AD NUMBER: 2004-17-03
MANUFACTURER: Pratt & Whitney
SUBJECT: Airworthiness Directive 2004-17-03
SUMMARY: The FAA is superseding an existing airworthiness directive (AD) for Pratt & Whitney Canada (PWC) PW206A and PW206E turboshaft engines. That AD currently requires:. Initial and repetitive borescope inspections of compress or turbine and power turbine blades forblade axial shift.. Replacement of blade retaining rivets and certain rotor air seals as terminating action for the repetitive borescope inspections.This ad requires the same actions as AD 2003-NE-25-AD but the extent of engine disassembly that triggers the required part replacements needs clarification. This AD results from reports ofengine shutdowns and emergency landings due to severe vibration, resulting in exhaust gases escaping from the engine-to-exhaust nozzle interface, there by triggering in-flight engine firewarnings. We are issuing this AD to prevent turbine blade axial shift, which could cause highlevels of vibration, loss of engine torque, in-flight engine shutdown, and loss of the airframe exhaust duct.

FMI: http://www.avantext.com/DailyADIndex.ASP?AD=20041703