Summary
The FAA proposes to adopt a new airworthiness directive (AD) for all Pratt & Whitney Canada Corp. (P&WC) PT6B-37A model turboshaft engines with engine serial number PCE-PU0289 and earlier. This proposed AD was prompted by a report of contamination from galvanic corrosion between the fuel control unit (FCU) aluminum body and the steel union fitting causing the loss of engine control, resulting in an engine over-speed condition and subsequent in-flight shutdown (IFSD). This proposed AD would require replacing the FCU with a part eligible for installation. The FAA is proposing this AD to address the unsafe condition on these products.