VOR
In analysing the ‘ball park’ change in risk from C to E over D, you assert, among other things, that:
The controller does exactly the same in Class D – so we would say, not change in that risk component. … The pilot operating in Class D airspace – effectively no change – so the risk stays the same.
My understanding of Dick’s point is that because the controller’s workload is reduced – that is, she doesn’t have to work the VFRs in E that would otherwise have been C – the controller can concentrate on separation in the Class D where, according to Dick, the collision risk is comparatively higher. In other words, the D controller can
do more than she would otherwise be able to do to keep the D traffic separated. You acknowledge the workload point, then confuse me a little when you say:
… the VFR flights effectively become invisible to the controller, so no service provided, workload probably decreases, and yes, the level of overall risk that is managed by the controller comes down.
You also say:
So we have controller related risk going down, and pilot related risk going up. Instinct and experience tells us that there would be a net increase in risk.
With the greatest respect, and without suggesting DickNAS is anything other than a debacle, I hope Airservices’ safety case isn’t based on “instinct”.