1) FATIGUE FAILURE OF THE ENGINE CRANKSHAFT AT THE NUMBER 2 MAIN JOURNAL DUE TO UNDETERMINED REASON (S) WHICH RESULTED IN THE TOTAL LOSS OF ENGINE POWER, AND 2) THE PILOT NOT MAINTAINING AN ADEQUATE AIRSPEED WHICH RESULTED IN AN INADVERTENT STALL/SPIN. A FACTOR IN THIS ACCIDENT WAS INADEQUATE ALTITUDE FOR THE PILOT TO RECOVER FROM THE STALL/SPIN.