A go-around or missed approach is when a landing is aborted at the last minute, on final approach. Instead of touching down on the runway, the plane overshoots it and climbs to a given height before recommencing its approach and landing sequence from the beginning.
Standard go-around procedures are included in every airfield’s published approach instructions for pilots. In some situations, the air traffic controller needs to provide additional instructions in order to maintain separation from other aircraft. A go-around may be initiated by either the pilot or the air traffic controller. The most common reason for making one is that the aircraft is not stable enough on its final approach. At this point the pilot has to reduce the plane’s speed and height, and put it into so-called landing configuration: flaps open, undercarriage down. If any parameter is incorrect as the runway approaches, the landing has to be abandoned. Unexpected changes in weather conditions during final approach may also force a go-around, as can circumstances on the ground – disruption of the signal from the instrument landing system by the tail of a taxiing aircraft, for instance. Or the air traffic controller may have to withdraw landing clearance because the previous aircraft using the runway has not left it in time. At busy airports like Schiphol, approaching aircraft are lined up as efficiently as possible, but always with a minimum separation of three nautical miles (about 5.5 kilometres). If a landing aircraft fails to clear the runway quickly enough, the one behind may have to make a go-around. For the runway controller, it is important to determine the risk of a conflict with other aircraft as quickly as possible and to give any additional instructions needed to avoid it. The approach controller then has to guide the aircraft affected back into the queue of flights waiting to land.