Originally Posted by
FullOppositeRudder
With quite a lot of commercial flight operations using the airline flight numbers these days for radio comms, the problems may be more likely administrative rather than operational.
Adding another letter on the end of the existing three letter suffix seems a reasonable solution. The British and the French operate thusly - and have done so for years - so any potential issues there would seem to have been resolved to the satisfaction of all parties. Where ops require aircraft identification by rego rather than flight number (or military designation), more precise radio procedures may be required, and everyone needs to be alert for the possibility of potential errors, but surely we are up to that. The expansion of data base requirements at all levels to fit the extra character needed could be something of a challenge, but we came through Y2K pretty well unscathed. In any event - we already have RAAus aircraft in the operational mix using the 2+4 numerical combinations, so changes in the mainstream aviation system should be quite workable if and when they become essential.
Finally, from what read, I think ICAO may well need to be involved in any change anyway.
I think the database concerned are invalid. Even going back to the 70s, airline departure control systems could put in any registration format you wanted. The registration in the table of registrations for each carrier/aircraft type (as for example QF handled a lot of carriers in it's DCS) could be input however one wanted to - e.g. VHEBA, VH-EBA, etc. etc. the only requirement being when inputting the registration on a flight set up as a 747-238B, one would have to enter the registration precisely as it appeared in the table for that airline/type. If there was a change, for example, dropping or moving the hyphen, then updating those records would be about 10 minutes work and from an airport perspective, would only require the controller of the flight to change the registration. In fact, the way it'd probably be done is to set up additional registrations in the new format, get each flight controller to update the registration, then remove the old formatted regos. I assume other systems would be similar, ATC for instance as they already have to cope with an almost infinite number of combinations.