AD/CF6/77 - High Pressure Compressor Rotor

This Airworthiness Directive requires operators to remove GE CF6-80C2B5F engines fitted with the high‑pressure compressor rotor (HPCR) stages 11–14 spool/shaft P/N 1703M74G03 before that shaft reaches 19,500 cycles, and forbids installing any such engine that has accumulated 19,500 cycles or more. It takes effect 5 August 2009. The measure follows a GE audit that found a mismatch in life‑limit documentation and aims to prevent fatigue cracks and possible uncontained spool/shaft failure; it affects operators of aircraft using these engines (eg, some Boeing 747s).