A DAY of searching thick bushland has failed to find Des Porter's missing vintage bi-plane or his five passengers.

As many as 16 helicopters left the Kenilworth showgrounds about 5pm after a day of fruitless searching through national park, marsh and mountain country to the north and southwest of the tiny Sunshine Coast hinterland town.

Pilot Des Porter, 68, had five passengers aboard his prized red 1930s bi-plane when he activated an emergency beacon about 1.30pm Monday.

Police have released the names of the five passengers.

They are Mr Porter's wife Kath, 61, Manly West couple Les D'Evlin, 75, and wife Janice, 61, and John and Carol Dawson, both 63.

The operation, systematically checking an area between Gympie and Nambour, began this morning with seven choppers.

This afternoon, activity ramped up with another eight helicopters sourced from throughout the region.

The Courier-Mail understands a refuelling tanker was set up at Kenilworth to save time and fuel for the rescue teams.

There has been no sign of the de Havilland DH84 Dragon, carrying pilot Des Porter and five passengers, which reportedly struck trouble over the Jimna Range near Kilcoy yesterday afternoon.

Police established a search command post at the Kenilworth Showgrounds, on the Sunshine Coast hinterland, as the search for the missing plane continued.

Holidaying locals have turned up in their droves - some camping nearby - to check out the commotion and spectacle of almost 10 helicopters landing and periodically taking-off again from the site.

Some locals on motorbikes have approached police with details of remote and partly inaccessible forest trails they've ridden on in the hope of finding the downed aircraft.

The Australian Maritime Safety Authority's Rescue Coordination Centre Australia is coordinating the operation over an area of up to 1500 square kilometres.

Most helicopters were acting as spotters and there are five designated search and rescue helicopters, including three AGL Action Rescue choppers, EMQ and Careflight crews.

Personnel on these choppers include a pilot, air crew/winch operator, rescue crewman, who could be dropped into an emergency, intensive care paramedic and a flight doctor.

All of the helicopters are working their way through grid patterns designated by AMSA.

AMSA's Dornier fixed wing aircraft, fitted with heat-seeking technology, also has been involved in the search.

The Dornier aircraft, flying at 10,300 feet (3139m) and travelling 157knots (287km/h) has completed a series of flights, but has not yet found any sign of the lost plane.

Its most recent runs have been focussing on an area west of Imbil, including parts of the Amamoor State Forest. Nearest towns to this zone would be Kandanga, Imbil, Amamoor and Kenilworth.

The Australian Maritime Safety Authority's Rescue Coordination Centre Australia is coordinating the operation over an area of up to 1500 square kilometres.

Action Rescue CEO David Donaldson said it was a slow search due to hilly and forested terrain.

Mr Donaldson said human eyes, not technology, held the key to success.

"More pairs of eyes is what will find this aircraft," he said.

"We need to fly low and be right over the trees looking down. You could be a few hundred metres from the aircraft and not be able to see it."

Mr Donaldson said observers would look for signs, like damaged tree tops, and did not expect to see the bright red aircraft intact.

The search operation includes three helicopters from AGL Action Rescue, one from Emergency Management Queensland, Careflight on the Gold Coast and two others sourced from Sunshine Coast McDermott Aviation.

There are five designated search and rescue helicopters, including the AGL Action Rescue choppers, EMQ and Careflight.

They are working their way through grid patterns designated by AMSA.

Personnel on these choppers include a pilot, air crew/winch operator, rescue crewman, who could be dropped into an emergency, intensive care paramedic and a flight doctor.

Earlier, it was reported that seven helicopters would this morning lead a full-scale aerial search for a vintage aircraft that disappeared over the Sunshine Coast hinterland.

There has been no sign of the de Havilland DH84 Dragon, carrying pilot Des Porter and five passengers, which reportedly struck trouble over the Jimna Range near Kilcoy yesterday afternoon.

At 9am it was revealed that among the five passengers were copilot John Dawson and his wife Carol.

John's brother Ian Dawson said Mr Porter and John had been friends since high school, and would spend almost every weekend together, either working on the plane or flying it.

"He (John) is his copilot, the navigator. I called him the ticket man," Ian said.

Ian said his brother was not a qualified pilot, but loved to work on the plane and help where he could.

The Dawson brothers, from Wynnum on Brisbane's bayside, have worked together for the past 36-years at a smash repair shop on Wynnum Rd.

Together the pair restored a Lotus Cortina and a Holden EH.

Ian said the cars are his brother's pride and joy.

John never had children, Ian said. John's mother, in her 80s, was very distressed by the news that her son was missing, Ian said.

Ian said he was hopeful that Mr Porter and his five passengers would be found safe.

The pilot, Des Porter, who also owns an auto repair shop in Wynnum, was known to keep meticulous records about his aircraft.

