EntityQ333044· pop 28· linked from 289 articlestraffic collision avoidance systemSign in to saveaircraft collision avoidance system which actively interrogates other aircraft transpondersConnectionsGlobal Positioning SystemEntityInternational Civil Aviation OrganizationEntityFederal Aviation AdministrationEntityvariometerEntityÜberlingen mid-air collisionEntityground proximity warning systemEntitytransponderEntityautomatic dependent surveillance-broadcastEntityflight lengthEntityairborne collision avoidance systemEntityNew DelhiEntityGenevaEntityZurichEntityradioEntitycompassEntityfrequencyEntityaircraftEntityWayback MachineEntityradarEntityLondon Heathrow AirportEntityCategoriesAircraft collision avoidance systemsAviation risksAvionicsWarning systems