In New Zealand, regional airlines are currently showing (and have been for some time actually) as a hybrid of the ICAO and IATA callsigns. For instance, flightaware.com/live/flight/RLK8077
This flight doesn’t exist. RLK is Air Link, which is the ICAO callsign for Air Nelson. The IATA flight code is NZ8077, but the callsign used on the radio and on the radar is RLK77, or perhaps RLK077.
Mount Cook Airlines is another good example:
flightaware.com/live/flight/NZM5221 NZM (Mount Cook) 221. The correct ICAO callsign is NZM221. The correct IATA callsign is NZ5221. But the CORRECT callsign is NZM221.
So, why is the data showing on here a blend of the two callsigns, creating one that is incorrect on both counts? What was wrong with the old way, which was to always display the ICAO code that came straight from the feed provided by Airways New Zealand?