Reach Callsign - any logic to callsign numbers

[Robin]

Is there any logic to the RCH callsigns block’s

Is there any other callsign Reach callsign blocks, for type of cargo, destination or departure location, unit or base??????

I would suspect that other fixed flight regular callsigns, could be for example;

1: Must be one for the standard mail flights (to Airbases and countries for internal mail, documents etc)????

2: Must be one for brining in equipment and spares (i.e. radio; tyres for aircraft and ground equipment, for items that need replacing or repaired away from station????

3: Must be one for standard personnel carrying people between bases and to and from the USA (just like a mini Airline service), often you see people getting off aircraft, who are not aircrew?????


There must be some logic to the Reach callsign blocks???????

Any ideas??????????