AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

SUMMARY: We are revising an existing airworthiness directive (AD) for
Thielert Aircraft Engines GmbH models TAE 125-02-99 and TAE 125-01
reciprocating engines. That AD currently requires replacing the
existing rail pressure control valve with an improved rail pressure
control valve. This new AD requires the same actions but relaxes the
initial compliance time from within 100 flight hours to within 600
flight hours for TAE 125-01 reciprocating engines. This AD was prompted
by the determination that our AD was inadvertently more restrictive
than European Aviation Safety Agency AD 2008-0128. We are issuing this
AD to prevent engine in-flight shutdown, possibly resulting in reduced
control of the aircraft.

DATES: This AD is effective February 3, 2012.

ADDRESSES: For service information identified in this AD, contact
Thielert Aircraft Engines GmbH, Platanenstrasse 14 D-09350,
Lichtenstein, Germany; phone: +49-37204-696-0; fax: +49-37204-696-55;
email: engines.com">info@centurion-engines.com. You may review copies of the
referenced service information at the FAA, 12 New England Executive
Park, Burlington, MA. For information on the availability of this
material at the FAA, call (781) 238-7125.

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.gov;
or in person at the Docket Management Facility
between 9 a.m. and 5 p.m., Monday through Friday, except Federal
holidays. The AD docket contains this AD, the regulatory evaluation,
any comments received, and other information. The address for the
Docket Office (phone: (800) 647-5527) is Document Management Facility,
U.S. Department of Transportation, Docket Operations, M-30, West
Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE.,
Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Alan Strom, Aerospace Engineer, Engine
Certification Office, FAA, Engine & Propeller Directorate, 12 New
England Executive Park, Burlington, MA 01803; phone: (781) 238-7143;
fax: (781) 238-7199; email: alan.strom@faa.gov.

SUPPLEMENTARY INFORMATION:

Discussion

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR
part 39 to revise AD 2010-06-12, Amendment 39-16236 (75 FR 12439, March
16, 2010). That AD applies to the specified products. The NPRM
published in the Federal Register on October 18, 2011 (76 FR 64285).
That NPRM proposed to require relaxing the initial compliance time from
within 100 flight hours to within 600 flight hours for TAE 125-01
reciprocating engines.

Comments

We gave the public the opportunity to participate in developing
this AD. We received no comments on the NPRM.

Clarification of the VRail Plug Modification

Since we issued the NPRM, we determined that the compliance
paragraph describing the Vrail plug modification needed clarification.
We changed paragraph (e)(1)(i) in the AD to describe what existing
parts need to be removed and what part number needs to be installed.

Conclusion

We reviewed the relevant data and determined that air safety and
the public interest require adopting the AD with the change described
previously.

Costs of Compliance

Based on the service information, we estimate that this AD will
affect about 370 TAE 125-01 and TAE 125-02-99 reciprocating engines
installed on products of U.S. registry. We also estimate that it will
take about 1.5 work-hours per engine to comply with this AD. The
average labor rate is $85 per work-hour. Required parts will cost about
$500 per engine. Based on these figures, we estimate the cost of the AD
for initial replacement on U.S. operators to be $232,175.

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.
We are 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

We have determined that 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,
(2) Is not a ``significant rule'' under DOT Regulatory Policies and
Procedures (44 FR 11034, February 26, 1979),
(3) Will not affect intrastate aviation in Alaska, and
(4) 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.

Adoption of 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 removing airworthiness directive (AD)
2010-06-12, Amendment 39-16236, (75 FR 12439, March 16, 2010), and
adding the following new AD: