Casualties unknown

1993-05-14: Air Tractor AT-401 (N4503U) — Olson Air Service, Inc. — Oconto, NE

Oconto, NE, US

On May 14, 1993, an Air Tractor AT-401 (registration N4503U) operated by Olson Air Service, Inc. was involved in an aviation accident near Oconto, NE. Investigators recorded the probable cause as: The pilot's encounter with a microburst during agricultural spraying operations, which resulted in a loss of control and impact with the terrain. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.

Sourcesthe U.S. National Transportation Safety Board (NTSB) historical archivePrimary reportUpdated 1781061362Data APIEditorial standards

An agricultural airplane descended from 400 feet and impacted terrain after the pilot encountered a suspected microburst during a spray operation near Broken Bow Airport.

What happened

The pilot was conducting an agricultural spraying operation, flying over a field in preparation for a run when a rain shower developed in the area. According to the pilot's statement, the aircraft encountered a microburst during this weather event. In an attempt to maintain altitude and counteract the downdraft, the pilot dumped the chemical load carried by the airplane.

Despite these efforts, the aircraft continued to descend from an approximate altitude of 400 feet before impacting the terrain. A surface weather report issued 25 minutes after the accident from Broken Bow Airport, located 19 miles north-northeast of the site, indicated virga conditions south-southwest of the airport.

The investigation

The investigation relied primarily on the pilot's statement regarding the encounter with a microburst and the subsequent dumping of the chemical load. No mechanical examination details were provided in the source text.

Findings

Contributing factors included the encounter with a microburst during agricultural operations and the resulting loss of altitude. The weather conditions, specifically virga reported nearby shortly after the event, supported the presence of precipitation-induced downdrafts.

Probable cause

The pilot's encounter with a microburst during agricultural spraying operations, which resulted in a loss of control and impact with the terrain.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001211X12353. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.