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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

# AGENCY:

Federal Aviation Administration (FAA), DOT.

# ACTION:

Final rule.

# 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:                         *robert.green@faa.gov*; 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.                          ( print 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

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

1. The authority citation for part 39 continues to read as follows: 

Authority:49 U.S.C. 106(g), 40113, 44701.

§ 39.13

2. The FAA amends § 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:                         *robert.green@faa.gov*; 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