Good on you, Dick. For one, controllers can over transmit communications if necessary plus there are other methods that can be used; simply, " ABC standby". To bring up the incident Of the 747 SP is rubbish and not relevant. When incidents are investigated ATC's/Pilots manufacture all sorts of excuses and this case it is of no relevance. Besides, you've recommended/presided over some crap.......the latest being GAAP to Class D Procedures.