WHEN an economic analysis on Hong Kong comes up with the main finding that capital expenditure relating to the airport and external trade will be big drivers in the economy over the next few years, the initial reaction is to file the document in the wastepaper basket. You do not need 20 economists and 40 software engineers to spend 20 man-years tweaking the computer model to come up with that sort of stuff. But it is easy to forget the ramifications of building the airport. Take the impact on the property market. Sixty-two hectares of property along the airport railway will eventually be released on to the market with a consequent impact on residential and office property prices. According to the Bank of East Asia (BEA) report, total housing supply up to last year was 1.8 million units, while end-user demand is estimated to be 1.71 million units. BEA reckons that true demand was adequately supplied between 1989 and last year but the presence of speculators or investors in addition to genuine users drove prices up. The Mass Transit Railway Corp (MTRC) estimates that 24,000 residential units will be built beside the railway in the next few years. And BEA has realised this will significantly alter the property equation. 'These units, together with normal supply, could fill excess demand and hence stabilise property prices,' said the report. If the airport works out as hoped, if the Special Administrative Region works out as hoped, then the centre of the map of Hong Kong is going to move. Central will stay Central - but anywhere else on Hong Kong Island outside the prime, core Central area will instantly become less attractive. The airport railway corridor and routes across the border will become the sought-after residential zone. Over-priced dives in Mid-Levels will lose value once people can choose between a well-designed home in a well-designed satellite suburb close to an airport MTR station and where they live now. The chances are that some parts of Hong Kong Island will fall off the map entirely. Fringe zones such as Aberdeen and Pokfulam will lose whatever attractions they hold and even the Peak will be a draw only because it is the Peak. See you in Commuter Land.