According to the flight instructor, the student pilot was landing on the 2,903-foot by 60-foot runway 29 with winds from 320 degrees true at 4 knots. The approach was "seemingly normal," with the airplane trimmed for an approach airspeed of 62 knots, and configured with approximately one-half flaps. About 15 to 20 feet above the runway, with no pre-stall indication or buffeting noted, the airplane suddenly dropped, then impacted the runway. The airplane then veered off the left side of the runway, and the right wing was substantially damaged when it impacted a precision approach path indicator (PAPI) stanchion. The flight instructor did not report any preexisting mechanical anomalies with the airplane.