Bell UH-1H N900VF accident near Woodlawn, Illinois

Probable cause

The separation of the tail boom from the fuselage for reasons that could not be determined.

NTSB analysis

The pilot reported that the helicopter exhibited a “sudden bounce/shake that became extremely violent.” He immediately began a descent for landing in a corn field. About 50 feet above ground level, the helicopter began an uncommanded 180° turn and landed upright in the field.

The tail boom separated and was located in the corn field near the fuselage. The fuselage and main rotor blades were damaged, and the main rotor transmission was dislocated from the mounts, consistent with the forced landing.

The operator reported that there was no mechanical malfunction or failure associated with the helicopter, and that the engine was still running after impact. However, because the operator did not make the helicopter available for a postaccident examination, the reason for the violent bouncing/shaking and subsequent tail boom separation could not be determined.

Text from the NTSB. Open the NTSB docket for CEN23LA295 for the full record.