A new hi-tech video made for the Provisional Airport Authority by Centro Digital Pictures clearly demonstrates how Hongkong's new airport will have the ability to handle the huge double-decker aircraft of the future. A SINGLE-deck aircraft takes off into the noon-day sun. There's nothing unusual about that. But suddenly it begins to mutate, growing wider, and larger - even growing another deck. Thanks to a hi-tech computer technique called ''morphing'', the Provisional Airport Authority's (PAA) has been able to include this footage in its new promotional video, Flight Path to the Future, highlighting the advantages of a giant-size aircraft thatis expected to be in use by the time the Chek Lap Kok airport is finally finished. These flying behemoths, designed to carry between 600 and 1,000 passengers, are now under development by the world's major aerospace companies, including Boeing, Airbus, and McDonnell Douglas, and are expected to operate between major hub airports in thePacific Rim. Boeing is known to be developing a double-deck successor to the 747, dubbed the 747-X, while McDonnell Douglas is working on the MD-12. Airbus Industrie has thee Ultra-High Capacity Aircraft (UHCA) under development. In a recent surprise move, rivals Boeing and Airbus announced their intention to co-operate on the development of such aircraft. The Mott Consortium, which includes Foster Associates, is designing the Chek Lap Kok airport terminal to accommodate the huge aircraft, and to allow them to load and unload simultaneously on both levels. Foster Associates is the Hongkong branch of Sir Norman Foster's architectural practice. Sir Norman is the architect who designed the Hongkong Bank headquarters in Central, as well as Stansted Airport in Britain. The video points out that half of the world's population lives within five hours' flying time from Hongkong. As a blend of footage shot in Hongkong, and computer-generated animation, the film shows the airport terminal's people-mover system, plus offices and other facilities. It gives an idea of how the terminal will look when it is completed. According to Mr John Chu, president of Centro Digital Pictures, the company that produced the film, the computer animation process employed is called morphing. ''We used a bit of 3-D morphing as we have done in many other jobs,'' said Mr Chu. The computer software used by Mr Chu's team is similar to that used in the making of the film Terminator II - Judgement Day. Morphing is a relatively new technique made available to film makers by advances in computer graphics. Mr Chu said it took 6,000 hours of computer time to make Flight Path to the Future. ''The film is in three parts. One part is live action shot by two teams. Another is computer animation which includes views of the terminal, the plane landing and taking off, and a truck driving away. All of those are three dimensional,'' Mr Chu said. ''Part of the video is made by composing live action and computer-generated backgrounds. People are walking in arcades, but the roof is computer-generated to give people the impression they are walking inside the terminal,'' he said. More than $50 million worth of equipment was used in the making of the video, including gear for filming, computers, sound mixing, and a digital composing system using a $6 million computer system called the ''Henry'', which is the first of its type in Southeast Asia, according to Mr Chu. Making the eight-minute video took two months. The scripting took another two months. The film was shown to the public for the first time last week at the Hongkong International Aerospace Forum. The producer of the film, Gary Thomas, used music by Noel Quinlan in the movie. Brian Blomfield wrote the script while the voice-over was done by Mitch Roberts. Centro was chosen to make the film after the PAA took the project to tender and visited various film making companies in Hongkong. The earlier PAA promotional film, Gateway to the Future, was made by Salon Films.