Summary
We propose to revise an existing airworthiness directive (AD) that applies to the products listed above. The existing AD currently requires removing from service certain gas generator second stage turbine discs, part number (P/N) 0 292 25 040 0, that are not marked with "CFR'' before the discs exceed 2,500 cycles-in-service (CIS) since-new or within 20 CIS from the effective date of the AD, whichever occurs later. That AD also requires removing from service certain gas generator second stage turbine discs, P/N 0 292 25 040 0, that are marked with "CFR'' before the discs exceed 3,500 CIS since-new. Since we issued that AD, Turbomeca has restored all or part of the life limits of the affected discs, and the European Aviation Safety Agency (EASA) issued AD 2010-0101R2, dated March 24, 2011 to do the same. This proposed AD would still prevent disc failure but extends the life limits of the affected discs. We are proposing this AD to prevent failure of the gas generator second stage turbine disc which could result in the release of high energy debris and damage to the helicopter.