Overview
A non-certificated pilot took a multiengine airplane without the owner's permission and attempted to fly the traffic pattern. During the approach, on base leg to final, the airplane was observed to stall, enter a nose-down descent, and crash.
Events
The pilot, who did not hold a valid certificate, operated the airplane without authorization. The flight was limited to the traffic pattern. As the airplane turned from base leg to final approach, it lost lift and descended nose-first before impacting the ground.
Preflight Condition
Before the flight, the static system ports had been taped over to facilitate avionics maintenance. The non-certificated pilot was apparently unaware of this condition and did not ensure the ports were clear during the preflight inspection.
Probable Cause
The official probable cause was the failure of the non-certificated pilot (an unqualified person) to maintain sufficient airspeed, leading to an aerodynamic stall and collision with terrain. Contributing factors included the pilot's unauthorized use of the airplane, the static ports being taped for maintenance, and the pilot's failure to conduct an adequate preflight inspection to verify the static ports were clear.