What aircraft was involved and where did it happen?

The accident on 1987-07-23 involved a Hiller 12E, registration N67139, operated by Tri Rotor Spray, at Ulysess, KS.

Main Rotor Hub Failure During Helicopter Aerial Application Flight (N67139)

On July 23, 1987, a Hiller 12E (registration N67139) operated by Tri Rotor Spray was involved in an aviation accident near Ulysess, KS. Investigators recorded the probable cause as: The pilot stated that the linkage pin that goes through the mast and pitch change mechanism was not aligned causing the failure. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.

A helicopter conducting aerial application experienced a main rotor hub failure shortly after takeoff. The pilot reported a misaligned linkage pin caused the failure, leading to an uncontrolled descent and substantial damage.

Incident Overview

During an aerial application operation, a helicopter sustained a main rotor system hub failure. The pilot in command (PIC) reported that the complete rotor head, blades, and paddles had just been reinstalled. After a flight of less than one mile, the failure occurred, rendering the PIC unable to control the aircraft. An uncontrolled descent followed, and the helicopter struck the terrain.

Damage and Injuries

The helicopter was substantially damaged. The PIC suffered minor injuries.

Pilot Statement

The PIC stated that the linkage pin that goes through the mast and pitch change mechanism was not aligned, causing the failure.

Conclusion

The investigation determined that the main rotor hub failure resulted from a misaligned linkage pin. No other causal factors were identified.

Probable cause

The pilot stated that the linkage pin that goes through the mast and pitch change mechanism was not aligned causing the failure.

1987-07-23: Hiller 12E (N67139) — Tri Rotor Spray — Ulysess, KS