DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2018-0259; Product Identifier 2018-NE-09-AD]
RIN 2120-AA64

Airworthiness Directives; Rolls-Royce Corporation Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to adopt a new airworthiness directive (AD) for
Rolls-Royce Corporation (RRC) AE 2100D2A and AE 2100D3 model turboprop
engines and AE 3007A2 model turbofan engines. This proposed AD was
prompted by the possibility of a low-cycle fatigue failure on certain
turbine wheels. This proposed AD would require removing the affected
turbine wheels at the next engine shop visit or before reaching the new
reduced life limit, whichever occurs first, and replacing them with
parts eligible for installation. We are proposing this AD to address
the unsafe condition on these products.

DATES: We must receive comments on this proposed AD by June 14, 2018.

ADDRESSES: You may send comments, using the procedures found in 14 CFR
11.43 and 11.45, by any of the following methods:

Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the
instructions for submitting comments.

Fax: 202-493-2251.

Mail: U.S. Department of Transportation, Docket Operations, M-30, West
Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE,
Washington, DC 20590.

Hand Delivery: Deliver to Mail address above between 9 a.m. and 5 p.m.,
Monday through Friday, except Federal holidays.

For service information identified in this NPRM, contact Rolls-
Royce Corporation, 450 South Meridian Street, Indianapolis, IN 46225;
phone: 317-230-3774. You may view this service information at the FAA,
Engine and Propeller Standards Branch, 1200 District Avenue,
Burlington, MA 01803. 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-2018-0259;
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 NPRM, the regulatory evaluation, any comments received, and other
information. The street address for Docket Operations (phone: 800-647-
5527) is listed above. Comments will be available in the AD docket
shortly after receipt.

FOR FURTHER INFORMATION CONTACT: Kyri Zaroyiannis, Aerospace Engineer,
Chicago ACO Branch, FAA, 2300 E Devon Ave., Des Plaines, IL 60018;
phone: 847-294-7836; fax: 847-294-7834; email:
kyri.zaroyiannis@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send any written relevant data, views, or
arguments about this proposal. Send your comments to an address listed
under the ADDRESSES section. Include "Docket No. FAA-2018-0259;
Product Identifier 2018-NE-09-AD" at the beginning of your comments.
We specifically invite comments on the overall regulatory, economic,
environmental, and energy aspects of this NPRM. We will consider all
comments received by the closing date and may amend this NPRM because
of those comments.

We will post all comments we receive, without change, to http://www.
regulations.gov, including any personal information you provide. We
will also post a report summarizing each substantive verbal contact we
receive about this NPRM.

Discussion

We were prompted to issue this NPRM based upon a report of the
discovery of steel inclusion in the production process at an RRC
forging supplier. Ultrasonic inspection at the forging supplier
revealed steel impurities could be introduced into turbine wheels
during forging. Analysis and testing by RRC of these wheels indicated
that, because of imperfections, these turbine wheels could not be
operated safely up to their published life limits. The affected turbine
wheels include 1st-stage gas generator turbine wheels, installed on AE
2100D2A and AE 2100D3 model turboprop engines, and 1st-stage high-
pressure turbine (HPT) wheels, installed on AE 3007A2 turbofan engines.

This condition, if not addressed, could result in uncontained
turbine wheel release, damage to the engine, and damage to the
airplane.

Related Service Information Under 1 CFR Part 51

We reviewed RRC Alert Service Bulletin (ASB) AE 2100D2-A-72-090,
Revision 1, dated July 11, 2014, and RRC ASB AE 2100D3-A-72-286,
Revision 1, dated July 11, 2014 (one document, referred to herein as
"RRC ASB AE 2100D2-A-72-090/AE 2100D3-A-72-286"), and RRC ASB AE
3007A-A-72-419, Revision 2, dated December 4, 2017. RRC ASB AE 2100D2-
A-72-090/AE 2100D3-A-72-286 provides removal and replacement
instructions and a new life limit for the affected 1st-stage gas
generator turbine wheels installed on RRC AE 2100D2A and AE 2100D3
model turboprop engines. ASB AE 3007A-A-72-419 provides removal and
replacement instructions and a new life limit for 1st-stage HPT wheels
installed on RRC AE 3007A2 model turbofan engines. 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.

FAA's Determination

We are proposing this AD because we evaluated all the relevant
information and determined the unsafe condition described previously is
likely to exist or develop in other products of the same type design.

Proposed AD Requirements

This proposed AD requires the removal and replacement of the
affected turbine wheels at the next engine shop visit or before
reaching their new life limit, whichever occurs first.

Costs of Compliance

We estimate that this proposed AD affects nine engines installed on
airplanes of U.S. registry.

We estimate the following costs to comply with this proposed 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.

Regulatory Findings

We determined that this proposed AD would not have federalism
implications under Executive Order 13132. This proposed AD would 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 proposed
regulation:

(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.

The Proposed Amendment

Accordingly, under the authority delegated to me by the
Administrator, the FAA proposes to amend 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):