one-time
inspection of the elevator and rudder installation, followed by
repetitive inspections of the elevator and rudder, and, depending on
findings, accomplishment of applicable corrective action(s). This
[EASA] AD also requires modification of the elevator, rudder and RH
aileron hinge bolt installations into CONFIG 2, which is the
terminating action for the repetitive inspections required by this
[EASA] AD. Finally, this [EASA] AD 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-2021-0786.

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
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 referenced above. The FAA reviewed the relevant
data and determined that air safety requires 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-6 Service Bulletin (SB) No. 55-005,
dated February 25, 2021 (Pilatus SB 55-005). The service information
specifies procedures for repetitively inspecting the hinge bolt
installations and taking any necessary corrective actions until the
hinge bolt is modified. Modifying the hinge bolt installation in
accordance with Pilatus SB 55-005 makes the airplane a CONFIG 2 design.
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.

Other Related Service Information

Pilatus also issued Pilatus PC-6 SB No. 55-003, dated November 29,
2013; Pilatus PC-6 SB No. 55-003, Revision 1, dated December 9, 2014;
Pilatus PC-6 SB No. 55-003, Revision 2, dated January 19, 2017; and
Pilatus PC-6 SB No. 55-003, Revision 3, dated November 6, 2017. This
service information specifies procedures for modifying the hinge bolt
installations, which makes the airplane a CONFIG 2 design. This service
information was superseded by Pilatus SB 55-005.

Costs of Compliance

The FAA estimates that this AD affects 50 airplanes of U.S.
registry.
The FAA estimates the following costs to comply with this AD:

Estimated Costs

The FAA estimates the following costs to do any necessary
corrective actions that would be required based on the results of the
mandated inspection. The FAA has no way of determining the number of
airplanes that might need these actions:

On-Condition 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

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:

a. Removing Airworthiness Directive AD 2012-06-16, Amendment 39-16997
(77 FR 19061, March 30, 2012); and

b. Adding the following new airworthiness directive: