Bizarre: Flights Receive False Collision Alerts At DCA Airport

A Traffic Collision Avoidance System [TCAS] ‘Traffic Advisory’ alert is issued when proximate traffic closes to within approximately 40 seconds of potential impact. An aural ‘traffic, traffic’, alert is generated, and a visual depiction of the conflicting aircraft displays its relative positive laterally, as well as vertically - including climb or descent information. A TCAS Traffic Advisory [TA] does not normally warrant direct intervention upon the flight path by pilots. It serves usually as a