A light plane that crashed yesterday killing three people just north of the South Australian town of Mount Gambier, was a charity flight on its way to Adelaide.

The victims were 78-year-old Adelaide Hills man, Grant Gilbert, who was flying the aircraft, and a 16-year-old girl and her 43-year-old mother — both from Mount Gambier, in South Australia’s south-east.

Four Australian Transport Safety Bureau (ATSB) investigators will spend the day at the scene where the Angel Flight crashed.

The plane, a TB10 Tobago, took off from the nearby airport just after 10:00am yesterday and the first report of the crash at Suttontown about five kilometres away came at 10:24am.

“While on site, the team will be examining the site and wreckage, gathering any recorded data and interviewing any witnesses,” the ATSB said in a statement.

Police said conditions were foggy and wet in the area at the time of the crash.

Angel Flight is a charity which coordinates non-emergency flights to help country people reach medical treatment and appointments. The service has volunteer pilots and drivers.

Mr Gilbert became the license holder and operator of the single-engine plane in 2014 and often flew it between Adelaide, Mount Gambier and Port Lincoln.

It’s the second serious plane crash in South Australia in the past two months with a Cessna Conquest operated by charter company Rossair crashing near Renmark in May, also killing all three on board.