Brothers Confirmed Dead In Light Plane Crash

Queensland brothers Robert and Owen Dull died after their single-engine plane crashed on Sunday.

The experienced aviators from Toowoomba and Roadvale died when the aircraft came down between Casino in northern NSW and Boonah in Queensland.

A statement from the family said that Robert, 68, and Owen, 61, were both "passionate about aviation".

"Robert is survived by his wife, three adult sons, their spouses and four grandchildren. Owen is survived by his wife," the statement said.

"We would like to thank all of those involved in the search and recovery efforts for Robert and Owen in difficult conditions."

The family said that Robert had built the plane as a "labour of love" and "it had met all regulatory requirements".

In October last year, the plane was awarded the 'John Liddell Award, Best Hybrid Experimental Amateur Built Aircraft 2019' by the Sport Aircraft Association.

The single-engine aircraft left Casino Airport in NSW about 2pm on Sunday, headed for Boonah.

Following a coordinated search, a Westpac Rescue Helicopter found the crash site in rugged terrain in the Koreelah National Park on Monday morning.

NSW police rescue and SES volunteers scoured the area on foot, with officers arriving at the crash site about 3pm, later confirming the two men had died.

Homebuilders need to have their kit planes checked by an engineer and complete flight tests away from populated areas before they can be flown regularly, Civil Aviation Safety Authority spokesman Peter Gibson told AAP.

"It's a basic plane ... but it is regulated," Gibson said.

Any investigation into the crash will be conducted by the Australian Transport Safety Bureau.

It's likely the bureau will examine if weather conditions or poor visibility played a part in the crash.