- A coroner has recommended that black boxes become mandatory for all helicopters
- They also called for a ban on Robinson helicopter flights during turbulence and speed restrictions
- Further research is needed to understand mast bumping and rotor blade divergence in Robinsons
If Stephen Combe and James Patterson Gardner were in a helicopter other than a Robinson, they probably wouldn’t have died, a coroner has found.
Coroner Alexandra Cunninghame led an inquest into the deaths of Combe, 42, and Patterson Gardner, 18, in Queenstown last year.
Patterson-Gardner was a student pilot and flew the Robinson ZK-IPY helicopter 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 who employed Combe.
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In findings released on Monday, the coroner noted that the weather was good on the day of the crash, but it was likely the pair had encountered a sudden wind shift or gust.
This caused a “main rotor blade divergence sequence”, sometimes referred to as mast knock, where the helicopter blades struck the cabin, shattering it in the air.
It happened within seconds and both pilots were killed instantly when they crashed.
“In any other type of helicopter, the accident would not have occurred under these circumstances,” concluded the coroner.
The risk was increased by the speed of 102 knots, which was within recommended limits, and the fact that a student pilot was at the controls, she said.
However, the Robinson rotorhead design made the R44 and R22 particularly vulnerable to gusts, turbulence, and changes in wind direction, even at relatively conservative speeds.
Further research was needed to better understand what caused main rotor blade divergence in Robinson helicopters, the coroner said.
Until then, helicopters should not fly at speeds above 70 KIAS (knots indicated airspeed) in areas where moderate to severe turbulence was likely, she said.
Robinson helicopters were particularly vulnerable in New Zealand because many areas were mountainous and turbulence was more likely.
The coroner also called for mandatory data-logging systems, or black boxes, in all helicopters, and for the Civil Aviation Authority (CAA) to prohibit Robinson helicopters from flying in moderate or severe turbulence and limits the speed of helicopters in mountainous areas. .
Following its investigation into the 2015 crash, the Transportation Accident Investigation Commission (TAIC) recommended the use of in-flight video and data recorders in these aircraft.
At the time, the Department of Transport and the CAA said the recommendation was “premature”, but the Director of Civil Aviation asked for an assessment of the safety and cost benefits of the recording devices.
This week, CAA director Keith Manch said the organization was working on the coroner’s findings, which “will take time”.
“At this stage of our analysis, we are unable to comment on how they will be handled,” he said.
Robinsons are very popular in New Zealand largely because of their cost, which is around $500,000 for a four-seat R44, less than half the price of an equivalent Bell helicopter.
Investigator Tom McCready described them as “the scooter of helicopters…there for the masses to fly relatively cheaply”.
CAA data showed that in July 2021, 223 of the 886 helicopters registered in this country were Robinsons, or about 25% of the fleet.
From 2000 to July 2021, the Robinsons were involved in 52% of fatal helicopter crashes and 42% of all helicopter crashes.
There have been 19 fatalities in Robinson helicopters in New Zealand which TAIC has attributed to the rotor blade divergence / mast knocking issue.
Robinson Helicopter Company (RHC) is based in the United States and chose not to be represented at the inquest, although it made belated submissions afterwards.
The company was aware of the problems with its helicopters, but no significant changes have been made to the design since the first was sold in 1979, the coroner said.
“Instead, RHC prefers to issue Safety Advisories 23 and provide pilot training, drawing the attention of the helicopter community to the limitations of its machines.”
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As two more people die in a Robinson helicopter crash, a US attorney representing crash victims and families calls the helicopter “unsafe and unfit to fly”. (Video first published in November 2016).
There was no evidence that Patterson Gardner and Combe were flying outside the recommended limits when they crashed, she said.
There was no evidence of mechanical failure, or pilot error, she said.
It was widely agreed that further studies of the Robinson rotorhead design were needed, she said.
RHC said it had recently engaged an engineering company to undertake further studies on the six-seat R66.
During the coroner’s inquest, Patterson Gardner’s mother said it had become her mandate to improve aviation safety since the crash and that she had developed a black box known as the Eye in the Sky for use in helicopters.
“[ZK-IPY] was the only Robinson in my fleet. I will never allow my pilots to fly in a Robinson helicopter again,” Louisa Patterson said.
She declined to comment on the coroner’s findings.
In 2016, TAIC added Robinson helicopters to its watch list, and government departments such as the Department of Conservation – New Zealand’s biggest user of helicopters – stopped using them.