AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

SUMMARY: We are adopting a new airworthiness directive (AD) for General
Electric Company (GE) CF34-10E series turbofan engines. This AD was
prompted by a report of heavy wear found on the seating surface of the
center vent duct (CVD) (commonly referred to as center vent tube)
support ring and on the inside diameter of the fan drive shaft at the
mating location. This AD requires removing from service all CVD support
assemblies and any fan drive shaft on the affected engines if wear is
found on either the CVD support ring or the fan drive shaft. We are
issuing this AD to prevent fan drive shaft failure, leading to
uncontained engine failure and damage to the airplane.

DATES: This AD is effective February 27, 2012.

ADDRESSES: For service information identified in this AD, contact GE-
Aviation, M/D Rm. 285, One Neumann Way, Cincinnati, OH 45215, phone:
(513) 552-3272; email: geae.aoc@ge.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: John Frost, Aerospace Engineer, Engine
Certification Office, FAA, 12 New England Executive Park, Burlington,
MA 01803; phone: (781) 238-7756; fax: (781) 238-7199; email:
john.frost@faa.gov.

SUPPLEMENTARY INFORMATION:

Discussion

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR
part 39 to include an AD that would apply to the specified products.
That NPRM published in the Federal
Register on October 18, 2011 (76 FR 64287). That NPRM proposed to
require removing from service all CVD support assemblies and any fan
drive shaft on the affected engines if wear is found on either the CVD
support ring or the inside diameter of the fan drive shaft.

Comments

We gave the public the opportunity to participate in developing
this AD. The following presents the comments received on the proposal
and the FAA's response to each comment.

Request To Include an Engine Serial Number (S/N)

One commenter, Embraer Aircraft Maintenance Services, requests that
we include engine S/N 994187 in the applicability. They cite the GE All
Operators Wire they received as being accurate with the affected engine
S/Ns, which includes S/N 994187.
We agree. We added S/N 994187.

Request To Allow Previous Credit

One commenter, GE, requests that we allow previous credit for
engines with records of prior CVD support assembly replacement and fan
drive shaft inspection per the Engine Manual, before the effective date
of the AD.
We agree that previous credit should be allowed. Paragraph (e) of
the AD requires compliance before accumulating 11,500 total cycles-in-
service on the engine, unless already done. We did not change the AD.

Conclusion

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

Costs of Compliance

We estimate that this AD will affect 71 GE CF34-10E series turbofan
engines installed on airplanes of U.S. registry. We also estimate that
it will take about 8 work-hours per engine to perform a replacement of
the CVD support assembly and visual inspections, and that the average
labor rate is $85 per work-hour. A replacement CVD support assembly
costs about $3,080. We estimate that two fan drive shafts will fail
inspection and require replacement. A replacement fan drive shaft costs
about $126,900. We estimate that no additional labor costs would be
incurred to perform the required part replacements as the replacements
are done at time of scheduled engine shop visit. Based on these
figures, we estimate the total cost of the AD to U.S. operators to be
$520,760.

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

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 adding the following new airworthiness
directive (AD):