DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
Docket No. FAA-2022-0385; Project Identifier MCAI-2021-00786-E]
Airworthiness Directives; GE Aviation Czech s.r.o. (Type
Certificate Previously Held by WALTER Engines a.s., Walter a.s., and
MOTORLET a.s.) Turboprop Engines
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD)
for certain GE Aviation Czech s.r.o. (GEAC) M601D-11, M601E-11, M601E-
11A, M601E-11AS, M601E-11S, and M601F model turboprop engines. This
proposed AD was prompted by the absence of life limits for propeller
shaft part number (P/N) M601-6081.6 in the airworthiness limitation
section of the applicable GEAC M601 Engine Shop Manual. This AD was
also prompted by a report that operators may not have been provided
with enough data to determine the accumulated life of certain propeller
shafts. For M601F model turboprop engines, this proposed AD would
require removal and replacement of the propeller shaft before the
propeller shaft accumulates 12,000 flight hours (FHs) since first
installation on an engine, or before accumulating 350 FHs after the
effective date of this AD, whichever occurs later, with a part eligible
for installation. For M601D-11, M601E-11, M601E-11A, M601E-11AS, and
M601E-11S model turboprop engines, this proposed AD would require
calculation of the accumulated life of the propeller shaft and,
depending on the number of accumulated FHs removal and replacement of
the propeller shaft with a part eligible for installation. 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 May 16, 2022.
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., Beranov[yacute]ch 65, 199 02 Praha 9,
Let[ncaron]any, Czech Republic; phone: +420 222 538 111. 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
Examining the AD Docket
You may examine the AD docket at https://www.regulations.gov by
searching for and locating Docket No. FAA-2022-0385; 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), any comments
received, and other information. The street address for Docket
Operations is listed above.
FOR FURTHER INFORMATION CONTACT: Barbara Caufield, Aviation Safety
Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803;
phone: (781) 238-7146; email: firstname.lastname@example.org.
The FAA invites you to send any written relevant data, views, or
arguments about this proposal. Send your comments to an address listed
under ADDRESSES. Include "Docket No. FAA-2022-0385; Project Identifier
MCAI-2021-00786-E" at the beginning of your comments. The most helpful
comments reference a specific portion of the proposal, explain the
reason for any recommended change, and include supporting data. The FAA
will consider all comments received by the closing date and may amend
this proposal because of those comments.
Except for Confidential Business Information (CBI) 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 agency will also post a report summarizing each
substantive verbal contact received about this NPRM.
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
Barbara Caufield, Aviation Safety 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.
The European Union Aviation Safety Agency (EASA), which is the
Technical Agent for the Member States of the European Union, has issued
EASA AD 2021-0154, dated July 1, 2021 (referred to after this as "the
MCAI"), to address the unsafe condition on these products. The MCAI states:
It has been determined that the life limit for the propeller
shaft P/N M601-6081.6 is not published in the applicable ALS for
M601 engines. In addition, it has also been reported that some data,
which can be used to determine the accumulated life of certain
propeller shafts, may have not been provided to operators, so the
propeller shaft life limit may not have been implemented correctly.
These conditions, if not corrected, may lead to failure of a
propeller shaft, possibly resulting in detachment of the propeller
and consequent damage to the engine and/or the aircraft, and reduced
control of the aeroplane.
To address this potential unsafe condition, GEAC issued the
original issue of the ASB, providing applicable instructions, and
EASA issued AD 2021-0052 to require implementation of the applicable
life limit and replacing each propeller shaft with a serviceable
Since that [EASA] AD was issued, additional data, which can be
used to determine the accumulated life of certain propeller shafts,
and to support an extended compliance time for Group 1 engines, has
been made available; GEAC revised accordingly the ASB (now at
For the reasons described above, this [EASA] AD partially
retains the requirements of EASA AD 2021-0052, which is superseded,
introducing updated affected population and different compliance
You may obtain further information by examining the MCAI in the AD
docket at https://www.regulations.gov by searching for and locating
Docket No. FAA-2022-0385.
This product has been approved by the aviation authority of another
country, and is approved for operation in the United States. Pursuant
to the FAA's bilateral agreement with the State of Design Authority,
the FAA has been notified of the unsafe condition described in the EASA
AD. The FAA is issuing this AD after determining that the unsafe
condition described previously is likely to exist or develop
in other products of the same type design.
Related Service Information Under 1 CFR Part 51
The FAA reviewed GE Aviation Czech Alert Service Bulletin (ASB)
ASB-M601F-72-10-00-0056 , ASB-M601D-72-10-00-0072 , ASB-M601E-
72-10-00-0103 , and ASB-M601Z-72-10-00-0056  (single document;
formatted as service bulletin identifier [revision number]), dated May
31, 2021. This ASB specifies procedures for calculating the accumulated
life of certain propeller shafts. This ASB also specifies procedures
for replacing certain propeller shafts. 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
Proposed AD Requirements in This NPRM
For M601F model turboprop engines, this proposed AD would require
removal and replacement of the propeller shaft with a part eligible for
installation before the propeller shaft accumulates 12,000 FHs since
first installation on an engine, or before accumulating 350 FHs after
the effective date of this AD, whichever occurs later. For M601D-11,
M601E-11, M601E-11A, M601E-11AS, and M601E-11S model turboprop engines,
this proposed AD would require calculation of the accumulated life of
the propeller shaft and, depending on the number of accumulated FHs,
removal and replacement of the propeller shaft with a part eligible for
Differences Between This Proposed AD and the MCAI
EASA AD 2021-0154, dated July 1, 2021, applies to M601D, M601D-1,
M601D-2, M601D-11, M601D-11NZ, M601E, M601E-11, M601E-11A, M601E-11AS,
M601E-11S, M601E-21, M601F, M601F-11, M601F-22, M601F-32, M601FS,
M601T, and M601Z model turboprop engines. This AD does not include
M601D, M601D-1, M601D-2, M601D-11NZ, M601E, M601E-21, M601F-11, M601F-
22, M601F-32, M601FS, M601T, and M601Z model turboprop engines as these
engine models are not type certificated in the United States.
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would
affect 14 engines installed on airplanes of U.S. registry. The FAA
estimates that 7 M601D-11, and 7 M601E-11 model turboprop engines
installed on airplanes of U.S. registry would require calculation of
the time since new (TSN) of the propeller shaft and removal and
replacement of the propeller shaft. The FAA estimates that zero M601E-
11A, M601E-11AS, M601E-11S, and M601F model turboprop engines installed
on airplanes of U.S. registry would require replacement of the
The FAA estimates the following costs to comply with this proposed AD:
COST PER PRODUCT
COST ON U.S. OPERATORS
|Calculate the total TSN of the propeller shaft.
|| 1 work-hour x $85 per hour = $85.
|Remove and replace the propeller shaft
|| 105 work-hours x $85 per hour = $8,925.
The FAA has included all known costs in its cost estimate.
According to the manufacturer, however, some of the costs of this
proposed AD may be covered under warranty, thereby reducing the cost
impact on affected operators.
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.
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) 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
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