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###### Department of Transportation

###### Federal Aviation Administration

          - 14 CFR Part 39
          - [Docket No. 90-ANE-25-AD]

# AGENCY:

Federal Aviation Administration, DOT.

# ACTION:

Proposed rule; withdrawal.

# SUMMARY:

This action withdraws a notice of proposed rulemaking (NPRM) that proposed to revise an existing airworthiness directive (AD), applicable to GE CF6-45 and CF6-50 series turbofan engines. That action would have revised an existing AD to require the same inspections on reworked high pressure compressor (HPC) rear shafts as those HPC rear shafts covered by the current amendment. That proposal was prompted by the need to ensure that the additional reworked HPC rear shafts receive the same inspections as part numbers covered by the current amendment. Since that NPRM was issued, the FAA has determined that the repetitive inspections of reworked HPC rear shafts will instead be incorporated into the final rule, AD 2001-12-20, for a new design HPC air duct. Accordingly, the proposed rule is withdrawn.

# FOR FURTHER INFORMATION CONTACT:

Karen Curtis, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; telephone (781) 238-7192; fax (781) 238-7199.

# SUPPLEMENTARY INFORMATION:

                    A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to revise an existing AD, applicable to GE CF6-45 and CF6-50 series turbofan engines, was published in the                     **Federal Register**                     on October 12, 2000 (65 FR 60597). The proposed rule would have revised AD 91-10-03, R1, to add HPC rear shaft rework P/N's to the AD. That action was prompted by the need to ensure that the additional HPC rear shafts receive the same inspections as part numbers covered by the current amendment. The proposed actions were intended to detect and replace cracked HPC rear shafts, which, if not replaced, could lead to an uncontained engine failure.                

The FAA received a comment that notes that a new effective date of the AD revision could be misconstrued and result in parts continuing in service without the required inspections, for longer than originally intended by the current AD.

                    The FAA agrees. Upon further consideration, the FAA has determined that the proposed addition of repetitive inspections of reworked HPC rear shafts will instead be incorporated into the final rule for a new design HPC air duct. The final rule for the new design air duct, AD 2001-12-20, requires that existing HPC rear shafts be reworked for compatibility with new design air ducts, inspected at the time of rework, and repetitively inspected at specified                           ( print page 33215)                        intervals. As a result, revising the existing AD is no longer required. Accordingly, the proposed rule is hereby withdrawn.                

Withdrawal of this notice of proposed rulemaking constitutes only such action, and does not preclude the agency from issuing another notice in the future, nor does it commit the agency to any course of action in the future.

Since this action only withdraws a notice of proposed rulemaking, it is neither a proposed nor a final rule and therefore, is not covered under Executive Order 12866, the Regulatory Flexibility Act, or DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979).

# List of Subjects in 14 CFR Part 39

      - Air transportation
      - Aircraft
      - Aviation safety
      - Safety

## The Withdrawal

                    Accordingly, the notice of proposed rulemaking, Docket 90-ANE-25-AD, published in the                     **Federal Register**                     on October 12, 2000, (65 FR 60597), is withdrawn.                

Issued in Burlington, Massachusetts, on June 14, 2001.

Robert J. Ganley,

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

[FR Doc. 01-15574 Filed 6-20-01; 8:45 am]

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