All I really know is that it's referred to as SODPROPS, or Simultaneous Opposite Direction Parallel Runway Operations. I believe it's put into use when when the wind is runway-neutral (calm/variable to where one set of runways gains no advantage over the other). In general (not just at SYD
), it's used in order to comply with noise abatement regulations, weather, other hazards, and to minimize taxi times for aircraft (for example at SYD
where the terminals are much closer to one end of the runways than the other).