no-transgression zone

no-transgression zone (NTZ)

no-transgression zone (NTZ)click for a larger image
In the context of independent parallel approaches, a corridor of airspace of defined dimensions located centrally between the two extended runway centerlines, where a penetration by an aircraft requires a controller intervention to maneuver any threatened aircraft on an adjacent approach. This is normally a 2000-ft (600 m) wide zone.