Coverage depends on ground receiver reception and is not a complete picture of traffic.
The hex code is the aircraft's ICAO 24-bit address, broadcast by its ADS-B transponder. It is the key used to match live position reports to this registration.
An inadvertent encounter with convective-induced turbulence upon entering cumulonimbus clouds.
Incomplete and incorrect coordination between air traffic controllers that resulted in the 777 and the two C17s being cleared to maintain the same altitude. Contributing to the incident was the controllers’ non-adherence to established communications phraseology and incorrect data entry into the radar data blocks for each aircraft.