Primary finding
Probable cause
The pilot's failure to maintain airspeed and his exceedance of the airplane's critical angle of attack, which resulted in an aerodynamic stall while maneuvering.
Investigator assessment
Analysis narrative
The commercial pilot stated that during a routine aerial application, he circled the airplane around the field to be sprayed to locate obstacles. He sprayed the field from north to south and made passes from east to west. During the third pass, when the airplane exited the field to the west to return for an eastward pass, he felt the airplane shake at the apex of the turn. He said that he corrected for the shake/stall, and the shaking quit for a moment. He then felt the right wing "take a hard dip." The airplane entered a right roll, impacted the ground, and was destroyed. The pilot reported that there was no mechanical malfunction or failure of the airplane. It is likely that, while maneuvering, the pilot failed to maintain the proper airspeed and exceeded the airplane's critical angle of attack, which led to an aerodynamic stall.
Source record
Factual narrative
On June 6, 2016, at 1316 central daylight time, an Air Tractor Inc. AT-502, N10325, impacted terrain during an aerial application of a field near Ropesville, Texas. The airplane was destroyed. The pilot received serious injuries. The airplane was operated by T-C Aerial LLC under the provisions of 14 Code of Federal Regulations Part 137 as an aerial application flight that was not operating on a flight plan. Visual meteorological conditions prevailed at the time of the accident. The pilot stated that during a "routine" aerial application, he circled the field to be sprayed to locate obstacles. He sprayed the field from north to south and made passes from east to west. During the third pass when the airplane exited the field to west to return for an eastward pass, he felt the airplane shake at the apex of the turn. He said that he corrected for the shake/stall, and the shaking quit for a moment. He then felt the right wing "take a hard dip." The airplane entered a right roll and impacted the ground. The pilot stated that there was no mechanical malfunction/failure of the airplane.