Two days later, another biplane, this one an 85 percent replica of a Curtiss FIIC-2 Goshawk, a vintage fighter and dive bomber, crashed. The airplane, which had never before flown, was equipped with a nine-cylinder, 280-hp Lycoming R-680 radial engine. Near the end of what was supposed to be a taxi test on the runway, the engine surged and the airplane became airborne, veered to the left, stalled and crashed, killing the front-seat builder-pilot. The rear-seat passenger, a 9,000-hour ATP, who survived, told investigators that he had had no intention of flying in the airplane, which in his opinion was unsafe because "the ailerons did not have full travel and … the strakes were hitting the flying wires." It appeared that the surging of the engine might have been due to a buildup of oil residue on the propeller governor drive shaft, which caused it to stick. Post-mortem examination of the pilot revealed residues of Tylenol and Benadryl in his blood. Benadryl was found by one medical study to have a more adverse effect on driving performance than alcohol. The NTSB report does not specify the amount of each substance needed to achieve similar results.