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[Federal Register Volume 76, Number 201 (Tuesday, October 18, 2011)]
[Proposed Rules]
[Pages 64287-64289]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-26824]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2011-0599; Directorate Identifier 2011-NE-19-AD]
RIN 2120-AA64

Airworthiness Directives; General Electric Company CF34-10E 
Series Turbofan Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to adopt a new airworthiness directive (AD) for 
General Electric Company (GE) CF34-10E series turbofan engines. This 
proposed AD was

[[Page 64288]]

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 proposed AD would require removing from service 
CVD support assemblies from certain serial numbers (S/Ns) of CF34-10E 
series turbofan engines. This proposed AD would also require removing 
any fan drive shaft from service if wear is found on either the CVD 
support ring or the fan drive shaft. We are proposing this AD to 
prevent fan drive shaft failure, leading to uncontained engine failure 
and damage to the airplane.

DATES: We must receive comments on this proposed AD by December 2, 
2011.

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 http://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 AD, contact GE-Aviation, 
M/D Rm. 285, One Neumann Way, Cincinnati, OH 45215, phone: 513-552-
3272; e-mail: geae.aoc@ge.com. 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 proposed AD, the regulatory 
evaluation, any comments received, and other information. The street 
address for the Docket Office (phone: 800-647-5527) is in the ADDRESSES 
section. Comments will be available in the AD docket shortly after 
receipt.

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; e-mail: 
john.frost@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to send any written relevant data, views, or 
arguments about this proposal. Send your comments to an address listed 
under the ADDRESSES section. Include ``Docket No. FAA-2011-0599; 
Directorate Identifier 2011-NE-19-AD'' at the beginning of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of this proposed AD. We 
will consider all comments received by the closing date and may amend 
this proposed AD because of those comments.
    We will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We 
will also post a report summarizing each substantive verbal contact we 
receive about this proposed AD.

Discussion

    We received a report of wear found on the seating surface of the 
CVD support ring and on the inside diameter of the fan drive shaft, 
where the two parts are in contact with each other. The wear was caused 
by relative motion between the CVD support assembly and the fan drive 
shaft during engine operation. The relative motion resulted from CVD 
support assemblies with improper sleeve thread lengths. This 
nonconformance was caused during manufacture, and the affected parts 
were released into service. A subpopulation of engines has been 
identified by engine S/N, that could have the same quality escape. Once 
removed, the CVD support assembly (consisting of self-locking nut, part 
number (P/N) 2226M57G03, threaded sleeve, P/N 2226M55P03, and support 
ring, P/N 2226M56P01) will be inspected for evidence of wear, and then 
never used again. This condition, if not corrected, could result in 
low-cycle-fatigue failure of the fan drive shaft, leading to engine 
failure.

FAA's Determination

    We are proposing this AD because we evaluated all the relevant 
information and determined the condition described previously is unsafe 
and is likely to exist or develop in other products of the same type 
design.

Proposed AD Requirements

    This proposed AD would require:
     First inspecting the seating surface of the CVD support 
ring for wear, and then inspecting the fan drive shaft inside diameter 
for wear, where the two parts come in contact with each other;
     If wear is found on either the CVD support ring seating 
surface or the corresponding contact area inside the fan drive shaft, 
then removing the fan drive shaft from service; and
     Removing from service all of the CVD support assemblies 
from the affected S/N engines identified in the proposed AD.

Costs of Compliance

    We estimate that this proposed AD would affect 71 GE CF34-10E 
series turbofan engines installed on airplanes of U.S. registry. We 
also estimate that it would 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 would 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

    We 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

[[Page 64289]]

distribution of power and responsibilities among the various levels of 
government.
    For the reasons discussed above, I certify this proposed 
regulation:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Is not a ``significant rule'' under the 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.

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 adding the following new 
airworthiness directive (AD):

General Electric Company: Docket No. FAA-2011-0599; Directorate 
Identifier 2011-NE-19-AD.

(a) Comments Due Date

    We must receive comments by December 2, 2011.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to General Electric Company (GE) CF34-10E series 
turbofan engines, serial number (S/N) 994116, and S/Ns 994118 
through 994186 inclusive.

(d) Unsafe Condition

    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. The wear is caused by 
relative motion between the CVD support assembly (consisting of 
self-locking nut, part number (P/N) 2226M57G03, threaded sleeve, P/N 
2226M55P03, and support ring, P/N 2226M56P01) and the fan drive 
shaft, during engine operation. We are issuing this AD to prevent 
fan drive shaft failure, leading to uncontained engine failure and 
damage to the airplane.

(e) Compliance

    Comply with this AD before accumulating 11,500 total cycles-in-
service on the engine, unless already done.

(f) Inspection and Removal From Service of CVD Support Assembly; and 
Determination of Fan Drive Shaft Serviceability

    Visually inspect the seating surface of the CVD support ring for 
wear.
    (1) If there is sign of wear on the CVD support ring, remove the 
CVD support assembly and the fan drive shaft from service before 
further flight.
    (2) If there is no sign of wear on the CVD support ring, remove 
the CVD support assembly from service and borescope inspect the 
inside diameter of the fan drive shaft at the CVD support ring 
contact area, for wear.
    (3) If there is sign of wear on the fan drive shaft, remove the 
fan drive shaft from service before further flight.

(g) Installation Prohibition

    After the effective date of this AD, do not return to service 
any CVD support assembly (consisting of self-locking nut, P/N 
2226M57G03, threaded sleeve, P/N 2226M55P03, and support ring, P/N 
2226M56P01) removed from service as specified in this AD.

(h) Definition

    For the purposes of this AD, the phrase ``any sign of wear'' is 
defined as any visual indication of removal of parent material from 
the CVD seating surface or the fan drive shaft.

(i) Alternative Methods of Compliance (AMOCs)

    The Manager, Engine Certification Office, FAA, has the authority 
to approve AMOCs for this AD, if requested using the procedures 
found in 14 CFR 39.19.

(j) Related Information

    (1) For more information about this AD, 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; e-mail: john.frost@faa.gov.
    (2) Refer to GE Service Bulletin No. CF34-10E S/B 72-0188, for 
related information. Contact GE-Aviation, M/D Rm. 285, One Neumann 
Way, Cincinnati, OH 45215, phone: 513-552-3272; e-mail: 
geae.aoc@ge.com, for a copy of this service information. 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.

    Issued in Burlington, Massachusetts, on October 6, 2011.
Peter A. White,
Manager, Engine & Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 2011-26824 Filed 10-17-11; 8:45 am]
BILLING CODE 4910-13-P
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