Originally Posted by
Discorde
The advantage of 3- and 4- (or more) runway airports is obvious, preferably with different directional orientations to facilitate less hazard crosswind operations and - when the wind is light - variable direction runway usage to selectively alleviate noise pollution in different locations near the airport.
3, 4 or more runways, yes. Heathrow may or may not get a third runway – decision not yet made – but no-one's even started talking about the next stage: lengthening of the new third runway and/or adding a fourth. Those will surely be demanded in due course by the airport operator, BAA. How else, BAA will say, could Heathrow be a viable 'hub' to compete with Charles de Gaulle and Schiphol?
Different directional orientations? Many major airports seem to get away with runways in one orientation only. Heathrow once had crosswind runways forming a nice hexagon, but they're now taxiways.