Accident Sequence
The commercial pilot was flying a single-engine airplane and reported being 7 or 8 miles from the arrival airport at 8,500 feet MSL, inbound for landing. The controller asked if the pilot could descend from that position, to which the pilot responded, "Yeah, if I could do right traffic, I'll go into a imitation of a rock, see what I can do." The controller then instructed the pilot to enter a left downwind leg at midfield and provided wind conditions: 270 degrees at 25 knots.
Witness Observations
Several witnesses within a mile of the accident site reported observing the airplane in a steep, nose-down attitude with a rapidly increasing rate of descent. The airplane maintained a perpendicular, nose-down orientation until it disappeared behind low scrub brush. At approximately the same time, witnesses saw a dust cloud rise in the vicinity, which quickly dissipated in the gusting surface winds.
Radar Data
The airplane's Mode C radar data showed a descent rate of 5,500 feet per minute between the last two radar returns, which were 12 seconds apart. The final radar return indicated the airplane at 4,900 feet MSL, or 2,545 feet above the ground.
Pilot's Descent Procedure
Co-workers described that the mishap pilot used a specific procedure to lose altitude quickly: reduce power and slow the airplane to 120 knots, position the propeller control full forward, allow engine temperatures to normalize, and trim the airplane nose down to achieve an indicated airspeed near Vne (176 knots, the never-exceed speed). It was reported that the pilot learned this technique from other pilots who transported parachutists.
Post-Accident Examination
Examination of the airframe and engine revealed no pre-accident anomalies. All main wings and fixed and movable primary and secondary control surfaces were accounted for at the impact site. No evidence of physiological incapacitation was found. Investigators considered the possibility that a combination of airplane attitude and speed could have aerodynamically blanked the empennage surfaces, but no supporting evidence was discovered.