What happened
The aircraft was engaged in an aerial application mission when the pilot decided to abort the operation due to deteriorating weather conditions. According to the pilot's account, he had completed two spray passes over the target field before noticing a flagman and several farmers signaling him to stop. The ground personnel were waving him off because of an approaching thunderstorm.
Upon deciding to leave the area, the pilot executed a standard right turn toward the north. During this maneuver, the aircraft encountered wind shear. This sudden change in wind conditions forced the right wing down almost into an inverted position before the aircraft made contact with the ground. Witnesses observed the plane circling briefly to confirm the signal to depart, after which it began a right turn and lost altitude rapidly. The aircraft struck the ground wing first.
Weather data from Yuma, Arizona, recorded at 1055 hours included remarks noting cumulonimbus clouds moving from southeast to northwest through the northwest quadrant of the area.