[Federal Register Volume 73, Number 172 (Thursday, September 4, 2008)]
[Proposed Rules]
[Pages 51604-51605]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E8-20497]


 ========================================================================
 Proposed Rules
                                                 Federal Register
 ________________________________________________________________________
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 This section of the FEDERAL REGISTER contains notices to the public of 
 the proposed issuance of rules and regulations. The purpose of these 
 notices is to give interested persons an opportunity to participate in 
 the rule making prior to the adoption of the final rules.
 
 ========================================================================
 

  Federal Register / Vol. 73, No. 172 / Thursday, September 4, 2008 / 
Proposed Rules  

[[Page 51604]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2008-0827; Directorate Identifier 2008-NE-26-AD]
RIN 2120-AA64


Airworthiness Directives; General Electric Company (GE) CF6-80A 
Series Turbofan Engines

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for GE CF6-80A series turbofan engines with certain stage 1 high-
pressure turbine (HPT) rotor disks, installed. This proposed AD would 
require removal from service of those stage 1 HPT rotor disks within 30 
days after the effective date of the AD. This proposed AD results from 
the FAA learning that those disks are susceptible to cracks developing 
in the bottoms of the dovetail slots. We are proposing this AD to 
prevent cracks developing in the bottoms of the dovetail slots that 
could propagate to a failure of the disk and cause an uncontained 
engine failure and damage to the airplane.

DATES: We must receive any comments on this proposed AD by November 3, 
2008.

ADDRESSES: Use one of the following addresses to comment on this 
proposed AD.
     Federal eRulemaking Portal: Go to http://www.regulations.gov and follow the instructions for sending your 
comments electronically.
     Mail: Docket Management Facility, U.S. Department of 
Transportation, 1200 New Jersey Avenue, SE., West Building Ground 
Floor, Room W12-140, Washington, DC 20590-0001.
     Hand Delivery: Deliver to mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
     Fax: (202) 493-2251.

FOR FURTHER INFORMATION CONTACT: Tara Chaidez, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803; e-mail: 
[email protected]; telephone: (781) 238-7773, fax: (781) 238-7199.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to send us any written relevant data, views, or 
arguments regarding this proposal. Send your comments to an address 
listed under ADDRESSES. Include ``Docket No. FAA-2008-0827; Directorate 
Identifier 2008-NE-26-AD'' in the subject line of your comments. We 
specifically invite comments on the overall regulatory, economic, 
environmental, and energy aspects of the proposed AD. We will consider 
all comments received by the closing date and may amend the proposed AD 
in light 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 
with FAA personnel concerning this proposed AD. Using the search 
function of the Web site, anyone can find and read the comments in any 
of our dockets, including, if provided, the name of the individual who 
sent the comment (or signed the comment on behalf of an association, 
business, labor union, etc.). You may review the DOT's complete Privacy 
Act Statement in the Federal Register published on April 11, 2000 (65 
FR 19477-78).

Examining the AD Docket

    You may examine the AD docket on the Internet at http://www.regulations.gov; or in person at the Docket Operations office 
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 Operations office (telephone (800) 647-5527) is 
the same as the Mail address provided in the ADDRESSES section. 
Comments will be available in the AD docket shortly after receipt.

Discussion

    During discussions with GE, we recently learned that a population 
of stage 1 HPT rotor disks thought previously to have been retired, may 
still be in service. These disks are subject to cracks developing in 
the bottoms of the dovetail slots that could propagate to a failure of 
the disk. These stage 1 HPT rotor disks, part numbers (P/Ns) 
1380M69G01/G02/G04/G05/G06; 9234M67G12/G13/G14/G15/G16; 9362M58G04; and 
9367M45G01/G03/G05/G06/G07/G08 are not subject to rework or initial 
inspection. This proposed AD would require that all affected stage 1 
HPT rotor disks be removed from service within 30 days after the 
effective date of the AD. This condition, if not corrected, could 
result in cracks developing in the bottoms of the dovetail slots that 
could propagate to a failure of the disk and cause an uncontained 
engine failure and damage to the airplane.

FAA's Determination and Requirements of the Proposed AD

    We have evaluated all pertinent information and identified an 
unsafe condition that is likely to exist or develop on other products 
of this same type design. We are proposing this AD, which would require 
removing the affected stage 1 HPT rotor disks from service within 30 
days after the effective date of the AD.

Costs of Compliance

    We estimate that this proposed AD would affect 3 out of 316 CF6-80A 
series turbofan engines installed on airplanes of U.S. registry. We 
also estimate that it would take about 1 work-hour per engine to 
perform the proposed actions, and that the average labor rate is $80 
per work-hour. Required parts would cost about $300,000 per engine. 
Based on these figures, we estimate the total cost of the proposed AD 
to U.S. operators to be $900,240.

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

[[Page 51605]]

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 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 AD:
    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); 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.
    We prepared a regulatory evaluation of the estimated costs to 
comply with this proposed AD. You may get a copy of this summary at the 
address listed under ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Under the authority delegated to me by the Administrator, the 
Federal Aviation Administration 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:

General Electric Company: Docket No. FAA-2008-0827; Directorate 
Identifier 2008-NE-26-AD.

Comments Due Date

    (a) The Federal Aviation Administration (FAA) must receive 
comments on this airworthiness directive (AD) action by November 3, 
2008.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to General Electric Company (GE) CF6-80A 
series turbofan engines with any of the following stage 1 high-
pressure turbine (HPT) rotor disk part numbers (P/Ns), installed:
    (1) 1380M69G01; 1380M69G02; 1380M69G04; 1380M69G05; or 
1380M69G06; or
    (2) 9234M67G12; 9234M67G13; 9234M67G14; 9234M67G15; or 
9234M67G16; or
    (3) 9362M58G04; or
    (4) 9367M45G01; 9367M45G03; 9367M45G05; 9367M45G06; 9367M45G07; 
or 9367M45G08.
    (d) These CF6-80A series turbofan engines are installed on, but 
not limited to, Airbus A310-200 series and Boeing 767-200 series 
airplanes.

Unsafe Condition

    (e) This AD results from the FAA learning that those discs are 
susceptible to cracks developing in the bottoms of the dovetail 
slots. We are issuing this AD to prevent cracks developing in the 
bottoms of the dovetail slots that could propagate to a failure of 
the disk and cause an uncontained engine failure and damage to the 
airplane.

Compliance

    (f) You are responsible for having the actions required by this 
AD performed within 30 days after the effective date of this AD, 
unless the actions have already been done.
    (g) Remove from service HPT stage 1 rotor disks identified by P/
N in paragraph (c) of this AD.

Prohibition of HPT Stage 1 Rotor Disks

    (h) After the effective date of this AD, do not install any of 
the HPT stage 1 rotor disks, listed by P/N in paragraph (c) of this 
AD into any engine.

Alternative Methods of Compliance

    (i) The Manager, Engine Certification Office, has the authority 
to approve alternative methods of compliance for this AD, if 
requested using the procedures found in 14 CFR 39.19.

Related Information

    (j) Contact Tara Chaidez, Aerospace Engineer, Engine 
Certification Office, FAA, Engine and Propeller Directorate, 12 New 
England Executive Park, Burlington, MA 01803; e-mail: 
[email protected]; telephone: (781) 238-7773, fax: (781) 238-
7199, for more information about this AD.

    Issued in Burlington, Massachusetts, on August 28, 2008.
Marc J. Bouthillier,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. E8-20497 Filed 9-3-08; 8:45 am]
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