Ballyboley,
"I really like the half of the CAS equation"
It should be half the groundspeed (not CAS) and multiply by 10 to get a 3deg ROD. (same as 5* GS). It's easy to do quickly and great for descent, non-prec app etc.
I don't think CDA's are possible to SS 05 at all times and I don't think the approach you did was expected to be a CDA either. I was told it was due to airspace restrictions to the south. We need a SS director guru to correct me on this.
Could the same or similarly informed Guru tell us who is are the worst at sticking to speeds especially 170 to 5 or 160 to 4? It is amazing how close some a/c get even when you have been sticking well to the speeds. Now and then we keep 160 to 2 (or 170 to 3) to compensate for the small gap.
