DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-0471; Project Identifier MCAI-2019-00126-E;
Amendment 39-21226; AD 2020-18-05]
RIN 2120-AA64

Airworthiness Directives; Pratt & Whitney Canada Corp. Turboshaft
Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all
Pratt & Whitney Canada Corp. (P&WC) PT6B-37A model turboshaft engines
with engine serial number PCE-PU0289 and earlier. This AD was prompted
by a report of contamination from galvanic corrosion between the fuel
control unit (FCU) aluminum body and the steel union fitting causing
the loss of engine control, resulting in an engine over-speed condition
and subsequent in-flight shutdown (IFSD). This AD requires replacing
the FCU with a part eligible for installation. The FAA is issuing this
AD to address the unsafe condition on these products.

DATES: This AD is effective October 7, 2020.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of October 7,
2020.

ADDRESSES: For service information identified in this final rule,
contact Pratt & Whitney Canada Corp., 1000 Marie-Victorin, Longueuil,
Quebec, Canada, J4G 1A1; phone: 800-268-8000; fax: 450-647-2888;
website: https://www.pwc.ca/en/. You may view this service information
at the FAA, Airworthiness Products Section, Operational Safety Branch,
1200 District Avenue, Burlington, MA 01803. For information on the
availability of this material at the FAA, call 781-238-7759. It is also
available on the internet at https://www.regulations.gov by searching
for and locating Docket No. FAA-2020-0471.

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-
0471; 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 mandatory continuing airworthiness information
(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: Mehdi Lamnyi, Aerospace Engineer, ECO
Branch, FAA, 1200 District Avenue, Burlington, MA 01803; phone: 781-
238-7743; fax: 781-238-7199; email: Mehdi.Lamnyi@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 all P&WC PT6B-37A model
turboshaft engines with engine serial number PCE-PU0289 and earlier.
The NPRM published in the Federal Register on May 14, 2020 (85 FR
28888). The NPRM was prompted by a report of contamination from
galvanic corrosion between the FCU aluminum body and the steel union
fitting causing the loss of engine control, resulting in an engine
over-speed condition and subsequent IFSD. The NPRM proposed to require
replacing the FCU with a part eligible for installation. The FAA is
issuing this AD to address the unsafe condition on these products.
Transport Canada Civil Aviation (Transport Canada), which is the
aviation authority for Canada, has issued Transport Canada AD CF-2019-
05, dated February 19, 2019 (referred to after this as ``the MCAI''),
to address the unsafe condition on these products. The MCAI states:

There has been one reported incident on a PT6B-37A engine, where
the contamination from galvanic corrosion between the FCU aluminum
body and the steel union fitting has caused the loss of engine
control, resulting in an engine over-speed condition and
subsequently leading to an engine inflight shutdown (IFSD). This
condition, if not corrected, could lead to additional cases of
IFSDs, which on a single engine helicopter may result in an
emergency autorotation landing. To address the subject galvanic
corrosion problem in the FCU, P&WC has issued Service Bulletin (SB)
39107 to replace the affected FCUs with a modified FCU that is not
susceptible to the subject galvanic corrosion problem. This
[Transport Canada] AD mandates compliance with P&WC SB 39107,
requiring the replacement of the affected FCUs to mitigate the
potential unsafe condition.

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-2020-0471.

Comments

The FAA gave the public the opportunity to participate in
developing this final rule. The FAA has considered the comment
received. An individual commenter supported the NPRM.

Conclusion

The FAA reviewed the relevant data, considered the comments
received, and determined that air safety and the public interest
require adopting this final rule as proposed except for minor editorial
changes. The FAA has determined that these minor changes:
Are consistent with the intent that was proposed in the
NPRM for addressing the unsafe condition; and
Do not add any additional burden upon the public than was
already proposed in the NPRM.

Service Information Incorporated by Reference Under 1 CFR Part 51

The FAA reviewed P&WC Service Bulletin (SB) No. PT6B-72-39107,
Revision No. 1, dated December 13, 2017. The SB describes procedures
for replacing the FCU. 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 affects 75 engines installed on
helicopters of U.S. registry.
The FAA estimates the following costs to comply with this AD:

Estimated 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 this AD:
(1) Is not 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
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 (AD):