A helicopter crash in a remote Southland location has prompted the Transport Accident Investigation Commission (TAIC) to make recommendations on refuelling practices.
It followed actions taken by the pilot when refuelling that enabled an opportunity for the fuel to be contaminated, which TAIC said may have contributed to the helicopter losing power.
The report by the TAIC said the helicopter in question was operated by Heliops Southland Ltd and was conducting agricultural spraying in 2016 around the Hokonui Hills.
"The pilot reported hearing the low rotor RPM warning horn just as he had turned the helicopter to fly downwind.
"The helicopter crashed into a paddock at relatively low speed."
The pilot walked away with minor injuries but the aircraft was significantly damaged.
"Contaminated fuel very likely caused the power loss, and the operator's refuelling procedures left opportunities for contamination to occur," the report read.
TAIC made a recommendation to the Director of Civil Aviation to provide the industry with more educational material and guidance on mitigating the risk of contaminated fuel when operating at remote sites.
"The commission recommended that the Director of Civil Aviation review and enhance all CAA-published guidance information to better inform the industry on hazards associated with remote refuelling."
TAIC also made a recommendation to the president of Aviation New Zealand to promote the lessons learned from the accident to its members.
The key lessons to be learned from the incident was that refuelling aircrafts at remote locations increased the risk of fuel contamination.
"Operators should take all precautions to prevent any debris entering the fuel supply chain, from the initial fuel supplier to the aircraft fuel tank."
It also said aircraft fuel-filtering systems were an important defence against contaminated fuel causing an accident.
"Where available, operators should consider fitting additional airframe filters to aircraft being operated and refuelled at remote locations."