DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2017-0452; Product Identifier 2017-NE-14-AD; Amendment
39-19050; AD 2017-19-20]
RIN 2120-AA64

Airworthiness Directives; General Electric Company Turboshaft
Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: We are adopting a new airworthiness directive (AD) for certain
General Electric Company (GE) CT7-8A and CT7-9B model turboshaft
engines. This AD was prompted by reports from the manufacturer that the
high-pressure compressor (HPC) impeller installed on these engines may
have suffered from material degradation during the manufacturing
process. This AD requires removal of the affected HPC impellers. We are
issuing this AD to address the unsafe condition on these products.

DATES: This AD is effective October 27, 2017.

ADDRESSES: For service information identified in this final rule,
contact General Electric Company, GE-Aviation, Room 285, 1 Neumann Way,
Cincinnati, OH 45215; phone: 513-552-3272; fax: 513-552-3329; email:
geae.aoc@ge.co. You may view this service information at the FAA,
Engine and Propeller Standards Branch, 1200 District Avenue,
Burlington, MA. For information on the availability of this material at
the FAA, call 781-238-7125. It is also available on the internet at
http://www.regulations.gov by searching for and locating Docket No.
FAA-2017-0452.

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.
gov by searching for and locating Docket No. FAA-2017-
0452; or in person at the Docket Management Facility between 9 a.m. and
5 p.m., Monday through Friday, except Federal holidays. The AD docket
contains this final rule, the regulatory evaluation, any comments
received, and other information. The address for the
Docket Office (phone: 800-647-5527) is Document Management Facility,
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: Kasra Sharifi, Aerospace Engineer, ECO
Branch, FAA, 1200 District Avenue, Burlington, MA 01803; phone: 781-
238-7773; fax: 781-238-7199; email: kasra.sharifi@faa.gov.

SUPPLEMENTARY INFORMATION:

Discussion

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR
part 39 by adding an AD that would apply to certain GE CT7-8A and CT7-
9B model turboshaft engines. The NPRM published in the Federal Register
on June 16, 2017 (82 FR 27634). The NPRM was prompted by reports from
the manufacturer that the HPC impeller installed on these engines may
have suffered from material degradation during the manufacturing
process. The NPRM proposed to require removal of the affected HPC
impellers. We are issuing this AD to prevent failure of the HPC
impeller, uncontained HPC impeller release, damage to the engine, and
damage to the airplane/helicopter.

Comments

We gave the public the opportunity to participate in developing
this final rule. We received no comments on the NPRM or on the
determination of the cost to the public.

Conclusion

We reviewed the relevant data and determined that air safety and
the public interest require adopting this final rule as proposed.

Related Service Information

We reviewed GE Service Bulletin (SB) CT7-TP S/B 72-0524, dated June
16, 2016. The SB describes procedures for replacing the affected HPC
impellers.

Costs of Compliance

We estimate that this AD affects 1 engine installed on a helicopter
of U.S. registry.
We estimate 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.
We are 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 engines, propellers, and
appliances to the Manager, Engine and Propeller Standards Branch,
Policy and Innovation Division.

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) Is not a ``significant rule'' under DOT Regulatory Policies and
Procedures (44 FR 11034, February 26, 1979),
(3) Will not affect intrastate aviation in Alaska to the extent
that it justifies making a regulatory distinction, 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):