DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0781; Project Identifier AD-2021-00775-E]
RIN 2120-AA64

Airworthiness Directives; Austro Engine GmbH 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)
2021-09-04, which applies to all Austro Engine GmbH E4 and E4P model
diesel piston engines. AD 2021-09-04 requires replacing a certain oil
pump as well as the oil filter and engine oil. Since the FAA issued AD
2021-09-04, the FAA determined that the requirement to replace the oil
pump should be limited to only Austro Engine E4 and E4P model diesel
piston engines with a certain oil pump, identified by part number (P/N)
and serial number (S/N), installed. This proposed AD would require
replacing a certain oil pump, the oil filter, and the engine oil
installed on Austro Engine GmbH E4 and E4P model diesel piston 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 October 14,
2021.

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 Austro
Engine GmbH, Rudolf-Diesel-Strasse 11, 2700 Weiner Neustadt, Austria;
phone: +43 2622 23000; website: www.austroengine.at. You may view this
service information at the Airworthiness Products Section, Operational
Safety Branch, FAA, 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 at https://www.regulations.gov by
searching for and locating Docket No. FAA-2021-0781; 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, any comments
received, and other information. The street address for Docket
Operations is listed above.

FOR FURTHER INFORMATION CONTACT: Wego Wang, Aviation Safety Engineer,
ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; phone:
(781) 238-7134; fax: (781) 238-7199; email: wego.wang@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

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-2021-0781; Project Identifier
AD-2021-00775-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
the 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 we receive about this proposed AD.

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 confiden-
tial under the FOIA, and they will not be placed in the public docket of
this NPRM. Submissions containing CBI should be sent to Wego Wang, Avia-
tion 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.

Background

The FAA issued AD 2021-09-04, Amendment 39-21517 (86 FR 21637,
April 23, 2021), (AD 2021-09-04), for all Austro Engine GmbH E4 and E4P
model diesel piston engines. AD 2021-09-04 was prompted by reports of
an oil pump blockage on E4 model diesel piston engines. AD 2021-09-04
requires replacing a certain oil pump as well as the oil filter and
engine oil. The agency issued AD 2021-09-04 to prevent failure of the
engine lubrication system.

Actions Since AD 2021-09-04 Was Issued

Since the FAA issued AD 2021-09-04, the FAA determined that the
requirement to replace the oil pump should be limited to only Austro
Engine E4 and E4P model diesel piston engines with a certain oil pump
installed, identified by P/N and S/N in Austro Engine GmbH Mandatory
Service Bulletin No. MSB-E4-030/4, Revision No. 4, dated March 30,
2021.

FAA's Determination

The FAA is issuing this NPRM after determining that the unsafe
condition described previously is likely to exist or develop on other
products of the same type design.

Related Service Information Under 1 CFR Part 51

The FAA reviewed Austro Engine GmbH Mandatory Service Bulletin No.
MSB-E4-030/4, Revision No. 4, dated March 30, 2021 (the MSB). This
service information specifies procedures for replacing the affected oil
pumps installed on E4 and E4P model diesel piston engines. This service
information also specifies procedures for replacing the oil filter and
engine oil installed on these engines. In addition, this service
information identifies the applicable S/Ns of affected E4 and E4P model
diesel piston engines, the affected oil pumps requiring replacement,
and an additional oil pump replacement option. The Director of the
Federal Register previously approved the MSB for incorporation by
reference on May 10, 2021 (86 FR 21637, April 23, 2021). 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.

Proposed AD Requirements in This NPRM

This proposed AD would retain certain requirements of AD 2021-09-04.
This proposed AD would require replacement of an affected oil pump,
identified by P/N and S/N in the MSB. This proposed AD would also
require replacement of the oil filter and engine oil.

Differences Between This Proposed AD and the Service Information

The MSB specifies that the removed oil pump must be returned to
Austro Engine GmbH. The MSB specifies that information, including the
engine flight hours (FHs) recorded at the time of the oil pump
replacement, must be sent to Austro Engine GmbH. This proposed AD would
not mandate sending the removed oil pump or information, including the
engine FHs recorded at the time of oil pump replacement, to Austro
Engine GmbH.

The MSB also specifies that for all engines with 10 FHs or less, to
replace the affected oil pump, oil filter, and engine oil before the
next flight. Whereas, this proposed AD would require, for Group 1 and
Group 2 engines with 10 FHs or less, replacement of a certain oil pump,
oil filter, and engine oil within 30 days, before accumulating 10 FHs,
or during the next scheduled maintenance, whichever occurs first after
the effective date of this proposed AD.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would
affect 55 engines installed on airplanes of U.S. registry.

The FAA estimates the following costs to comply with this proposed
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
proposed AD may be covered under warranty, thereby reducing the cost
impact on affected individuals.

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

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 that the 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
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 2021-09-04, Amendment 39-21517 (86
FR 21637, April 23, 2021); and

b. Adding the following new airworthiness directive: