Don Kernot, 69, and a 15-year-old from Nhill were killed instantly when the light plane they were in plunged into a paddock near Wallup, about 40 kilometres north of Horsham in Western Victoria.

The teen's mother, 43, suffered head, chest and rib injuries and was flown to the Royal Melbourne Hospital where she is in a critical condition.

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The trip was part of an Angel Flight journey from Melbourne to the teenager's hometown of Nhill.

Mr Kernot regularly donated his time and Piper Cherokee 180 aircraft to Angel Flight, a charity that co-ordinates non-emergency flights to help country people access medical services.

Angel Flight CEO Bill Bristow told The Age that the girl and her mother, from Nhill, about 60 kilometres west of Wallup, had made 20 trips with Angel Flight over the past five years for the girl to receive treatment for an undisclosed medical condition at a Melbourne Hospital.

He said the flight took off at Essendon Airport as scheduled yesterday afternoon, but the girl’s father phoned Angel Flight shortly about 6.30pm to say the flight had not arrived in Wallup.

The Australian Transport Safety Bureau has been investigating the scene in the morning.