NTSB Identification: CHI01LA151.
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Accident occurred Sunday, June 03, 2001 in Mount Vernon, SD
Probable Cause Approval Date: 02/20/2002
Aircraft: Air Tractor AT-402B, registration: N484WB
Injuries: 1 Fatal.

NTSB investigators may have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

An Air Tractor 201 impacted the terrain 4.5 miles northeast of Mount Vernon, South Dakota. A witness said he was outside in his farmyard working when he heard an airplane working east of his farm. The witness said he saw the airplane a couple of times as it was making turns. The witness said he could hear the airplane's engine. He then heard a loud crash noise and didn't hear the airplane's engine anymore. An examination of the airplane revealed no anomalies. FAA toxicology testing of specimens from the pilot showed trace levels of QUININE in blood. Quinine is found in tonic water and is used to treat malaria. It is also commonly used to reduce the frequency of nocturnal leg cramps - a condition which may cause painful leg muscle spasm at night, and was available over-the-counter for this purpose until 1995. The side effects of quinine can include disturbances of vision, hearing, and balance. According to the pilot's brother, tonic water was the pilot's favorite beverage. The night prior to the accident, the pilot was observed drinking tonic water with his dinner.


The National Transportation Safety Board determines the probable cause(s) of this accident to be:

the pilot not maintaining aircraft control while maneuvering close to the ground.

Full narrative available

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