Helicopter model faulted in crash

Louisa Patterson and her son James Patterson-Gardner, who died in the crash along with Stephen...
Louisa Patterson and her son James Patterson-Gardner, who died in the crash along with Stephen Combe. PHOTO: SUPPLIED
The crash of a Robinson helicopter near Queenstown that killed two men would not have occurred in any other type of helicopter, a coroner has found.

The Robinson R44 broke up in midair during a training flight over the Lochy River valley on February 19, 2015, causing the deaths of 18-year-old student pilot James Patterson-Gardner, of Queenstown, and experienced pilot Stephen Combe (42), of Wanaka.

In her findings released yesterday, coroner Alexandra Cunninghame said the aircraft experienced "main rotor blade divergence", in which the rotor blade diverged from its normal plane and swung through the cabin, breaking up the helicopter and killing the two men instantly.

"On the balance of probabilities", the helicopter encountered an abrupt change in wind flow or a gust, exposing it to the risk of main rotor blade divergence.

Robinson helicopters’ rotor head design made them susceptible to turbulence.

"In any other type of helicopter, the accident would not have occurred in these circumstances."

The coroner recommended Robinsons not be flown in moderate or severe turbulence, and should not exceed 70 knots while flying in mountainous areas.

She noted that flight data recording systems, or "black boxes", were not required in New Zealand for aircraft carrying up to 10 passengers.

However, she recommended a different type of device, a helicopter cockpit video recorder system, be made mandatory for all helicopters.

She urged the helicopter community to not wait for regulatory change, but install the systems "as soon as reasonably practicable".

At the time of the accident, the aircraft was being flown by Mr Patterson-Gardner, son of Louisa Patterson, chief executive of Queenstown helicopter company Over the Top.

Ms Patterson could not be reached for comment.

The coroner said the evidence presented at the inquest, held in the resort town in June last year, indicated the aircraft’s last known ground speed of 102 knots was "too fast to be safe" in the event of turbulence.

However, the pair could not be criticised for travelling at that speed, because it was within the applicable recommendations and safety advice in force at the time.

There was no evidence of mechanical fault or pilot error, although the risk was increased by a student pilot being at the controls.

There had been 19 deaths in Robinson helicopters in New Zealand attributed to main rotor blade divergence since 2000, and more than 50% of fatal helicopter accidents in the country since 2000 had been in Robinsons, she said.

"Given that approximately 25% of New Zealand’s fleet are Robinsons, they appear to be over-represented in accident statistics."

More research was needed into the Robinson rotor head design.

The United States company, which did not take part in the inquest, was aware of the issues with its aircraft, but had never made any significant changes to the design.

"Instead, [the company] prefers to issue safety notices and to provide pilot education, thus bringing the helicopter community’s attention to the limitations of its machines."

In 2016, the Transport Accident Investigation Commission put Robinson helicopters on a safety watchlist.

That prompted several government agencies, councils and companies, including the Department of Conservation and the Otago Regional Council, to ban staff or contractors from flying in Robinsons.

guy.williams@odt.co.nz

 

 

 

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