A father and son have died after their light plane crashed in rural South Australia.

Emergency crews were called to Merriton, 170 kilometres north of Adelaide, about 4.10pm on Sunday after reports a light plane had struck power lines and crashed in a field.

The men were pulled out of the wreckage by witnesses.

The pilot, identified by The Advertiser as Ben Mumford, suffered serious injuries. He was taken to a local hospital before being flown to the Royal Adelaide Hospital.

The 50-year-old Redhill man died overnight.

His 24-year-old son, Charlie Mumford, died at the scene.

The crash sparked a grass fire that was put out by CFS and local farm units.

Major crash officers attended the scene on Sunday. Investigators from the Australian Transport Safety Bureau were to join them on Monday to try to piece together what caused the crash.

“The ATSB asks anyone who may have witnessed the accident, or may have video footage of the aircraft in any phase of its flight, to make contact,” the bureau said.

– AAP