THE PILOT HAD LOGGED 4 HOURS AS PILOT IN COMMAND SINCE BEING ENDORSED FOR SOLO FLYING 6 DAYS BEFORE THE ACCIDENT FLIGHT. DURING THE ACCIDENT FLIGHT HE PERFORMED 6 TAKEOFFS AND LANDINGS. DURING THE 7TH LANDING THE AIRPLANE TOUCHED DOWN HARD. THE NOSE GEAR ASSEMBLY BUCKLED AND THE AIRPLANE NOSED OVER.