DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2019-1021; Project Identifier MCAI-2019-00120-E]
RIN 2120-AA64

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

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to supersede airworthiness directive (AD)
2016-07-13 and AD 2018-03-22 which apply to certain GE Aviation Czech
s.r.o. M601D-11, M601E-11, M601E-11A, M601E-11AS, M601E-11S, and M601F
turboprop engines. AD 2016-07-13 requires inspection of the engine
power turbine (PT) disk and, if found damaged, its replacement with a
part eligible for installation. AD 2018-03-22 requires the removal of
certain engine PT disks identified by part number (P/N) installed on
the affected engines. Since the FAA issued AD 2016-07-13 and AD 2018-
03-22, the manufacturer identified additional P/Ns and serial numbers
(S/Ns) of engine PT disks affected by damage or non-conformity. This
proposed AD would require an inspection of the engine PT disk and, if
found damaged, its replacement with a part eligible for installation.
This proposed AD would also require the removal of certain engine PT
disks identified by P/N installed on the affected engines. The FAA is
proposing this AD to address the unsafe condition on these products.

DATES: The FAA must receive comments on this proposed AD by April 6,
2020.

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 https://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 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; email: tp.ops@ge.com. 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 https://www.regulations.
gov by searching for and locating Docket No. FAA-2019-1021;
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 mandatory continuing airworthiness information (MCAI),
the regulatory evaluation, any comments received, and other
information. The street address for Docket Operations is listed above.
Comments will be available in the AD docket shortly after receipt.

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:

Comments Invited

The FAA invites you to send any written relevant data, views, or
arguments about this proposed AD. Send your comments to an address
listed under the ADDRESSES section. Include "Docket No. FAA-2019-1021;
Project Identifier MCAI-2019-00120-E" at the beginning of your
comments. The FAA specifically invites comments on the overall
regulatory, economic, environmental, and energy aspects of this NPRM.
The FAA will consider all comments received by the closing date and may
amend this NPRM because of those comments.

Except for Confidential Business Information as described in the
following paragraph, and other information as described in 14 CFR
11.35, the FAA will post all comments received, without change, to
https://www.regulations.gov, including any personal information you
provide. The FAA will also post a report summarizing each substantive
verbal contact received about this NPRM.

Confidential Business Information

Confidential Business Information (CBI) is commercial or financial
information that is both customarily and actually treated as private by
its owner. Under the Freedom of Information Act (FOIA) (5 U.S.C. 552),
CBI is exempt from public disclosure. If your comments responsive to
this NPRM contain commercial or financial information that is
customarily treated as private, that you actually treat as private, and
that is relevant or responsive to this NPRM, it is important that you
clearly designate the submitted comments as CBI. Please mark each page
of your submission containing CBI as "PROPIN." The FAA will treat
such marked submissions as confidential under the FOIA, and they will
not be placed in the public docket of this NPRM. Submissions containing
CBI should be sent to Mehdi Lamnyi, Aerospace Engineer, ECO Branch,
FAA, 1200 District Avenue, Burlington, MA 01803. Any commentary that
the FAA receives which is not specifically designated as CBI will be
placed in the public docket for this rulemaking.

Discussion

The FAA issued AD 2016-07-13, Amendment 39-18458 (81 FR 20222,
April 7, 2016), ("AD 2016-07-13"), and AD 2018-03-22, Amendment 39-
19195 (83 FR 6455, February 14, 2018), ("AD 2018-03-22") for certain
GE Aviation Czech s.r.o. M601D-11, M601E-11, M601E-11A, M601E-11AS,
M601E-11S, and M601F turboprop engines. AD 2016-07-13 requires
inspection of the engine PT disk and, if found damaged, its replacement
with a part eligible for installation. AD 2016-07-13 resulted from the
discovery of damage to certain engine PT disks during engine shop
visits. AD 2018-03-22 requires the removal of certain engine PT disks
installed on the affected engines. AD 2018-03-22 resulted from a design
review by the manufacturer that determined engine PT rotors with
certain engine PT disks have less overspeed margin than originally
stated during product certification.

The FAA issued AD 2016-07-13 to prevent failure of the engine PT
disk, which could result in release of high-energy debris, damage to
the engine, and reduced control of the airplane. The FAA issued AD
2018-03-22 to prevent failure of the engine PT rotor, which could result
in uncontained release of the engine PT disk, damage to the engine, and
damage to the airplane.

Actions Since AD 2016-07-13 and 2018-03-22 Were Issued

Since the FAA issued AD 2016-07-13 and AD 2018-03-22, The European
Union Aviation Safety Agency (EASA), which is the Technical Agent for
the Member States of the European Community, has issued EASA AD 2019-
0143, dated June 13, 2019 (referred to after this as "the MCAI"), to
address the unsafe condition on these products. The MCAI states:

During engine shop visits or overhauls, certain PT discs may
have been damaged in the area of the balance weights. Additional PT
discs with non-conforming geometry of the slot radius may also have
been released to service as a result of incorrect machining of the
PT disc slot.

