Helicopter that crashed in north Canterbury a 'particularly safe aircraft' - expert

An aviation expert says the helicopter that crashed in north Canterbury on Tuesday has a good safety record.

Two people - Andrew Hamish Davidson, 60, and his wife Lin Chen, 39 - were killed in the crash that occurred about 60km north of Kaikōura. Three other people, two reportedly their children, were seriously injured and airlifted to Wellington Hospital.

The group was coming in to land at a popular seaside restaurant near the Kekerengu River mouth.

Aviation expert Bill MacGregor says the model of the helicopter the group was flying in is a "safe aircraft".

"Modern aircraft, modern helicopters, turbine-powered, they've normally got plenty of power, they've got a good rotor system," he says. "These are particularly safe aircraft, they don't have a history of crashes."

Crash witness Ian Mehrtens was among the first people on the scene.

"It's just the noise of the children screaming for help, sort of thing, and in pain. It wasn't nice," he says.

Neighbours of the family killed and injured say they regularly saw them take the helicopter out at weekends.

"It was a pastime they enjoyed doing together," one told Newshub.

Medbury School, where the couple's son is a student, released a statement on Wednesday confirming the tragic news.

"It is with a heavy heart that I write to inform the Medbury community that the family named in yesterday's crash is one of our own."

As they come to terms with the grief, the Transport Accident Investigation Commission has launched an inquiry to piece together the family's final moments.

Chief investigator of incidents Harald Hendel says the investigators' work will include inspecting the wreckage, mapping the site, talking to witnesses, and looking at recorded data from the helicopter's electronics.