Several additional problems turned up during testing. Stick forces were very low, but this was easily addressed by making the servo tabs 50% larger. A more worrying development was that the engines all had problems with mixture due to changes in engine speed or load, which led to rough engine operation. In August, while Bede was demonstrating the BD-5 (N501BD) to the FAA in order to receive permission to fly at Oshkosh, the engine seized. On its deadstick landing, the aircraft overran the runway, buckling the nose gear. Incorrect mixture was identified as the cause of a second wreck of N501BD, in September 1972, when the mixture control broke and Berven had to execute another forced landing. This landing resulted in damage to all the gear and the fuselage as well.