At 18:32 Pacific time, a Cessna 152 struck the ground short of the runway, seriously injuring the flight instructor and leaving the student pilot with minor injuries. The student said the aircraft was trailing about 30 seconds behind two Life Flight helicopters (Bell 230 and BK 117) on final approach to runway 02. After the helicopters crossed over the airport boundary fence (about 500 feet before the end of the runway) they made a right turn for landing on the ramp. The student stated that he was on the controls at the time, and at about 100 feet above ground level and 60 knots, the aircraft suddenly rolled to the right about 90 degrees. The flight instructor took over the controls and righted the aircraft, however, it continued to settle to the ground in a nose down attitude.