In 1967 the Swiss AF C-3603 target-towing aircraft still had approximately 10 years of structural life remaining but that the plane's engines were on the verge of wearing out. The most economical solution was to re-engineer the existing aircraft with a turboprop engine necessitating extension of the nose of the aircraft by 1.82 m to maintain the CoG. In total 23 aircraft were converted and this one is on display at Speyer.