Accident Overview
On July 25, 2020, about 1136 mountain daylight time, an Air Tractor AT-502B airplane, registration N502KJ, was substantially damaged when it impacted terrain near Grant, Nebraska. The pilot, who was the sole occupant, was fatally injured. The airplane was being operated under Title 14 Code of Federal Regulations Part 137 as an agricultural flight.
Flight History
Data from the airplane's Satloc GPS guidance system showed the flight departed Grant Municipal Airport (GGF) at 1108 and proceeded south to the field to be sprayed. After several orbits, the pilot began spraying using east/west flightpaths. As the flight progressed, the airplane made climbing left turns after each spray pass, with the frequency of passes increasing and the elapsed time between passes decreasing. The maximum altitude between passes also increased. During the final 5 minutes, groundspeed was 160–165 mph on spray passes and 104–120 mph during turns, with climbs of 450–520 ft after each pass.
The final GPS track point at 1136:48 recorded the airplane climbing west at the northern edge of the field, about 1/4 mile northeast of the accident site, with a groundspeed of 152 mph and estimated altitude of 136 ft above ground level. The system's 6-second delay between data acquisition and storage meant the final moments were not recorded.
Witness Observation
Another agricultural pilot spraying a nearby field reported radio contact with the accident pilot throughout most of the flight. He stated the accident airplane consistently climbed 450–500 ft after each spray pass, higher than required. The last time he saw the airplane, it was climbing west before rolling right-wing-down into a 90°–100° bank with a 10°–12° nose-up pitch attitude, then turning north and pitching down through the horizon, consistent with a lazy eight maneuver. He lost sight when he turned his own airplane and later saw the wreckage in a cornfield west of the sprayed field.
Personnel Information
The operator's chief pilot reported previously observing the accident pilot use aggressive flying techniques during an evaluation flight. He told the pilot that a hammerhead maneuver between spray passes was not acceptable and that turns should consist of three separate phases (field departure, procedure turn, and field reentry). The pilot agreed to review a training video, Turn Smart, on proper turning techniques.
Aircraft Information
The Air Tractor AT-502B flight manual (AFM) specifies spray passes at 130–140 mph and warns against abrupt pull-ups at the end of a pass to maintain airspeed during turns. The AFM states a maximum altitude loss of 220 ft during recovery from a wings-level aerodynamic stall at 8,000 lbs gross weight, but an aerodynamic stall in an uncoordinated turn results in a sharp pitch decrease and significant altitude loss. All aerobatic maneuvers, including spins, are prohibited.
Wreckage and Impact
The accident site was in a cornfield about 8.7 miles south-southeast of GGF. Onsite examination by an FAA inspector and an Air Tractor investigator revealed the airplane impacted terrain at an estimated 45° nose-down flightpath angle with no preceding debris path. The wreckage was upright with significant impact damage to the forward fuselage and leading edges of both wings, oriented east-northeast. Flight control continuity could not be established due to damage, but observed separations were consistent with impact. The flap actuator measured 2.875 inches, indicating flaps extended about 20° at impact. The engine and propeller were buried about 3 ft below ground; propeller damage was consistent with engine operation at impact.
Medical and Toxicological Findings
An autopsy determined the cause of death as blunt force trauma, manner accident, with no significant natural disease. Toxicological testing detected ethanol in cavity blood (0.058 g/dL), muscle tissue (0.128 g/dL), and brain tissue (0.036 g/dL). N-propanol, methanol, and n-butanol were detected at low levels in various specimens. The report notes that ethanol can be produced postmortem by microbes, and that the detected alcohols at low levels are not impairing.