Airworthiness Directives; General Electric Company CT58 Series and Surplus Military T58 Series Turboshaft Engines

The FAA is adopting a new airworthiness directive (AD) for General Electric Company (GE) CT58-140-1, CT58-140-2, and surplus military T58-GE-5, -10, -100, and -402 turboshaft engines with certain serial numbers (SNs) of stage 1 compressor disks, part number (P/N) 5001T20P01, installed. This AD requires removing certain stage 1 compressor disks from service before reaching a reduced low-cycle- fatigue (LCF) life limit for those affected disks of 2,100 hours time- since-new (TSN) or by December 31, 2008, whichever occurs first. This AD results from two reports of low blade tip clearances in the compressor. We are issuing this AD to prevent LCF cracking and failure of the stage 1 compressor disk, an uncontained engine failure, and damage to the helicopter.