On June 18, 2000, at 1050 Eastern Daylight Time, a Piper PA-38, N407DS, was substantially damaged when it landed short of the runway at Delaware Airpark (33N), Cheswold, Delaware. The certificated flight instructor and the certificated student pilot were uninjured. Visual meteorological conditions prevailed at the time of the accident. No flight plan had been filed for the local instructional flight, which was conducted under 14 CFR Part 91. According to the flight instructor, the airplane was on a stabilized final approach to Runway 27, at 65 knots indicated airspeed, with the student at the controls. The student reduced power, the airspeed went below 60 knots, and airplane began to "sink." The instructor told the student to watch his airspeed, "but no corrective action was taken." At that point, with the airplane about 200 feet above the ground, the instructor initiated a go-around. However, on short final, "the student observed the airspeed slow and pushed over the control wheel drastically...the student was pushing forward while I was pulling aft and adding power." The instructor further stated that the student overcame the instructor's inputs, and that the left main landing gear became entangled in tall grass and brush. The airplane yawed to the left and was pulled downwards. It impacted the ground, skidded sideways, and came to rest 20 to 30 feet prior to the runway threshold. According to the student pilot, the airplane was high on final approach, so he reduced power. When he thought he had the runway made, the student reduced additional power, "which caused the airspeed to decrease too much. The instructor took the controls, but it was too late [and] we were too low...."