DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2017-0658; Product Identifier 2017-NE-20-AD; Amendment
39-19195; AD 2018-03-22]
RIN 2120-AA64

Airworthiness Directives; GE Aviation Czech s.r.o. Turboprop Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: We are adopting a new airworthiness directive (AD) for GE
Aviation Czech s.r.o. M601D-11, M601E-11, M601E-11A, M601E-11AS, M601E-
11S, and M601F turboprop engines. This AD requires removal of certain
power turbine (PT) disks installed on the affected engines. This AD was
prompted by a design review by the manufacturer that determined PT
rotors with certain disks have less overspeed margin than originally
stated during product certification. We are issuing this AD to address
the unsafe condition on these products.

DATES: This AD is effective March 21, 2018.

ADDRESSES: For service information identified in this final rule,
contact GE Aviation Czech s.r.o., Beranovych 65, 199 02 Praha
9--Letnany, Czech Republic; phone: +420 222 538 111; fax: +420
222 538 222. You may view this service information at the FAA, Engine &
Propeller Standards Branch, 1200 District Avenue, Burlington, MA. For
information on the availability of this material at the FAA, call 781-
238-7759.

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-
0658; 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 AD, the mandatory continuing airworthiness information
(MCAI), 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: Robert Green, Aerospace Engineer, ECO
Branch, FAA, 1200 District Avenue, Burlington, MA 01803; phone: 781-
238-7754; fax: 781-238-7199; email: robert.green@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 GE Aviation Czech s.r.o.
M601D-11, M601E-11, M601E-11A, M601E-11AS, M601E-11S, and M601F
turboprop engines. The NPRM published in the Federal Register on
September 22, 2017 (82 FR 44355). The NPRM was prompted by a design
review by the manufacturer that determined PT rotors with certain disks
have less overspeed margin than originally stated during product
certification. The NPRM proposed to require removal of the affected PT
disks. We are issuing this AD to correct the unsafe condition on these
products.
The MCAI states:

It was identified during a recent design review that power
turbine (PT) rotors with certain disks, part number (P/N) M601-
3220.6 and P/N M601-3220.7, have a reduction in the declared
theoretical PT rotor overspeed limit.
This condition, if not corrected, may lead to high energy debris
release in case of PT rotor overspeed occurrence, possibly resulting
in damage to, and/or reduced control of, the aeroplane.

You may obtain further information by examining the MCAI in the AD
docket on the internet at http://www.regulations.gov by searching for
and locating Docket No. FAA-2017-0658.

Comments

We gave the public the opportunity to participate in developing
this final rule. We considered the comment received. Cody Hargis (not
further identified) supported the NPRM.

Conclusion

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

Related Service Information

We reviewed GE Aviation Czech s.r.o. Alert Service Bulletin (ASB)
No. ASB-M601E-72-50-00-0069, ASB-M601D-72-50-00-0052, ASB-M601F-72-50-
00-0035, ASB-M601T-72-50-00-0028, and ASB-M601Z-72-50-00-0038, (single
document), dated February 21, 2017. The ASB describe procedures for
replacing the PT disk.

Costs of Compliance

We estimate that this AD affects 50 engines installed on airplanes
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
associated 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 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):