Probe into north Qld ultralight tragedies

Investigators are attempting to piece together what caused two ultralight planes to crash in north Queensland, killing two experienced pilots.

The bodies of Robin Friend, 72, and Errol Young, 68, were found in wreckage about 7km from Donnington Airpark, just south of Townsville, on Wednesday.

The friends were reported missing on Tuesday night after they failed to return to the airfield from what was supposed to be a short sightseeing trip.

Recreational Aviation Australia CEO Michael Linke says the cause of the crash is still unknown and two investigators remain at the scene.

"We haven't made any initial findings at this stage but we've ruled out the powerlines as being hit, but we don't whether they were a contributing factor," he told AAP.

"We know that on inspection of the aircraft, there doesn't appear to be any mechanical or airframe problems with the aircraft.

"But we can't make any speculations about what did happen."

The probe will look at the mechanics and history of the aircraft, the pilots' experience, as well as the weather and surrounding area.

Investigators will likely leave the scene later on Thursday but it could take up to a few weeks for a report to be finalised and handed to the coroner.

Airpark owner Ray Smith, who had known both victims for several years, has said the men were both highly experienced pilots.

Mr Friend, who recently moved from Townsville to the Atherton Tablelands, inland from Cairns, was a helicopter pilot in the Vietnam War and had more than 30,000 flying hours under his belt.

Mr Young, from Townsville, was a keen flyer who spent most weekends at the airpark.

Mr Smith said the men were good friends and had flown together on a number of occasions.

"It's a bloody traumatic experience," he told AAP on Wednesday.

"This is very bad news; I think it's about the worst I've ever had."