Shane Gilchrist worked opposite Mr Porter's automotive business for 16 years, and said he was well-known in the Wynnum area.

"He's a genuine, straight-shooting, all-round nice guy," Mr Gilchrist said.

"His integrity is without question."

Mr Gilchrist said Mr Porter used to compete as a drag-racer.

"I just hope against hope he somehow landed safely," he said.

At 7am it was reported that the Australian Maritime Safety Authority's Rescue Coordination Centre Australia is coordinating the search, which would step up a gear from 8am.

It reported that an overnight mission involving AMSA's Dornier aircraft, fitted with heat-seeking technology, did not report any sightings of the aircraft or reveal any new information.

Today's search will include seven helicopters departing from Maroochydore. Weather conditions in the area have not been favourable but a forecast indicates they are likely to improve throughout the day.

The search area is approximately 540 square nautical miles, covering a region west of Gympie and south to Nambour.

The red biplane left Monto on Monday morning en route for Caboolture with six people on board, including the pilot.

The aircraft contacted air traffic services in Brisbane later that afternoon requesting assistance before activating an emergency beacon at approximately 1.30pm.

The beacon is no longer being detected and RCC Australia has been unable to establish communications with the aircraft.

Search efforts on Monday afternoon involving two AGL Action or recover any new information.

AMSA will issue its next update following this morning's search.

Police say a major incident room has been set up at Maroochydore station.

Earlier, it was reported that 50-eight years ago this month, young Des Porter was saved from a sinking plane wreck that killed his father and brother when rescuers used an axe to hack through the fuselage to reach him.

On Monday night, nearly six decades after the crash that led to his devastated mother forbidding him from ever flying again, Mr Porter and his five passengers were missing after their plane disappeared over the Sunshine Coast hinterland.

And Mr Porter, 69, was in the same model plane in which his father and brother were killed - a de Havilland DH84 Dragon.

The identities of the other passengers had not been confirmed last night.

Helicopters and a fixed-wing plane were sent out as part of a large-scale search mission after the skilled pilot from Wynnum West made a radio call for help yesterday afternoon. The search was expected to begin again at first light on Tuesday morning.

The father-of-two and his passengers were on their way home to Caboolture from the Monto Fly-In, an air show west of Bundaberg for vintage plane enthusiasts, when they vanished over heavy bush.

Piloting his much-loved 1934 DH84 Dragon, called Riama, Mr Porter made radio contact with a friend as he passed over Gayndah, west of Maryborough.

The Courier-Mail understands Mr Porter was unconcerned when he chatted to the friend at 11.51am.

But by early afternoon, he was calling Brisbane Air Services for help, activating an EPIRB at 2.45pm, 45 nautical miles northwest of Caboolture.

The Australian Maritime Safety Authority tried to reach Mr Porter, but communications had been cut.

"We have two AGL action rescue helicopters from Maroochydore searching an area northwest of Caboolture and the Dornier (fixed-wing plane) is leaving Essendon, expected to arrive at 7.15pm," a spokeswoman said.

"They have electronic equipment, radar and heat-seeking equipment they can use to search in the dark."

Mr Porter's father, Stan, flew de Havilland Dragons in the 1950s.

In 1954, he crashed and destroyed one of the planes at Archerfield Airport while preparing to deliver copies of The Courier-Mail to Gladstone.

Stan Porter survived that accident, but only months later he was not so fortunate, when the DH84 Dragon with he and his two sons on board clipped trees and crashed into Doboy Creek, near Tingalpa in Brisbane's east.

Reports at the time said three men swam to the plane and heard Desmond crying "Help me".

After breaking their way into the plane with an axe, they saw Desmond trapped in the cabin with water up to his chin.

The front of the aircraft broke away on impact. The bodies of Stan and Keith Porter were found in about 5m of water a day later.

At the request of his mother, Inez, Des Porter gave up the love of flying he had inherited from his father.

But five decades after that terrible tragedy, Des renewed his love affair with the skies after a massive restoration project to rebuild another vintage Dragon.

A family friend at the couple's home said they were desperately awaiting news of the Dragon and its passengers.

Last night, Imbil residents said they had seen helicopters hovering over their town at about 5.30pm.

They flew west towards Borumba Dam.

The terrain, which takes in Imbil State Forest, Amamoor State Forest and Conondale National Park, is heavily wooded with only narrow tracks used by motocross enthusiasts.

Residents say aside from the dam, there would be very few places open enough to land a plane.

But an aircraft going down in the lake would have certainly been seen by fishermen and campers who frequent the area.

A distressed Caboolture Aero Club member said the plane was due back in the afternoon but hadn't arrived.

"It's normally based here and it's not here," he said.

"We don't know any more than that."

- Additional reporting by Kate Kyriacou, Alison Sandy, Brooke Baskin and AAP

