Harrogate relevance of the 3 aircraft is as per this info released in Australian Press from PNG - it seems 3 left, 1 landed, 1 turned back:
Nine Aussies on missing PNG plane bound for Kokoda
August 11, 2009 06:22pm
.UPDATE: NINE Australians are aboard a missing Papua New Guinea plane, the Department of Foreign Affairs and Trade says.
A DFAT spokeswoman said Airlines PNG had advised that 13 people were on board the plane that went missing on Tuesday en route to the Kokoda Track.
"Nine of the passengers are known to be Australians," she said.
"Consular staff are contacting families of the Australian passengers to offer consular assistance."
The Twin Otter, twin engine, plane left the capital Port Moresby on Tuesday morning at 9.30am (local time) but had failed to return Tuesday afternoon.
Locator map: Plane missing in PNG
It was last heard from as it approached Kokoda.
Authorities hold fears for the missing 13 people on board, including nine Australians heading to the Kokoda Track.
Ori Kennia, former Kokoda mayor, told AAP that PNG authorities began ringing him at lunchtime asking if he had seen anything unusual.
"They rang and I told them, the plane they were talking about, I didn't see it come in," he said.
"There is a plane now circling around searching for it."
The plane had been flying through the Owen Stanley ranges that are famous for its mountainous and rugged terrain.
"The weather up here is really bad, completely overcast," Kennia said.
The charter was scheduled to arrive at the small village of Efogi at 9.55am (local time), before being due at Kokoda by 10.15am, then back at Port Moresby by 11am.
PNG's Civil Aviation Authority are expected to make a statement shortly.
An Airlines PNG plane has begun a search and rescue mission.
Airlines PNG in a written statement said intensive search efforts had begun in the Owen Stanley Ranges north of Port Moresby for one of its planes.
``The airline advises that there are 11 passengers and two crew members aboard the missing plane,'' a spokesperson said.
``The last communication from the missing aircraft was received as it approached Kokoda and an extensive search and rescue mission was activated after it failed to land.''
A major Australian Kokoda adventure company says none of its clients are believed to be on board the missing Papua New Guinea plane.
Adventure Kokoda chief executive Charlie Lynn says all his clients are accounted for after an Airlines PNG aircraft failed to arrive at its destination on Tuesday.
There have been fears eight Australians from Adventure Kokoda were on the plane.
"I've been told that there are no Adventure Kokoda trekkers (on the plane)," he said.
"One of our planes did land at Kokoda today and there are 14 of our trekkers in Kokoda.
"A second plane couldn't get in because of weather. Those 12 trekkers have returned and they're safely in Port Moresby.
"There is an Airlines PNG plane missing. They have helicopters out there searching for it but I've been told there are no Adventure Kokoda people on it at all."