Progress is fine, but it's gone on for too long.: Testbed

This ex-Air Canada Viscount used in the development of the PT6A-50 turboprop engine model utilized as the powerplant for the de Havilland Canada Dash 7 commuter airliner. The conversion was done by the United Aircraft of Canada, now Pratt and Whitney Canada. The modified plane flew from January to October in 1974.