Enhancing SA with type-specific call signs

[DaveUnwin]

"But when LHR hear the call "United 123". he has a flight plan, LHR have the detail and there is a squawk on Radar. Not too difficult to confuse."

I'm very aware that United 123 would not come as surprise to Heathrow Approach, but I think you've missed the point Dave Gittins, go back a bit to the post about conventions - that's the point I and ETOPS were addressing. And you're right that telling everyone on Goodwood's freq that 'IK is a green PA-28 does make everyone's life a bit easier!