Poor helicopter design causes a tragic accident.
A coroner has recommended black boxes become mandatory for all helicopters
They also called for a ban on Robinson helicopter flights during turbulence and speed restrictions
More research is needed to understand mast-bumping and rotor blade divergence in Robinsons
If Stephen Combe and James Patterson-Gardner were in any helicopter other than a Robinson they probably would not have died, a coroner has found.
Coroner Alexandra Cunninghame held an inquiry into the deaths of Combe, 42, and Patterson-Gardner, 18, in Queenstown, last year.
Patterson-Gardner was a student pilot and was flying the Robinson helicopter ZK-IPY. He was under Combe’s supervision in the Lochy Valley, near Queenstown.
The helicopter belonged to Over The Top, a well-known Queenstown company owned by Patterson-Gardner’s mother that employed Combe.
In findings released on Monday ,the coroner noted the weather was good on the day of the crash. However it was likely the pair encountered an abrupt wind change or gust.
That caused a “main rotor blade divergence sequence”, sometimes known as mast bumping. This is when the blades of the helicopter struck the cabin, breaking it up in mid-air.
It happened in a matter of seconds and both pilots were killed instantly when they crashed.
“In any other type of helicopter, the accident would not have occurred in these circumstances,”
Coroner Alexandra Cunninghame
The risk was increased by the airspeed of 102 knots, which was within the recommended limits, and the fact a student pilot was at the controls, she said.
However, the design of the Robinson rotor head made the R44 and the R22 particularly vulnerable to gusts, turbulence, and wind direction changes, even at relatively conservative speeds.
Poor Helicopter Design Causes Tragic Accident
More research was needed to better understand what caused main rotor blade divergence in Robinson helicopters, the coroner said.
Until then, the helicopters should not be flown at speeds over 70 KIAS (knots of indicated airspeed). Particularly in areas where moderate to severe turbulence was likely, she said.
Robinson helicopters were particularly vulnerable in New Zealand as many areas were mountainous and turbulence was more likely.
The coroner also called for:
- Mandatory data recording systems, or black boxes, in all helicopters
- For the Civil Aviation Authority (CAA) to prohibit Robinson helicopters from being flown in moderate or severe turbulence, and
- To restrict the speed of the helicopters in mountainous areas.
