DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2018-1058; Product Identifier 2018-CE-051-AD; Amendment
39-19646; AD 2019-10-07]
RIN 2120-AA64

Airworthiness Directives; Pilatus Aircraft Ltd. Airplanes

AGENCY: Federal Aviation Administration (FAA), Department of
Transportation (DOT).

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for
Pilatus Aircraft Ltd. Models PC-6, 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, PC-6/C1-H2, PC-6-H1, and PC-6-H2 airplanes. This AD
results from mandatory continuing airworthiness information (MCAI)
issued by an aviation authority of another country to identify and
correct an unsafe condition on an aviation product. The MCAI describes
the unsafe condition as sheared or missing rivets on the horizontal
stabilizer hinge bracket assemblies. The FAA is issuing this AD to
require actions to address the unsafe condition on these products.

DATES: This AD is effective July 10, 2019.
The Director of the Federal Register approved the incorporation by
reference of certain publications listed in the AD as of July 10, 2019.

ADDRESSES: You may examine the AD docket on the internet at http://
www.regulations.gov by searching for and locating Docket No. FAA-2018-
1058; or in person at Docket Operations, 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 service information identified in this AD, contact PILATUS
Aircraft Ltd., Customer Technical Support (MCC), P.O. Box 992, CH-6371
Stans, Switzerland; phone: +41 (0)41 619 67 74; fax: +41 (0)41 619 67
73; email: aircraft.com">techsupport@pilatus-aircraft.com; internet: http://
www.pilatus-aircraft.com. You may view this referenced service
information at the FAA, Policy and Innovation Division, 901 Locust,
Kansas City, Missouri 64106. For information on the availability of
this material at the FAA, call (816) 329-4148. It is also available on
the internet at http://www.regulations.gov by searching for Docket No.
FAA-2018-1058.

FOR FURTHER INFORMATION CONTACT: Doug Rudolph, Aerospace Engineer, FAA,
Small Airplane Standards Branch, 901 Locust, Room 301, Kansas City,
Missouri 64106; telephone: (816) 329-4059; fax: (816) 329-4090; email:
doug.rudolph@faa.gov.

SUPPLEMENTARY INFORMATION:

Discussion

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14
CFR part 39 by adding an AD that would apply to Pilatus Aircraft Ltd.
Models PC-6, 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, PC-6/
C1-H2, PC-6-H1, and PC-6-H2 airplanes. The NPRM was published in the
Federal Register on December 26, 2018 (83 FR 66175). The NPRM proposed
to correct an unsafe condition for the specified products and was based
on MCAI AD No. 2018-0217, dated October 10, 2018, issued by the
European Aviation Safety Agency (EASA), which is the Technical Agent
for the Member States of the European Community. The MCAI states:

During a routine inspection, the rivets of the hinge bracket
assemblies on a Pilatus PC-6 were found to be sheared or missing.
Investigation results identified that this was most likely due to
application of too much force to the ends of the horizontal
stabilizer during ground handling.
This condition, if not detected and corrected, could lead to
failure of the primary horizontal stabilizer load path and
consequent separation of the horizontal stabilizer, possibly
resulting in loss of control of the aeroplane.
To address this potential unsafe condition, Pilatus Aircraft Ltd
issued the SB [service bulletin] to provide applicable inspection
instructions.
For the reasons described above, this [EASA] AD requires a one-
time inspection of the affected parts and the horizontal stabilizer
front spar attachment area and, depending on findings,
accomplishment of applicable corrective action(s). This [EASA] AD
also requires, before installation, inspection of, and, depending on
findings, corrective action(s) on, affected parts held as spare.

The amount of force to the ends of the horizontal stabilizer cannot
be quantified; however, fleet experience shows that repetitive pushing
or pulling on the horizontal stabilizer to move the airplane on the
ground can overload the rivets. Although a root cause could not be
determined, due to the severity of separation of a horizontal
stabilizer, EASA determined that the corrective actions should be
required for other airplanes of the same type design.
Pilatus Aircraft Ltd. had previously considered the small size of
the original ``DO NOT PUSH'' markings and the significant chance of the
markings being over-sprayed during a respray. As a result, Pilatus
Aircraft Ltd. issued a service bulletin to specify replacing the
smaller markings with new, larger placards. The FAA requires installing
these placards in this AD.
The MCAI can be found in the AD docket on the internet at https://www.regulations.gov/document?D=FAA-2018-1058-0002.

Comments

The FAA gave the public the opportunity to participate in
developing this AD. The following presents the comment received on the
proposal and the FAA's response the comment.

Request To Add Omitted Section to Required Procedures

Pilatus Aircraft Ltd. requested that the FAA amend the required
actions to include section H of the Accomplishment Instructions in
Pilatus Aircraft Ltd. PC-6 Service Bulletin No. 55-004, dated July 2,
2018. The commenter notes that section H was omitted and should be
added to the final rule.
The FAA agrees with the commenter and has changed paragraph
(f)(1)(i) to include section H.

Conclusion

The FAA reviewed the relevant data, considered the comment
received, and determined that air safety and the public interest
require adopting the AD with the change described previously. The FAA
determined that this change is consistent with the intent that was
proposed in the NPRM for correcting the unsafe condition and does not
add any additional burden upon the public than was already proposed in
the NPRM. The FAA also determined that this change will not increase
the economic burden on any operator or increase the scope of the AD.

Related Service Information Under 1 CFR Part 51

Pilatus Aircraft Ltd. has issued PC-6 Service Bulletin No. 55-004,
dated July 2, 2018. The service information contains procedures for
inspecting the left-hand and right-hand horizontal stabilizer hinge
bracket assemblies and, if any discrepancies are found, repairing or
replacing any damaged rivets and screws. Pilatus Aircraft Ltd. has also
issued PC-6 Service Bulletin No. 55-002, Revision. No. 1, dated
February 18, 2016. This service information contains procedures for
inspecting and repairing the horizontal stabilizer attachment hardware
and installing four ``DO NOT PUSH'' placards. 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.

Costs of Compliance

The FAA estimates that this AD will affect 30 products of U.S.
registry. The FAA also estimates that it will take about 9 work-hours
per product to comply with the inspection and placard requirements of
this AD. The average labor rate is $85 per work-hour. Required parts
will cost about $200 per product.
Based on these figures, the FAA estimates the cost of the
inspection and placard requirements on U.S. operators to be $28,950, or
$965 per product.
In addition, the FAA estimates the following to do any necessary
follow-on actions: Each rivet replacement will take 2 work-hours,
fastener replacement will take 3 work-hours, one hinge bracket assembly
replacement will take 9 work-hours, and two hinge bracket assembly
replacements will take 15 work-hours. The total estimated cost of parts
will be $10,000. The FAA has no way of determining the number of
products that may need replacement.

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.
This AD is issued in accordance with authority delegated by the
Executive Director, Aircraft Certification Service, as authorized by
FAA Order 8000.51C. In accordance with that order, issuance of ADs is
normally a function of the Compliance and Airworthiness Division, but
during this transition period, the Executive Director has delegated the
authority to issue ADs applicable to small airplanes, gliders,
balloons, airships, domestic business jet transport airplanes, and
associated appliances to the Director of the Policy and Innovation
Division.

Regulatory Findings

The FAA determined that 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 this AD:
(1) Is not a ``significant regulatory action'' under Executive
Order 12866,
(2) Is not a ``significant rule'' under the DOT Regulatory Policies
and Procedures (44 FR 11034, February 26, 1979),
(3) Will not affect intrastate aviation in Alaska, and
(4) 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.

Adoption of 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 (AD):