THE AIRPLANE WAS OBSERVED TO ABRUPTLY PITCH NOSE DOWN ON FINAL APPROACH. THE SOLO STUDENT PILOT AT THE CONTROLS HAD LOGGED ABOUT 28 HOURS TOTAL FLIGHT EXPERIENCE. ACCORDING TO THE STUDENT PILOT'S FLIGHT INSTRUCTOR, TWO HOURS OF DUAL INSTRUCTION WERE DEVOTED TO FLIGHT AT MINIMUM CONTROLLABLE AIRSPEED. THE AIRPLANE FLAPS WERE DETERMINED TO BE IN TRANSIT AT THE TIME OF IMPACT. THE FLAP JACKSCREW MECHANISM INDICATED THE FLAPS TO BE AT AN INTERMEDIATE POSITION OF 7 DEGREES WHILE THE FLAP HANDLE INDICATED 10 DEGREES. THE FLAPS SHOULD BE SET FOR LANDING BY THE TIME THE AIRPLANE HAD REACHED ITS POSITION ON FINAL APPROACH. THE STUDENT PILOT WAS IN RADIO CONTACT WITH THE CONTROL TOWER. THERE WERE NO REPORTS BY THE STUDENT PILOT OF ANY PROBLEMS WITH THE AIRPLANE. THERE WERE NO MECHANICAL FAILURES OR MALFUNCTIONS FOUND WITH THE AIRPLANE DURING THE WRECKAGE EXAMINATION.