1) THE PILOT'S INADVERTENT ENTRY INTO INSTRUMENT METEOROLOGICAL CONDITIONS, 2) HIS FAILURE TO MAINTAIN CONTROL OF THE AIRCRAFT DUE TO SPATIAL DISORIENTATION, 3) THE INADVERTENT ENTRY INTO A SPIRAL DIVE AT AN EXCESSIVE AIRSPEED, AND, 4) THE PILOT'S IMPROPER USE OF THE FLIGHT CONTROLS WHICH IMPOSED EXCESSIVE LOADS ON THE AIRFRAME DURING THE ATTEMPTED RECOVERY FROM THE SPIRAL DIVE.