Custer County Airport
Aircraft Accident/Incident Report

Custer, South Dakota 57730
Saturday, July 31, 2004 9:50 MDT

The airplane collided with rough terrain when it overran the end of the runway during an aborted takeoff. The certificated flight instructor (CFI) was demonstrating a "ground effect acceleration takeoff" when the accident occurred. The CFI stated the airplane did not accelerate in ground effect to his target speed of 90 miles per hours so he initiated an aborted takeoff about 1,500 feet prior to the end of the runway. The CFI stated that upon touchdown, the braking action was poor. He stated he reduced back pressure and applied brakes firmly, before applying back pressure again, but the airplane did not stop. The CFI stated the airplane departed the end of the runway at a speed of about 70 mph. The student pilot stated the CFI "... cut power immediately, and began to flare. When it was evident that the aircraft was not slowing at a sufficient rate, the instructor dropped the nose and both instructor and student applied full brakes." The airport manager who witnessed the accident reported the airplane was about 10 feet above the runway when it settled back to the runway. He stated the airplane was "... still under full power all the remaining way to the white marks at the end of runway eight." He stated the engine power was then reduced and the airplane skidded between the runway end lights. The manager stated, "From the point of impact to the point where the throttle was fully retarded, there was a continuous cloud of blue smoke." The airplane came to rest in the grass approximately 250 feet from the departure end of the runway. Black skid marks and metallic scrape marks were visible on the runway. These marks began about 300 feet prior to the departure end of the runway and continued to the end of the runway. Density altitude at the time of the takeoff was 8,110 feet. The takeoff was being made on runway 08 and the wind was from 250 degrees at 9 knots. The PA-28-140 Owner's Handbook provides a takeoff distance versus density altitude chart. The chart contains information for density altitudes up to 7,000 feet. The chart states "Extrapolation of chart above 7000 ft. is invalid." The landing distance versus density altitude chart indicates that at a density altitude of 7,000 feet, with 40 degrees of flaps, at gross weight with no wind, the landing distance would be 1,250 feet.

The pilot's poor preflight planning/preparation and the pilot used improper aborted takeoff procedures by not reducing the throttle. Factors associated with the accident were the high density altitude and the tailwind.