Schweizer Aircraft Corp G-164D N83110 accident near Butte City, California

Probable cause

The pilot's failure to maintain airplane control after an encounter with wake turbulence while maneuvering at low altitude. Contributing to the accident was the pilot’s fatigue due to extended hours of wakefulness and high workload.

NTSB analysis

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.

Text from the NTSB. Open the NTSB docket for WPR13LA233 for the full record.