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

[Federal Register Volume 74, Number 69 (Monday, April 13, 2009)]
[Rules and Regulations]
[Pages 16754-16755]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E9-8263]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2008-0827; Directorate Identifier 2008-NE-26-AD; 
Amendment 39-15879; AD 2009-08-06]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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

DATES: This AD becomes effective May 18, 2009.

ADDRESSES: The Docket Operations office is located at Docket Management 
Facility, U.S. Department of Transportation, 1200 New Jersey Avenue, 
SE., West Building Ground Floor, Room W12-140, Washington, DC 20590-
0001.

FOR FURTHER INFORMATION CONTACT: Robert Green, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803; e-mail: 
[email protected]; telephone: (781) 238-7754, fax: (781) 238-7199.

SUPPLEMENTARY INFORMATION: The FAA proposed to amend 14 CFR part 39 
with a proposed AD. The proposed AD applies to GE CF6-80A series 
turbofan engines with certain stage 1 HPT rotor disks, installed. We 
published the proposed AD in the Federal Register on September 4, 2008 
(73 FR 51604). That action proposed to require removal from service of 
those stage 1 HPT rotor disks within 30 days after the effective date 
of the AD.

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 AD, the regulatory evaluation, 
any comments received, and other information. The street address for 
the Docket Operations office (telephone (800) 647-5527) is provided in 
the ADDRESSES section. Comments will be available in the AD docket 
shortly after receipt.

Comments

    We provided the public the opportunity to participate in the 
development of this AD. We have considered the comment received.

Claim That Cost of Compliance Is Underestimated

    One commenter, FedEx Express, claims that we greatly underestimated 
the actual cost of compliance with the proposed AD. The proposed AD 
estimated 1 work-hour of labor. The commenter states that this estimate 
is accurate only when the engine is already removed and disassembled to 
piece-part exposure of the disk. The commenter states that the true 
cost to an airline, both in disruption to the operation and in the 
subsequent unplanned engine shop visit, would vastly exceed 1 work-
hour.
    We agree that the cost of compliance should also cover the work-
hours for an unplanned engine shop visit. We do not agree that it 
should factor in the cost of disruption to the operation. We are 
required to calculate only the direct cost to an operator, of labor and 
parts. We changed the cost of compliance paragraph to include an 
estimate for an unplanned engine shop visit.

Clarification of Unsafe Condition Statement

    Since we issued the proposed AD, we clarified the unsafe condition 
statement as to where potential cracks could occur in the disk. We 
changed ``cracks developing in the bottoms of the dovetail slots'' to 
``cracks developing at the aft chamfer of the blade dovetail slots.''

Conclusion

    We have carefully reviewed the available data, including the 
comment received, and determined that air safety and the public 
interest require adopting the AD with the changes described previously. 
We have determined that these changes will neither increase the 
economic burden on any operator nor increase the scope of the AD.

[[Page 16755]]

Costs of Compliance

    We estimate that this AD will affect 3 out of 316 CF6-80A series 
turbofan engines installed on airplanes of U.S. registry. We also 
estimate that it will take about 1 work-hour per engine to perform the 
actions if the engine is already removed and disassembled to piece-part 
exposure of the disk, and will take about 115 work-hours per engine for 
an unplanned engine shop visit. 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 AD to U.S. operators 
to be $927,600.

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); and
    (3) 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.
    We prepared a summary of the costs to comply with this AD and 
placed it in the AD Docket. 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.

Adoption of the Amendment

0
Accordingly, under the authority delegated to me by the Administrator, 
the Federal Aviation Administration amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
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]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive:

2009-08-06 General Electric Company: Amendment 39-15879. Docket No. 
FAA-2008-0827; Directorate Identifier 2008-NE-26-AD.

Effective Date

    (a) This airworthiness directive (AD) becomes effective May 18, 
2009.

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 and -300 series 
airplanes.

Unsafe Condition

    (e) This AD results from the FAA learning that those disks are 
susceptible to cracks developing at the aft chamfer of the blade 
dovetail slots. We are issuing this AD to prevent cracks developing at 
the aft chamfer of the blade 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 Robert Green, Aerospace Engineer, Engine Certification 
Office, FAA, Engine and Propeller Directorate, 12 New England Executive 
Park, Burlington, MA 01803; e-mail: [email protected]; telephone: 
(781) 238-7754, fax: (781) 238-7199, for more information about this 
AD.

Material Incorporated by Reference

    (k) None.

    Issued in Burlington, Massachusetts, on April 6, 2009.
Peter A. White,
Assistant Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. E9-8263 Filed 4-10-09; 8:45 am]
BILLING CODE 4910-13-P

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