AD NUMBER: 2010-17-01

MANUFACTURER: Pratt & Whitney Canada Corp. PW617F-E Turbofan Engines
SUBJECT: Airworthiness Directive 2010-17-01

SUMMARY: This AD results from mandatory continuing airworthiness information (MCAI) issued by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as:

A PW617F-E engine powered twin engined aircraft had recently experienced an uncommanded power reduction on one of its engines. Investigation showed that the Fuel Filter Bypass Valve poppet in the Fuel Oil Heat Exchanger (FOHE) on that engine had worn through the housing seat, allowing unfiltered fuel and debris to contaminate the Fuel Metering Unit (FMU), resulting in fuel flow drop and subsequent power reduction.  Pratt & Whitney Canada Corp. issued an Alert Service Bulletin (ASB) No. PW600-72-A66019 to inspect and replace any discrepant valve with the same type new valve. The inspection results confirmed that failure of a worn through poppet is dormant and it can affect both engines at the same time that could result in an unsafe condition on PW617F-E powered aircraft. 

The FAA is issuing this AD to prevent uncommanded power reduction, which could result in the inability to continue safe flight and safe landing.

FMI: http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAD.nsf/0/0A16403C9183FB9086257788004C7196?OpenDocument