Safety takes priority in the handling of air traffic. This also applies for the use of the take-off and landing runways. Whether a runway can be offered for take-offs or landings depends on the wind, visibility, the condition of the runway and the rigidity. The availability and accuracy of the Instrument Landing System (ILS), which can be used for landing even in poor visibility conditions, and the lighting equipment may also be determining factors for the availability of a runway. Which of the available runways are deployed is determined on the basis of the GPBS. The GPBS determines which runways and runway combinations merit first preference from the point of view of safety and which cause the least noise pollution.
This means that preferably, a combination of runways will be offered that causes nuisance to as few people as possible. This system works as follows: a combination is created from the runways available for use, with preference always going to the runways that cause the least nuisance. By day, the combinations consist of two take-off runways and one landing runway or two landing runways and one take-off runway, depending on whether there is more outbound or more incoming traffic. During night-time hours, one take-off runway and one landing runway are in use. Which of the available runways is ultimately used for outbound flights therefore depends on considerations concerning safety, capacity and noise pollution.
LVNL decides which runways are offered. It takes account here of the determining factors mentioned above: safety, capacity and environment (noise pollution). With the aim of reducing noise pollution, LVNL works with the noise preferential runway use system (GPBS). However, consideration for noise pollution must never be at the expense of safety.
During night-time hours, only one take-off runway and one landing runway are in use. In principle, these will be the Kaag runway and the Polder runway. These are the runways that cause the least noise pollution overall, because their approach and departure routes largely run above less densely built-up areas than the other main runways. It may be necessary to switch to a different runway due to weather conditions (strong westerly or easterly winds, poor visibility), unavailable navigation equipment or runway maintenance. Usually, this will be the Zwanenburg runway or the Buitenveldert runway. In principle, the Aalsmeer runway is no longer used at night. The Schiphol-Oost runway is always closed at night. However, in certain conditions, for safety reasons, it may be necessary to deviate from this principle.
By day, in normal weather conditions and with normal runway availability, traffic can be handled on four runways: the Polder runway, the Zwanenburg runway, the Aalsmeer runway and the Kaag runway. At peak landing times, two runways are used for incoming traffic and one for departing aircraft, while at peak take-off times, two runways are used for take-offs and one for landings. With the present five-runway system, the Buitenveldert runway is used less intensively than with the former four-runway system.
The Schiphol-Oost runway is a relatively short runway. On this runway, the biggest jet aircraft cannot be handled. The Schiphol-Oost runway is used, among other things, in the following circumstances:
The Schiphol-Oost runway may not be used at night (between 10.30 p.m. and 6.00 a.m.), either for take-off or landing. If Schiphol-Oost runway is in use for landing by day, the residents of Amsterdam inner city and south-west Amsterdam, in particular, experience noise pollution.