Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to General Electric Company CT58 series turboshaft engines. This proposal would require removal from service of certain stage 1 and 2 forward cooling plates, and stage 2 aft cooling plates, and replacement with serviceable parts. This proposal is prompted by reports of certain cooling plates forged with contaminated alloy that could reduce the lives of the parts. The actions specified by the proposed AD are intended to prevent cooling plate fracture, which could result in a contained engine failure, and an inflight engine shutdown.