Accident Overview
A Piper PA-28-140, operated by a flight school, overran the end of the runway during an aborted takeoff. The accident occurred while a certificated flight instructor (CFI) was demonstrating a ground effect acceleration takeoff to a student pilot. The takeoff was conducted on runway 08, with the wind from 250 degrees at 9 knots.
Flight Details
The CFI reported that the airplane did not accelerate in ground effect to the target speed of 90 miles per hour (mph). He initiated an aborted takeoff approximately 1,500 feet before the end of the runway. Upon touchdown, the CFI noted poor braking action. He reduced back pressure, applied brakes firmly, then reapplied back pressure, but the airplane did not stop. The airplane departed the runway end at about 70 mph.
The student pilot stated that the CFI cut power immediately and began to flare. When it was evident the aircraft was not slowing sufficiently, the instructor dropped the nose and both pilots applied full brakes.
Witness Account
The airport manager, who witnessed the accident, reported that the airplane was about 10 feet above the runway when it settled back to the runway. He stated that the airplane was still under full power all the way to the white marks at the end of runway eight. The engine power was then reduced, and the airplane skidded between the runway end lights. The manager noted a continuous cloud of blue smoke from the point of impact to where the throttle was fully retarded.
Final Position and Evidence
The airplane came to rest in the grass approximately 250 feet beyond the departure end of the runway. Black skid marks and metallic scrape marks were visible on the runway, beginning about 300 feet prior to the departure end and continuing to the runway end.
Pilot Information
The CFI held a current certificate, and the student pilot was receiving instruction. No further information about their qualifications is available.
Aircraft Performance Considerations
The density altitude at the time of the takeoff was 8,110 feet. The Piper PA-28-140 Owner's Handbook includes a takeoff distance versus density altitude chart that provides data up to 7,000 feet. The chart states that extrapolation above 7,000 feet is invalid. The landing distance versus density altitude chart indicates that at 7,000 feet density altitude, with 40 degrees of flaps, at gross weight and no wind, the landing distance would be 1,250 feet.
Probable Cause
The investigation report does not state a probable cause.