DEN05FA002 · Sukhoi SU-29

The Russian-built aerobatic airplane had taken off just prior to the start of the air show. The airplane held outside the show area for a T-33 jet, which was the show's first performance. The pilot then went into his routine. The airplane was approximately 1,500 feet above ground level (agl) when the pilot entered his second maneuver, a torque roll. On reaching its maximum height, the airplane was observed to tail slide and enter an inverted spin. A witness said, "The pilot attempted to recover but didn't make it. The airplane struck the ground upright, in a slight right bank and nose down attitude. On contact with the ground, the airplane exploded and was engulfed in a fireball." Another witness, also one of the air show's performers, described the torque roll. He said that in this maneuver, the airplane pulls up into a vertical climb at full throttle. As the airplane runs out of airspeed, torque from the engine and propeller turns the airplane. The airplane then falls off one direction or the other, nose down, and the pilot flies the airplane out of the dive. The witness said he saw the airplane come out the bottom of the smoke and enter an inverted flat spin. The witness said he saw the airplane make three revolutions. The witness said he thought the pilot had gone too far. "He came off the throttle, the rotation stopped, then the airplane yawed. I heard the engine come in. The airplane came around in a positive attitude. He was getting low. He was upright in a spin. He went to full power. He made a turn and a half and then hit [the ground]." An examination of the airplane revealed no anomalies. A former importer and dealer of SU-29's, who was also a pilot and mechanic who had flown and maintained SU-29's, stated that at the altitude the accident airplane was operating, the pilot cannot reduce power at all during the torque roll maneuver. He said," that if you do reduce power, the airplane will fall off wrong and you will not have enough altitude to recover." Examination of recorded video/images taken of the flight sequence through the ground impact showed the airplane come out of the torque roll into an inverted spin with full left rudder and slight upward elevator controls. The airplane descends in an inverted spin attitude for 3 revolutions before the airplane makes a clockwise roll around its longitudinal axis, placing it in an upright, nose down attitude. About 3.4 seconds prior to the airplane coming out of the inverted attitude, the rudder moves toward neutral. The airplane enters a left downward spiral. At this point, the airplane is less than 600 feet agl. The airplane makes 1.5 left-turning spirals. On completion of the first spiral, the rudder is deflected left and the elevator is deflected upward. At the end of 1.5 spirals, the airplane is approximately 150 feet agl. At this point, the airplane stops its spiral motion and falls straight down to the ground in a 47-degree nose down pitch attitude. On impact, the airplane's rudder shows full right deflection. The elevator is full up (full aft stick deflection).

Verbatim NTSB analysis and probable cause from the NTSB dataset