A charity flight has crashed near Horsham in Victoria Australia, killing a 15 year old girl, volunteer pilot and has left the girl's 43 year old mother in a critical condition in hospital.

The plane operated by the charity organisation Angel Flight left Essendon Airport near Melbourne en-route to Nhill in the state's west where it crashed in a paddock near the town of Wallup in heavy rain.

The volunteer pilot with some 800 hours of flying experience had flown around 25 missions for Angel Flight.

A spokesperson advised that the 15 year old girl was receiving medical treatment and this was her 24th flight back and forth to Essendon.

It took emergency crews about an hour-and-a-half to find the wreck, after a local reported seeing a low-flying plane and heard a loud bang. The Australian Transport Safety Bureau is investigating the incident.