Witnesses Report Engine Power Loss and Spin During Stall Practice (N9159P)

Witness Observations

Witnesses reported that the pilot and passenger had been discussing practicing stalls. The airplane was observed maneuvering at an altitude of 3,000 feet above the ground when witnesses heard a loss of engine power, followed by an increase, and then another loss of engine power prior to observing the airplane nose down and spinning toward the ground. One witness described the airplane as trying to 'pull out of the maneuver but ran out of altitude and hit the trees and ground.' Another witness described the airplane as 'doing tricks' and 'nose down doing clockwise spins in tight rotation.' The airplane then 'opened up in more of a flat spin like the nose was coming up.' The aircraft descended out of control to ground impact. Prior to impacting the ground, the aircraft also struck several trees.

Post-Crash Examination

During the field examination, the fuel flow divider cover was removed to check for fuel and none was found. During a subsequent engine examination, the upper fuel divider diaphragm was found ruptured. NTSB metallurgists' examination revealed two tears in the diaphragm; however, the time of rupture could not be determined toward substantiating the loss of engine power.