Casualties unknown

1986-04-07: Hiller UH-12B (N5307V) — Fall River, KS

Fall River, KS, US

On April 7, 1986, a Hiller UH-12B (registration N5307V) was involved in an aviation accident near Fall River, KS. Investigators recorded the probable cause as: The pilot's failure to maintain adequate airspeed and main rotor RPM during the descent, which resulted in a loss of control and impact with trees. 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

A helicopter descended into a plowed field and struck tree tops before nosing over. The pilot admitted to reducing airspeed and rotor RPM too much, leaving insufficient time to recover from the situation.

What happened

The aircraft was operating in close proximity to a plowed field when it encountered vegetation along the perimeter. According to the pilot's account, the intention was to execute a landing within the cleared area. During the descent phase, the pilot allowed both the airspeed and the main rotor revolutions per minute (RPM) to decrease significantly.

As the aircraft approached the ground, the pilot observed trees located at the edge of the field. By this point, the loss of energy in the system had become critical. The pilot stated that it was too late to recover from the deteriorating flight condition. The helicopter subsequently flew through the tops of these trees and impacted the plowed field almost vertically.

Upon impact, the aircraft nosed over and came to rest in an inverted position. No further details regarding injuries or specific aircraft registration were provided in the source text.

The investigation

The investigation relied primarily on the pilot's statement regarding the sequence of events. The mechanical condition of the helicopter was not detailed in the available records, but the flight dynamics described indicate a loss of rotor energy during the final approach.

Probable cause

The pilot's failure to maintain adequate airspeed and main rotor RPM during the descent, which resulted in a loss of control and impact with trees.

Investigation report by the U.S. National Transportation Safety Board (NTSB) historical archive. Original record: https://carol.ntsb.gov/event/20001213X33372. This page is a structured re-presentation; facts and quotes are in the National Transportation Safety Board (NTSB), United States.