AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

SUMMARY: We are revising an existing airworthiness directive (AD) for
the products listed above. This AD was prompted by Turbomeca restoring
all or part of the life limits of the affected discs, and European
Aviation Safety Agency's (EASA) issuance of AD 2010-0101R2, dated March
24, 2011, to do the same. Turbomeca has introduced a reinforced eddy-
current inspection (ECI) which, combined with a revised analysis,
allows the life limit of the affected discs to be extended. We are
issuing this revision to prevent failure of the gas generator (GG)
second stage turbine disc which could result in the release of high
energy debris and damage to the helicopter.

DATES: This AD is effective January 17, 2012.

ADDRESSES: For service information identified in this AD, contact
Turbomeca, 40220 Tarnos, France; phone: 33 05 59 74 40 00; fax: 33 05
59 74 45 15; email: noria-dallas@turbomeca.com. You may review copies
of the referenced service information at the FAA, Engine & Propeller
Directorate, 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: Frederick Zink, Aerospace Engineer,
Engine Certification Office, FAA, 12 New England Executive Park,
Burlington, MA; phone: (781) 238-7779; fax: (781) 238-7199; email:
frederick.zink@faa.gov.

SUPPLEMENTARY INFORMATION:

Discussion

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR
part 39 to revise AD 2010-19-06, amendment 39-16434 (75 FR 57371,
September 21, 2010). That AD applies to the specified products. The
NPRM published in the Federal Register on July 19, 2011 (76 FR 42610).
That NPRM proposed to require removing GG second stage turbine discs,
P/N 0 292 25 040 0, that do not have the ``CFR'' marking, from service
before exceeding 4,000 cycles-in-service (CIS) since-new. That NPRM
also proposed to require removing GG second stage turbine discs, P/N 0
292 25 040 0, that have the ``CFR'' marking, from service before
exceeding 6,500 CIS since-new.
That NPRM was prompted by Turbomeca restoring all or part of the
life limits of the affected discs, per
EASA's issuance of AD 2010-0101R2, dated March 24, 2011, to do the
same. Turbomeca's reinforced ECI provides a lower (improved) detection
threshold for metallurgical non-conformities. This reinforced ECI,
combined with a revised analysis, allows the life limit of the post-
TU347 GG second stage turbine discs identified as ``CFR'' to be
extended to 6,500 CIS since-new. Further, as a result of this testing
and analysis, the non-CFR 2nd stage turbine discs pre-TU347 inspection
disc life has been extended to 4,000 CIS since-new. This new AD still
prevents disc failure but also extends the life limits of the affected
discs. We are issuing this revision to prevent failure of the GG second
stage turbine disc which could result in the release of high energy
debris and damage to the helicopter.

Comments

We gave the public the opportunity to participate in developing
this AD. We received no comments on the NPRM (76 FR 42610, July 19,
2011) or on the determination of the cost to the public.

Conclusion

We reviewed the relevant data and determined that air safety and
the public interest require adopting the AD as proposed except for
minor clarifications. We have determined that these minor changes:
Are consistent with the intent that was proposed in the
NPRM (76 FR 42610, July 19, 2011) for correcting the unsafe condition;
and
Do not add any additional burden upon the public than was
already proposed in the NPRM (76 FR 42610, July 19, 2011).

Costs of Compliance

We estimate that this AD will affect 203 Turbomeca Arriel 1 series
turboshaft engines on helicopters of U.S. registry. We estimate that no
additional labor costs will be incurred to return part of the life
limit of the discs that do not have the ``CFR'' marking to the original
published life limit. Based on these figures, we estimate the total
cost of this AD to U.S. operators to be $0.

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)
2010-19-06, Amendment 39-16434 (75 FR 57371, September 21, 2010), and
adding the following new AD: