Aircraft debris found in waters where pilot crashed

Aircraft debris has been found in waters off remote islands in Australia's north where a search is underway for a missing pilot after his plane crashed into the sea.

An Air Frontier twin-engined Beechcraft Baron aircraft went missing after taking off from Gove airport at Nhulunbuy on the Northern Territory coast with only the pilot aboard.

The air charter company's plane was due to land at the remote Indigenous community of Numbulwar at 11.50am on Tuesday but never arrived.

A search led by Northern Territory Police began after a witness on a vessel reported seeing the plane crash into the sea near Isle Woodah.

The search on Thursday involves police and Aboriginal ranger vessels, a helicopter and a police plane.

Police divers have also been deployed to conduct searches of the sea floor in the vicinity of the crash site.

Search Mission Co-ordinator, Acting Sergeant Nathan Conelius, on Thursday told ABC Radio that in "a little bit of good news" aircraft debris had been found in the search area on Wednesday.

"That's helped refine our search planning so we are more hopeful today of finding something else."

There were strong sea currents in the area that could move debris, he said.

Police were in touch with the pilot's family who were being regularly updated on the search.

Air Frontier CEO Kylie Hunt said the company was "deeply saddened" by the accident and her thoughts were with the pilot and their family.

As a precautionary measure, the company has grounded all five of its Beechcraft Baron aircraft pending advice from authorities.

The Australian Transport Safety Bureau has initiated a crash investigation.