WPR13LA233

The pilot reported that he was at a low altitude and in a turn for the next agricultural aerial application run when the airplane encountered its wake turbulence, and the inside wing stalled. He tried to apply rudder to recover, but the airplane inverted and pitched nosedown before it impacted terrain. The pilot reported no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation. The pilot awoke at 0445 on the day of the accident. He had been awake for over 15 hours and had flown 71 application loads during 12 of those hours at the time of the accident. Due to the early wake time and high work load, the pilot was most likely fatigued at the time of the accident.

On May 15, 2013, about 1900 Pacific daylight time, a Schweizer Aircraft Corporation G-164D, N83110, collided with terrain near Butte City, California. Jones Flying Service, Inc., was operating the airplane under the provisions of 14 Code of Federal Regulations (CFR) Part 137. The commercial pilot sustained minor injuries; the airplane sustained substantial damage to the fuselage and wings from impact forces. The local aerial application flight departed Butte City at 1855. Visual meteorological (VMC) conditions prevailed, and no flight plan had been filed. The pilot reported that he was in a turn for the next application run. The airplane encountered its wake turbulence, and the inside wing stalled. It went inverted and pitched nose down. The pilot tried to correct with rudder application, but due to the low altitude he could not recover before the airplane contacted terrain. It came to rest in a rice field. The pilot was able to extricate himself, and walk to a road. The pilot stated that there were no mechanical malfunctions or failures with the airplane that would have precluded normal operation. The pilot had flown 12 hours and 71 loads on the day of the accident. He was awake at 0445 the morning of the accident, and characterized the day of flying as dawn to dusk; very busy with multiple loads.