This condition, if not detected and corrected, could lead to PT
disc failure, with subsequent release of high-energy debris,
possibly resulting in damage to, and/or reduced control of, the
aeroplane. To address this potential unsafe condition, GEAC
published a Service Bulletin (SB) to provide instructions to inspect
and, depending on findings, replace certain PT discs, and EASA
issued AD 2016-0025-E accordingly.

After that AD was issued, it was identified that PT rotors with
certain P/N discs have a reduction in the declared theoretical PT
rotor overspeed limit. Consequently, GEAC issued a new ASB,
providing PT disc replacement instructions, and EASA issued AD 2017-
0100, to require replacement of the affected PT discs, and to
prohibit their further installation.

After those ADs were issued, GEAC identified additional P/N and
s/n of PT discs affected by damage or non-conformity. For those, as
well as for the PT discs affected by the reduction of the declared
theoretical PT rotor overspeed limit, an update of the risk
assessment was performed, and GEAC issued the original issue of the
ASB, later revised, providing applicable instructions.

Consequently, EASA issued AD 2019-0061, retaining the
requirements of EASA AD 2016-0025-E and EASA AD 2017-0100, which
were superseded, and requiring a one-time inspection and, depending
on findings, replacement of certain PT discs identified by P/N and
s/n. That [EASA] AD also required replacement of certain PT discs
identified by P/N, and prohibited (re)installation of affected
parts.

Since that [EASA] AD was issued, it has been determined that the
compliance time for replacement of affected part on Group 2 engines
has to be amended, and GEAC published the ASB (now at Revision 02).

For the reason stated above, this [EASA] AD retains the
requirements of EASA AD 2019-0061, which is superseded, introducing
amended compliance times for Group 2 engines.

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-2019-1021.

Related Service Information Under 1 CFR Part 51

The FAA reviewed GE Aviation Czech s.r.o Alert Service Bulletin
(ASB) ASB-M601E-72-50-00-0069[02], ASB-M601D-72-50-00-0052[02], ASB-
M601T-72-50-00-0028[02], ASB-M601F-72-50-00-0035[02] and ASB-M601Z-72-
50-00-0038[02] (single document), dated June 11, 2019. The ASB provides
procedures for replacing the engine PT disk. 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

This product has been approved by EASA, and is approved for
operation in the United States. Pursuant to our bilateral agreement
with the European Community, EASA has notified us of the unsafe
condition described in the MCAI and service information referenced
above. The FAA is proposing this AD because it evaluated all the
relevant information provided by EASA 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 would retain certain requirements of AD 2016-07-13
and AD 2018-03-22. This proposed AD would require an inspection of the
engine PT disk and, if found damaged, its replacement with a part
eligible for installation. This proposed AD would also require the
removal of certain engine PT disks identified by P/N installed on the
affected engines. In addition, this proposed AD expands the
applicability to additional engine PT disk P/Ns and S/Ns affected by
the damage or non-conformity.

Differences Between This Proposed AD and the MCAI

EASA AD 2019-0143, dated June 13, 2019, identifies the
applicability as GE Aviation Czech s.r.o. M601D, M601D-1, M601D-2,
M601D-11, M601D-11NZ, M601E, M601E-11, M601E-11A, M601E-11AS, M601E-
11S, M601E-21, M601F, M601FS, M601F-11, M601F-22, M601F-32, M601T, and
M601Z turboprop engines. This proposed AD is applicable to only GE
Aviation Czech s.r.o. M601D-11, M601E-11, M601E-11A, M601E-11AS, M601E-
11S, and M601F turboprop engines. The GE Aviation Czech s.r.o.
turboprop engines not listed in this proposed AD have not been type
validated for operation in the United States.

Costs of Compliance

The FAA estimates that this proposed AD affects 24 GE Aviation
Czech s.r.o. M601 turboprop engines installed on airplanes of U.S.
registry. The FAA estimates that 12 affected turboprop engines are
"Group 1" engines and 12 are "Group 2" engines.

The FAA estimates the following costs to comply with this proposed AD:

Estimated Costs

The FAA estimates the following costs to do any necessary
replacements that would be required based on the results of the
proposed inspection. The FAA has no way of determining the number of
engines that might need this replacement:

On-Condition Costs

According to the manufacturer, some of the costs of this proposed
AD may be covered under warranty, thereby reducing the cost impact on
affected individuals. The FAA does not control warranty coverage for
affected individuals. As a result, the FAA has included all costs in
its cost estimate.

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 engines, propellers, and
associated appliances to the Manager, Engine and Propeller Standards
Branch, Policy and Innovation Division.

Regulatory Findings

The FAA 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) Will not affect intrastate aviation in Alaska, and

(3) 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:

a. Removing airworthiness directive (AD) 2016-07-13, Amendment 39-18458
(81 FR 20222, April 7, 2016), and AD 2018-03-22, Amendment 39-19195 (83
FR 6455, February 14, 2018), and

b. Adding the following new AD: