I thought I'd give an example (all identifying features taken out), I think there is more than one moral in this story. And ATC arent beyond learning, so I hope we can get some feedback from RPT flights to help us understand whats going on in the aircraft.
I had an inbound RPT Jet to a CTAF(R) airfield, I cleared it to leave CAS on descent ,etc etc "No Reported IFR Traffic". There wasnt at that time!
Anyway, The jet didnt advise it was changing to the CTAF or equivalent. It was observed on radar joining downwind for runway 09 descending through 2500' (from memory). Then a non-RPT four engine prop called taxiing out for a runway 27 departure. (knowing the operator of this non-RPT I know it can get from taxi to airborne in the time it takes to make the taxiing call, and also not the greatest at listening on the CTAF frequency), and realising it was gonna launch opposite direction and on planned route turn towards the downwind traffic, I made a traffic info broadcast to the jet.
Obviously, no response from the jet after 2-3calls. (we would be happy if you just transmitted your callsign as response). Anyway the Prop duly gets airborn off 27 with the jet turning finals for 09. They pass safely as the prop made an early(?) turn.
I was a little bit rattled by this and my tone was prbably harsher than I intended, but when the jet called up to cancel SAR for arrival. I enquired as to whether he had heard any of my traffic calls. He got a bit stroppy and said yes but was too busy on approach checks & CTAF to respond to my call, and I quote "Obviously I was aware of XYZ234".
This could have been resolved with a simple call from the jet when he was going to CTAF on com2, or just using the call to me of "ABC123 Roger"
I hope Im not sounding too preachy, I'm just trying to get a better understanding for pilots of ATC tasks and also for ATC of pilot tasks. Its definately a two-way learning curve (management buzz-word alert
)