After a good showing at the 1974 Canadian Grand Prix, Koinigg was beginning to establish himself as a good prospect for 1975. But running near the back in the US Grand Prix at Watkins Glen, Koinigg's car suffered a suspension failure at turn 7, pitching it head-on into the Armco barrier. The speed at which Koinigg crashed was relatively low, and he ought to have escaped the accident uninjured. However, as with a number of other circuits at that time, the Armco was insecurely installed and the bottom portion of it buckled as the vehicle struck it. The car passed underneath the top portion, which remained intact, decapitating Koinigg and killing him instantly. Koinigg's accident was reminiscent of the death of Formula One driver François Cevert at the same track the previous year.