Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to General Electric Company (GE) CT58 series turboshaft engines. This proposal would require removal from service of compressor rear shafts, initial and repetitive inspections of ten rotating parts, and replacement if found cracked, until those parts are removed from service and replaced with improved design parts. This proposal is prompted by a stage 2 turbine wheel incident in 1993 which resulted in an increased awareness of small features on critical rotating parts which could affect part life. The actions specified by the proposed AD are intended to prevent fatigue cracking on specific critical rotating parts, which could result in failure of the part, causing an uncontained engine failure and damage to the aircraft.