Fatal training flight spiralled into turf

A mayday call was made but not completed by the pilot of a training flight which spiralled from the sky and crashed nose-first into a turf farm south of Brisbane, killing two men aboard the plane.

The instructor and his student died at the scene, with local farm manager Darryl Pearce saying he rushed to help but "it was pretty obvious we could do nothing".

The single-engine Diamond DA-40 had taken off from Archerfield and was in the air for about 40 minutes before a distress call was sent and it crashed into the Allenview farm, near Beaudesert, on Tuesday morning.

Mr Pearce said two of his workers saw the four-seat aircraft spiralling towards the ground.

"Got down there, luckily the plane wasn't on fire but getting close to it (I) ran over to see what we could do for the people," he told ABC radio.

"It landed upright."

Photos from the scene show the broken plane lying on a large expanse of grass but it is too early to speculate about what caused the fatal crash, the Australian Transport Safety Bureau and the Civil Aviation Safety Authority say.

The men are yet to be formally identified.

ATSB investigators from Brisbane and Canberra will spend days examining the site and trying to retrieve flight data from recording devices attached to avionics.

It is the second fatal aircraft crash in southern Queensland in a week.

Experienced instructor Jeremy Thompson and his 60-year-old student Norbert Gross died when their glider nosedived 15 metres and crashed into a field near the runway at the Darling Downs Soaring Club last Tuesday.

Following investigations into the Allenview crash the ATSB will prepare a report, which is expected to take months to complete.