On August 9, 2000, at 1832 Pacific daylight time, a Cessna 152, N6434H, registered to and operated by Hillsboro Aviation as a 14 CFR Part 91 instructional flight, collided with the ground short of the runway 02 at Hillsboro, Oregon. Visual meteorological conditions prevailed at the time and no flight plan was filed for the local flight. The aircraft was substantially damaged. The flight instructor was seriously injured, while the student pilot received minor injuries. The student pilot reported that 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 100-150 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. The aircraft collided with the ground about 200 feet short of the end of the runway and slid about 60 feet before coming to rest. In a written statement that was attached to the NTSB Pilot/Operator Aircraft Accident Report Form 6120.1/2, which was signed by the school director from Hillsboro Aviation, it indicated that, "It is believed wake turbulence from the helicopters may have contributed to the accident." The Federal Aviation Administration Inspector from the Portland-Hillsboro Flight Standards District Office responded to the accident site. The inspector reported that control continuity was established throughout the flight control system. No evidence of a mechanical failure or malfunction was found.