Airworthiness Directives; Pratt & Whitney Canada Corp. Turboprop Engines

We propose to adopt a new airworthiness directive (AD) for certain Pratt & Whitney Canada Corp. (PWC) PT6A-60AG, -65AG, -67AF, and -67AG turboprop engines. This proposed AD was prompted by incidents of corrosion and perforation of the two-ply Cu-Be bellows in Woodward fuel control units (FCUs). This proposed AD would require removing the Woodward FCU and installing an FCU that is eligible for installation. We are proposing this AD to prevent failure of the Woodward FCU, which could lead to failure of the engine, in-flight shutdown, and loss of control of the airplane.