# AGENCY:

Federal Aviation Administration, DOT. 

# ACTION:

Final rule. 

# SUMMARY:

This amendment adopts a new airworthiness directive (AD), applicable to General Electric Company (GE) CF6-80C2 series turbofan engines. This amendment requires removal from service of affected fan mid shafts prior to reaching a new, lower cyclic life limit, and replacement with serviceable parts. This amendment is prompted by recent component test data. The actions specified by this AD are intended to prevent fan mid shaft failure, which could result in an uncontained engine failure and damage to the aircraft. 

# EFFECTIVE DATE:

April 10, 2000. 

# ADDRESSES:

The service information referenced in this AD may be obtained from General Electric Company via Lockheed Martin Technology Services, 10525 Chester Road, Suite C, Cincinnati, Ohio 45215, telephone 513-672-8400, fax 513-672-8422. This information may be examined at the Federal Aviation Administration (FAA), New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA. 

# FOR FURTHER INFORMATION CONTACT:

William S. Ricci, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; telephone 781-238-7742, fax 781-238-7199. 

# SUPPLEMENTARY INFORMATION:

                    A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to General Electric Company (GE) CF6-80C2 series turbofan engines was published in the                     **Federal Register**                     on October 26, 1999 (64 FR 57608). That action proposed to require removal from service of affected fan mid shafts prior to reaching a new, lower cyclic life limit, and replacement with serviceable parts. That action was prompted by recent component test data. That condition, if not corrected, could result in fan mid shaft failure, which could result in an uncontained engine failure and damage to the aircraft.                 

## Comments Received 

Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received. 

Two commenters concur with the rule as proposed. 

## Conclusion 

After careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule as proposed. 

## Economic Analysis 

There are approximately 1,796 engines of the affected design in the worldwide fleet. The FAA estimates that 230 engines installed on aircraft of US registry will be affected by this AD and that required parts will cost approximately $90,085 per engine. Based on these figures, the total cost impact of the AD on US operators is estimated to be $20,719,600. 

## Regulatory Impact 

The regulations adopted herein 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. Therefore, it is determined that this final rule does not have federalism implications under Executive Order (EO) 13132. 

                    For the reasons discussed above, I certify that this action (1) Is not a “significant regulatory action” under EO 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. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption                     **ADDRESSES**                    .                 

# List of Subjects in 14 CFR Part 39

- Air transportation
- Aircraft
- Aviation safety
- Safety

## Adoption of the Amendment 

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (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. Section 39.13 is amended by adding the following new airworthiness directive: 

**2000-03-04 General Electric Company:**                             Amendment 39-11561. Docket 98-ANE-79-AD.                         

*Applicability:*                             General Electric Company (GE) CF6-80C2 series turbofan engines, with fan mid shafts, part number (P/N) 9326M74P04 or P/N 9326M74P05, installed. These engines are installed on but not limited to Airbus Industrie A300 and A310 series, Boeing 747 and 767 series, and McDonnell Douglas MD-11 series aircraft.                         

# Note 1:

This airworthiness directive (AD) applies to each engine identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For engines that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (c) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

*Compliance:*                             Required as indicated, unless accomplished previously.                         

To prevent fan mid shaft failure, which could result in an uncontained engine failure and damage to the aircraft, accomplish the following: 

(a) Remove from service affected fan mid shafts and replace with a serviceable part, as follows: 

# Note 2:

GE CF6-80C2 Service Bulletin (SB) No. 72-958, dated December 10, 1998, contains information on this subject.

(1) For fan mid shafts that have accumulated 9,000 or more cycles-since-new (CSN) on the effective date of this AD, remove from service within 3,500 cycles-in-service (CIS) after the effective date of this AD, or prior to accumulating 15,000 CSN, whichever occurs first. 

                            (2) For fan mid shafts that have accumulated 1,800 CSN or more, but less                             Start Printed Page 6534                            than 9,000 CSN on the effective date of this AD, remove from service within 5,000 CIS after the effective date of this AD, or prior to accumulating to 12,500 CSN, whichever occurs first.                         

(3) For fan mid shafts that have accumulated less than 1,800 CSN on the effective date of this AD, remove from service prior to accumulating 6,800 CSN. 

# Note 3:

GE CF6-80C2 SB 72-750, Revision 2, dated September 4, 1998, contains information on reworking fan mid shafts that results in changing the P/N. After that rework, this AD would not apply to engines containing the reworked fan mid shaft.

## New Life Limits 

(b) Except for the provisions of paragraph (a) of this AD, no fan mid shafts, P/N 9326M74P04 or 9326M74P05, may remain in service beyond 6,800 CSN. 

## Alternate Method of Compliance 

(c) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Engine Certification Office (ECO). Operators shall submit their request through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, ECO. 

# Note 4:

Information concerning the existence of approved alternative methods of compliance with this airworthiness directive, if any, may be obtained from the ECO.

## Ferry Flights 

(d) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the aircraft to a location where the requirements of this AD can be accomplished. 

(e) This amendment becomes effective on April 10, 2000.

Issued in Burlington, Massachusetts, on February 2, 2000. 

David A. Downey, 

Assistant Manager, Engine and Propeller Directorate, Aircraft Certification Service. 

[FR Doc. 00-2988 Filed 2-9-00; 8:45 am] 

BILLING CODE 4910-13-U