WITH a handshake, a few signatures and the handing over of two keys, Cathay Pacific Airways became the private owner of its 15th Boeing 747-400. It was rather like taking delivery of a new car. Except in this case US$140 million changed hands. Final formalities included the manufacturer phoning the bank to make sure the money had been transferred. It was back in 1989 that the order for Cathay's latest 747-400 was confirmed. ''You have to confirm 24 months before work is started and pay 25 per cent in advance,'' said Mr Peter Gardner, Cathay's technical vice-president for the US. ''This is when the plane is locked into the production line. Any changes after this stage, even moving a galley or a toilet one inch, cost an additional $1 million. Work started in earnest in 1991. Four months were spent collecting some six million parts from 15,000 suppliers around the world. Then the plane progressed down the 747-400 assembly line in the largest building in the world. The plane started to take shape when the wings were attached to the centre section. Then the front and back sections were added and the landing gear, rigging and hydraulics installed. This is no small job as there are 232 kilometres of wiring and 196 kilometres of tubing in a 747. Finally, the engines, which cost $8 million each, were fitted in a process that took six weeks. Next the plane was rolled out of the assembly hangar to the paint shop, where it spent four days getting its new identity. Before test flights the plane was weighed and balanced, fuel tanks were checked for leaks, and a good old-fashioned compass was fitted. ''If all else fails then they can still use the compass,'' said Mr Gardner. After the engine runs and avionics checks, Boeing gave the plane its first test flight. Happy with its performance, Boeing signed the aircraft over to Cathay. At this point Cathay pilots put the plane through its paces themselves. It came through with flying colours. ''She had one defect. The wiper blade on the captain's window was not flush to the screen,'' said Mr Gardner. ''That is like saying the ashtray in a new car is faulty.'' That left only the paperwork. And the two keys that were handed over? They lock the flight door.