DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2021-0499; Project Identifier MCAI-2021-00571-E;
Amendment 39-21612; AD 2021-13-07]
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: Final rule; request for comments.
SUMMARY: The FAA is adopting a new airworthiness directive (AD)
GE Aviation Czech s.r.o. (GEAC) M601D-11, M601E-11, M601E-11A, M601E-
11AS, M601E-11S, and M601F model turboprop engines. This AD was
prompted by the manufacturer finding errors in the Airworthiness
Limitation Section (ALS) of the Engine Maintenance Manual (EMM),
including errors in the formula to determine the equivalent flight
cycles (FCs) of critical parts and errors with certain part numbers (P/
Ns). The manufacturer also determined that the life limit of a certain
compressor case is not listed in the ALS section of the applicable EMM.
This AD requires recalculating the life of critical parts and,
depending on the results of the recalculation, replacement of these
critical parts. This AD also requires replacement of a certain
compressor case. The FAA is issuing this AD to address the unsafe
condition on these products.
DATES: This AD is effective June 30, 2021.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of June 30,
The FAA must receive comments on this AD by July 30, 2021.
ADDRESSES: You may send comments, using the procedures found in
11.43 and 11.45, by any of the following methods:
Federal eRulemaking Portal: Go to https://www.regulations.gov. Follow
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 final rule, contact GE
Aviation Czech s.r.o., Beranovych 65, 199 00 Praha 18, Letnany,
Czech Republic; phone: +420 222 538 111; fax: +420 222 538 222. 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 (781) 238-7759. It is also available at https://www.regulations.gov
by searching for and locating Docket No. FAA-2021-0499.
Examining the AD Docket
You may examine the AD docket at https://www.regulations.gov by
searching for and locating Docket No. FAA-2021-0499; 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 final rule, any
comments received, and other information. The street address for the
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; fax: (781) 238-7199; email:
The European Union Aviation Safety Agency (EASA), which is the
Technical Agent for the Member States of the European Community, has
issued EASA Emergency AD 2021-0125-E, dated May 7, 2021 (referred to
after this as ``the MCAI''), to address an unsafe condition for the
specified products. The MCAI states:
Errors have been identified in the ALS section of the EMM
[Engine Maintenance Manual], including errors in the formula to
determine the equivalent flight cycles of critical parts, and
certain part numbers. It was also determined that, inadvertently,
certain M601E engines have a compressor case P/N M601-154.61
installed, the life limit of which is not listed in the ALS section
of the applicable EMM.
These conditions, if not corrected, may lead to operation of an
engine beyond the life limit of one or more critical parts, possibly
resulting in failure of the engine and consequent reduced control of
To address this potential unsafe conditions, GEAC issued [GEAC
Alert Service Bulletin (ASB) ASB-M601D-72-00-00-0075, ASB-M601E-72-
00-00-0106, ASB-M601F-72-00-00-0057 and ASB-M601Z-72-00-00-0057
(issued as a single document)], providing instructions to
recalculate the consumed life of certain
critical parts, and [GEAC ASB-M601E-72-30-00-0105], providing
instructions for certain M601E engines to replace the compressor
case with an eligible part.
For the reason described above, this [EASA] AD requires
replacement of critical parts, the recalculated life of which
exceeds the applicable life limit, and replacement of the compressor
case on certain M601E engines.
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-2021-0499.
The FAA is issuing this AD because the agency has determined 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 ASB-M601F-72-00-00-0057 ,
ASB-M601E-72-00-00-0106 , ASB-M601D-72-00-00-0075 , and ASB-
M601Z-72-00-00-0057  (single document; formatted as service
bulletin identifier [revision number]), dated May 7, 2021. This ASB
specifies procedures for calculating consumed life of the critical
parts. 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 ADDRESSES.
