Two men killed as light plane explodes in 'fireball'

Two men are dead after a light plane crashed into a paddock in Queensland's Darling Downs, igniting a "fireball" the property owner and emergency services couldn't put out in time.

The twin turboprop Reims-Cessna F406 aircraft came down near Oakey, north-west of Toowoomba, about 3pm today.

It was heading from Warwick to Brisbane before it was diverted to Oakey.

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Flight-tracking data show the plane circled twice above the tiny town of Brymaroo before heading straight towards Oakey Airport.

But the pilot and co-pilot didn't make it, instead coming down in a paddock next to Oakey-Cooyar Road, just a few kilometres short of their destination.

Acting Senior Sergeant Matt Forbes said the plane created a "very large fireball" and confirmed the occupants had died on impact.

"The male occupant of the property owner was home at the time, heard a loud explosion, and was able to contact emergency service," Forbes said.

Locals rushed to help but it was too late.

"Couldn't get to it mate, exploded before I got there," one man can be heard saying in a video posted to social media.

A crime scene has been established and the Australian Transport Safety Bureau will be conducting an investigation with police and other agencies.

Forbes said the scene was expected to remain active for "a number of days" and air crash investigators would fly up from Canberra tomorrow.

He said the plane, which had already carried out two flights between Emerald, Brisbane and Warwick earlier in the day, was engaged in "routine flight".