Qantas is donating its first Boeing 747-400, known as City of Canberra, to the Historical Aircraft Restoration Society (HARS), based at the airport.

It will be the first 747-400 in the world to be preserved for public display and the biggest aircraft to be on show at the HARS facility.

The aircraft, registered as VH-OJA, made Australian aviation and Qantas history in 1989 for the longest non-stop commercial flight from London to Sydney in a time of 20 hours, 9 minutes and 5 seconds, a record that still stands.

Its final flight will be its shortest, estimated at just 15 minutes, but the planning to land the flight at the small airport has been just as meticulous.

There will be four pilots on the plane, led by Captain Greg Matthews, who is Qantas' manager of training and checking for the 747. Also on board is first officer Peter Hagley, a 747 technical pilot, second officer Michael East and Captain Ossie Miller, the 747 fleet captain and Bowral resident.

The pilots have spent more than 25 hours in the Qantas flight simulator preparing for the landing.

Qantas said the 747-400 aircraft usually landed on runways 45 metres wide and much longer than the Illawarra airport's 1819 metres.

The Illawarra airport's runway is just 30 metres wide, and the aircraft has a wingspan of 64 metres so the two outside engines will hang over the runway's edge, but Captain Miller said the width was more than adequate.

The pilots expect to leave Mascot's domestic terminal, taking off towards the south and climbing to 4000 feet.

"This is quite low considering the aircraft is capable of flying to 45,000 feet and cruise in the mid to high 30,000s," Captain Miller said. "We'll depart Sydney with 20,000 kilograms of fuel. That will give us an opportunity to hold or if we need a second attempt at the approach and there will be enough fuel to get back to Sydney."

Captain Miller said Qantas had reduced the tyre pressure to minimise any runway surface damage.

"We worked with Boeing on this," he said. "We don't want a tail wind ... ideally we will have no wind or a southerly."

When the landing has finished, a specially borrowed tug will leave the vehicle just short of the display area prepared by HARS.

"There is still a certain amount of work engineers will need to do for the long-term storage ... some equipment needs to be deactivated or taken off," Captain Miller said.

The aircraft's farewell and delivery to HARS is proving to be an emotional experience for past and present Qantas employees, Captain Miller included.

"It is just a fabulous opportunity for me," Captain Miller said.