Other Related Service Information
The FAA reviewed GE Aviation Czech ASB-M601E-72-30-00-0105 
(formatted as service bulletin identifier [revision number]), dated May
7, 2021. This ASB introduces life limits to compressor case P/N M601-
This AD requires recalculating the life of critical parts and,
depending on the results of the recalculation, replacement of critical
parts. This AD also requires replacement of compressor case, part
number M601-154.61, installed on GEAC M601E model turboprop engines.
Differences Between the AD and the Service Information
EASA Emergency AD 2021-0125-E, dated May 7, 2021, applies to GEAC
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 model turboprop engines. This AD does
not include GEAC M601D, M601D-1, M601D-2, M601D-11NZ, M601E, M601E-21,
M601FS, M601F-11, M601F-22, M601F-32, M601T, and M601Z model turboprop
engines as these engine models are not type certificated in the United
The FAA considers this AD to be an interim action. This unsafe
condition is still under investigation by the manufacturer and,
depending on the results of that investigation, the FAA may consider
further rulemaking action.
Justification for Immediate Adoption and Determination of the Effective
Section 553(b)(3)(B) of the Administrative Procedure Act (APA) (5
U.S.C. 551 et seq.) authorizes agencies to dispense with notice and
comment procedures for rules when the agency, for ``good cause,'' finds
that those procedures are ``impracticable, unnecessary, or contrary to
the public interest.'' Under this section, an agency, upon finding good
cause, may issue a final rule without providing notice and seeking
comment prior to issuance. Further, section 553(d) of the APA
authorizes agencies to make rules effective in less than thirty days,
upon a finding of good cause.
An unsafe condition exists that requires the immediate adoption of
this AD without providing an opportunity for public comments prior to
adoption. The FAA has found that the risk to the flying public
justifies foregoing notice and comment prior to adoption of this rule.
In May 2021, the FAA received a notification from the manufacturer
about their discovery of errors with the formula for calculating the
life limit of critical parts located in the ALS of the EMM. The
manufacturer also discovered that compressor case, P/N M601-154.61,
which was modified and installed in GEAC M601E model turboprop engines,
had no corresponding life limit listed in the ALS of the corresponding
EMM. As a result of discovering these errors, the manufacturer
published service information providing instructions to update the
formula used to recalculate life limits on critical parts and introduce
a life limit for compressor case P/N M601-154.61.
Critical parts exceeding their life limits can result in failure of
the engine, further resulting in uncontained release of a critical
part, damage to the engine, and damage to the airplane. The FAA
considers the failure of a critical part to be an urgent safety issue
that requires immediate action to avoid damage to the engine and
Accordingly, notice and opportunity for prior public comment are
impracticable and contrary to the public interest pursuant to 5 U.S.C.
553(b)(3)(B). In addition, the FAA finds that good cause exists
pursuant to 5 U.S.C. 553(d) for making this amendment effective in less
than 30 days, for the same reasons the FAA found good cause to forego
notice and comment.
The FAA invites you to send any written data, views, or arguments
about this final rule. Send your comments to an address listed under
ADDRESSES. Include ``Docket No. FAA-2021-0499 and Project Identifier
MCAI-2021-00571-E'' at the beginning of your comments. The most helpful
comments reference a specific portion of the final rule, 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 final rule 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 final rule.
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 AD 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 AD, 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 AD. 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.
Regulatory Flexibility Act
The requirements of the Regulatory Flexibility Act (RFA) do not
apply when an agency finds good cause pursuant to 5 U.S.C. 553 to adopt
without prior notice and comment. Because FAA has determined that it
has good cause to adopt this rule without prior notice and comment, RFA
analysis is not required.
Costs of Compliance
The FAA estimates that this AD affects 9 engines installed on
airplanes of U.S. registry.
The FAA estimates the following costs to comply with this AD:
|Recalculate life of critical
||1 work-hour x $85 per hour =
|Replace compressor case
||10 work-hours x $85 per hour
The FAA has included all known costs
in its cost estimate.
According to the manufacturer, however, some of the costs of this AD
may be covered under warranty, thereby reducing the cost impact on
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 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, and
(2) Will not affect intrastate aviation in Alaska.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
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