I suppose the only thing here .... because non of us are in disagreement about what actually happens (quite satisfactorily to all concerned it seems) ..... is that it isn't what CAP413 says.
As far as I (and presumeably Will who started this) am concerned the written proceedure says the abbreviated call sign should only be used by the A/C after it has been used by ATC. Thus my earlier "conversation" should be ....
Farnborough Radar, G-BSBA
G-BSBA, Farnborough Radar pass your message
G-BSBA is a PA-28 ...... request XYZ
Roger BA XYZ commences ......
Only from that stage should I appreviate to G-BA.
If I am picking this up correctly then both MATS1 and CAP413 give ATC the lead and A/C shouldn't abbreviate until after ATC have.
It might therefore be representative of the real situation if the gospels say that rather than "
MATS Part 1 says that once satisfactory two way communication with an aircraft has been established controllers are permitted to abbreviate the callsign" ...... "once satisfactory two way communication has been established between an aircraft and ground station, the aircraft's call sign may be abbreviated"
That would "bless" the current practise and allow either party to commence use of the abbreviated call sign (but not too abbreviated Steve
)
DGG