Applicability: CF6-50 and -80C2 Series turbofan engines identified by serial number in GE Alert Service Bulletins, GE CF6-50 SB 72-A1139 and CF6-80C2 SB 72-A906, dated 17 October 1997.

Requirement: Remove from service HPCR 3-9 spools identified by serial number in the appropriate service bulletin and replace with serviceable parts as follows:

(1) For GE CF6-50 series turbofan engines, remove and replace in accordance with GE CF6-50 SB 72-A1139, dated 17 October 1997.

(2) For GE CF6-80C2 series turbofan engines, remove and replace in accordance with GE CF6-80C2 SB A906, dated 17 October 1997.

Note: US FAA AD 97-22-14, amendment 39-10186, dated 17 November 1997 applies.

Compliance: Within 30 days of the effective date of this directive.

This airworthiness directive becomes effective on 20 November 1997.

Background: Separation of the high pressure compressor rotor (HPCR), stages 3-9 spool has been experienced recently and traced to a manufacturing fault. The spools affected have been identified by serial number and are now being withdrawn from service and replaced at the manufacturer’s expense (including manpower costs).