On March 31 2004, about 1255 Pacific standard time, a Piper PA-34-200, N74SA, collided with terrain while attempting a go-around at Brackett Field Airport, La Verne, California. Air Desert Pacific was operating the airplane under the provisions of 14 CFR Part 91. The certified flight instructor (CFI) and student pilot were not injured; the airplane sustained substantial damage. The local instructional flight originated from La Verne about 1150. Day visual meteorological conditions prevailed, and a flight plan had not been filed. In a written statement, the CFI reported that he was overseeing the student's landing attempt on runway 26R. While inbound, about 4,000 feet mean sea level, the CFI turned the right engine fuel selector to the "off" position, in an effort to simulate an engine failure. The student followed the proper procedure by correctly identifying the failed engine and positioning the left throttle, mixture, and propeller controls in their full forward position, and the right throttle control in the idle position. While on the downwind portion of the traffic pattern, the air traffic control tower cleared them to land on runway 26L. On final approach, the student configured the airplane with full flaps and the landing gear in the extended position. On short final, about 100 feet above ground level, the airplane was high and not properly aligned with the runway. The CFI opted to make a go-around, and the student inputted full throttle on both engines. The student was unable to maintain airspeed and establish a positive rate of climb. The CFI communicated that he would take over the controls, and attempted to continue the go-around. The airplane would not climb and drifted to the right, across runway 26R. The airplane continued in a gradual decent, and the stall warning horn sounded. The right wing impacted terrain, and the airplane spun around on the ground. The CFI stated that he had become distracted, and did not remember to turn the fuel selector back to the "on" position after the student had identified the failed engine while inbound. He thought this was the reason that the right engine did not respond to the throttle input during the go-around. He added that it was possible that he could not maintain directional control of the airplane because the student may have failed to relinquish the controls. The CFI reported no preimpact mechanical malfunctions or failures with the airplane.