On June 2, 2001, about 0800 hours mountain standard time, a Beech 76, N6046U, sustained substantial damage during a hard landing at Prescott, Arizona. Embry Riddle Aeronautical University was operating the airplane under the provisions of 14 CFR Part 91. The certified flight instructor and the private pilot certificated dual student were not injured. The local instructional flight departed Prescott about 0705. Visual meteorological conditions prevailed, and no flight plan had been filed. According the flight instructor, the student's previous two landings were "allright" except his final approaches were low. The flight instructor asked the student to make a short field landing and to "keep his glide a little high." On this approach, as the airplane neared the threshold, the student began to pull the power back and bring the nose up. The flight instructor told the student to "keep it down just a little longer." Again, the student retarded the power and raised the nose, and the instructor ordered a go-around. The student's reaction was slow and the instructor said "go-around" again. She then pushed the throttles forward herself but the airplane was sinking rapidly. The airplane landed hard and bounced. Both propellers struck the runway, both wings buckled in the flap hinge area, and a firewall buckled.