DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2024-0456; Project Identifier MCAI-2024-00084-E;
Amendment 39-22691; AD 2024-05-01]
RIN 2120-AA64

Airworthiness Directives; Austro Engine GmbH Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule; request for comments.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for
certain Austro Engine GmbH Model E4 and E4P engines. This AD was
prompted by reports of engine failures and the determination that
certain batches of cap screws, installed on the inner main bearing
positions of the engine, were manufactured at the lower end of the
material strength tolerance. This AD requires replacing certain cap
screws with a part eligible for installation and prohibits installing
certain cap screws on any inner main bearing position of any engine.
This AD also prohibits installing certain engine cores on any engine
unless certain requirements are met. The FAA is issuing this AD to
address the unsafe condition on these products.

DATES: This AD is effective March 11, 2024.
The Director of the Federal Register approved the incorporation by
reference of certain publications listed in this AD as of March 11,
2024.
The FAA must receive comments on this AD by April 19, 2024.

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 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.
AD Docket: You may examine the AD docket at regulations.gov under
Docket No. FAA-2024-0456; 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, the mandatory continuing airworthiness
information (MCAI), any comments received, and other information. The
street address for Docket Operations is listed above.
Material Incorporated by Reference:
For service information identified in this final rule,
contact Austro Engine GmbH, Rudolf-Diesel-Strasse 11, A-2700 Weiner
Neustadt, Austria; phone: +43 2622 23000; website: austroengine.at.
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 (817) 222-5110. It is
also available at regulations.gov under Docket No. FAA-2024-0456.

FOR FURTHER INFORMATION CONTACT: Barbara Caufield, Aviation Safety
Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590;
phone: (781) 238-7146; email: barbara.caufield@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

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-2024-0456; Project Identifier MCAI-
2024-00084-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
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, FAA, 1600 Stewart Avenue, Suite
410, Westbury, NY 11590. Any commentary that the FAA receives which is
not specifically designated as CBI will be placed in the public docket
for this rulemaking.

Background

The European Union Aviation Safety Agency (EASA), which is the
Technical Agent for the Member States of the European Union, has issued
EASA AD 2024-0037R1, dated February 6, 2024 (EASA AD 2024-0037R1) (also
referred to as the MCAI), to address an unsafe condition on Austro
Engine GmbH Model E4 and E4P engines. The MCAI states that there were
reports of engine failures, and subsequent investigation identified a
cap screw installed on an inner main bearing that had failed, which
caused the engine failure. Further investigation determined that
certain batches of cap screws meeting the lower end of their design
specification could fail when installed on the inner main bearing and
the engine is operated in specific operating conditions. To
address this unsafe condition, the manufacturer published a service
bulletin to provide instructions for replacement of these affected
parts. EASA then issued EASA Emergency AD 2024-0037-E, dated February
2, 2024 (EASA Emergency AD 2024-0037-E), which specified replacing the
cap screws installed on the inner main bearing positions with
serviceable parts and additional requirements for installation of
certain parts and engines.
Additionally, the manufacturer has determined that certain batches
of cap screws, installed on the inner main bearing positions of the
engine, were produced at the lower end of the material strength
tolerance for Class 8.8 screws. Depending on the magnitude of the cap
screw's strength properties, the potential for failure, leading to
engine failure, exists in cases where abnormal operating conditions are
experienced such as fuel quality issues or significant deviations from
the fuel system requirements.
Since EASA Emergency AD 2024-0037-E was issued, due to requests for
clarification, the compliance time for certain engines has been
modified. As a result, EASA revised EASA Emergency AD 2024-0037-E and
issued EASA AD 2024-0037R1 to include the updated compliance times and
additionally to include ferry flight criteria for certain affected
engines. The unsafe condition, if not addressed, could result in engine
failure, reduced control of the airplane, and for single engine
airplanes, an emergency landing, possibly resulting in damage to the
airplane and injury to occupants.
You may examine the MCAI in the AD docket at regulations.gov under
Docket No. FAA-2024-0456.

Related Service Information Under 1 CFR Part 51

The FAA reviewed the following service information:
Austro Engine GmbH Mandatory No. Service Bulletin MSB-E4-
042, Revision 0, dated January 31, 2024, which details certain engines
and engine cores with affected cap screws installed on the inner main
bearing positions of the engine.
Austro Engine GmbH Work Instruction WI-MSB-E4-042,
Revision 0, dated February 2, 2024, which specifies instructions for
replacing the affected cap screws installed on the inner main bearing
positions of the engine.
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.

FAA's Determination

These products have been approved by the aviation authority of
another country and are approved for operation in the United States.
Pursuant to the FAA's bilateral agreement with this State of Design
Authority, it has notified the FAA of the unsafe condition described in
the MCAI and service information referenced above. The FAA is issuing
this AD after determining that the unsafe condition described
previously is likely to exist or develop on other products of the same
type design.

AD Requirements

This AD requires replacing certain cap screws, installed on the
inner main bearing positions of the engine, with a part eligible for
installation. This AD also prohibits installing certain cap screws on
any inner main bearing position of any engine. This AD also prohibits
installing certain engine cores on any engine unless certain
requirements are met.

Justification for Immediate Adoption and Determination of the Effective
Date

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 forgoing notice and comment prior to adoption of this rule
because the cap screws installed on the inner main bearing positions of
the engine are critical components for engine operation. The inadequate
strength properties and subsequent failure of the cap screws could lead
to engine failure during flight. The FAA also has received no
information indicating how quickly the condition may propagate to
failure, therefore these affected parts must be replaced before further
flight on certain engines. Consequently, the required replacement of
cap screws before those engines is shorter than the time necessary for
the public to comment and for publication of the final rule.
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 forgo notice and
comment.

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
a rule without prior notice and comment. Because the 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 357 engines installed on
airplanes of U.S. registry.
The FAA estimates the following costs to comply with this AD.

Estimated Costs

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
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.

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 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
reference, Safety.

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: