Accident Overview
Following maintenance, a pilot conducted a test flight in a helicopter. The takeoff was made with the left passenger door unlatched. When this was pointed out to the pilot by radio, he began a precautionary approach to close the door.
In-flight Incident
During the approach, the pilot felt and heard a bang, followed by a vibration and rattling noise. These sensations subsided, and the pilot assessed a loss of tail rotor control. He then executed a forced landing.
Forced Landing and Impact
As the helicopter landed, it rolled onto its left side. The main rotor blades and rotor head separated from the helicopter. The main rotor blades and tail rotor struck the tail boom during the event.
Post-accident Observations
At the time of the flight, a jacket with red and black stenciled letters on the back was lying on the passenger seat. The jacket was not found after the accident.
Examination of the helicopter revealed a torsional fracture of the number 4 tail rotor drive shaft section and a bend in the number 5 section. The tail rotor blades exhibited red paint transfer; one blade had a dent in the leading edge and a bend near the blade root. Analysis of the paint transfer showed it did not originate from the jacket lettering. Parts of the helicopter were painted red, and the red portion of the tail boom displayed paint transfer and slap marks. The tail rotor blades did not show rotational impact damage.