Originally Posted by
Stagformation
Absolutely, it was a non-standard discourse. But however you look at what was said, PAT 25 requested the change to visual separation. Meaning PAT25 correctly believed he was under standard 1.5nm/500ft separation at the time and that he needed LC approval for Visual separation to be applied. The change in the separation standard being applied did not happen until the LC accepted PAT 25’s traffic visual report and authorised the change. It’s not an automatic change made just on the pilot’s say so, ie by reporting visual, which I think is what you may be implying (happy if you correct me). Both pilot and LC are necessary (and both made errors here).
I may be mistaken, but my understanding is that the controller doesn't really have the option to deny visual separation. The regulations don't mention any response except 'approved.' The word 'approved' does seem to imply that it could also be denied, but there's no mention of how, when, or why that would be done. Even if they do have the option to deny, as far as I can tell there's no guidance on how to make that decision. Obviously there's no way for a controller to know whether a pilot truly has the correct aircraft in sight.