Information verified through data from accident investigation authorities
Narrative: During a test flight, the helicopter developed a low frequency vibration with a partial loss of control. The crew managed to manoeuvre it to a position where a landing was attempted but the machine rolled over as it was about to land. The non-flying crew member received a very minor injury during the evacuation. Investigation found that the single link scissor pitch rod end had failed on the threaded portion. The part had not been over-torqued and had failed progressively over a short time. As a result of this incident the designers are now going to introduce a double scissor link for both the rotating and non-rotating mechanisms.