Originally Posted by
EastCoaster
Moggiee:
"As for cloudbase, the acceptable minimum on an ILS approach is 0'. "
Only for CAT III ILS approaches. CAT II approaches have a 100' cloud base minimum, and CAT I minimum is 200'.
A common misconception.
The minimum DH for Cat I is 200' and for Cat II is 100. But that's not what I was saying. If you check publications such as the UK AIP it clearly states that the minimum permissible cloudbase for commencing the approach is 0' and that it's the RVR which triggers the approach ban (usually 550m for Cat I and off the top of my head, 300m for Cat II. I find that an awful lot of inexperienced pilots fresh out of their CPL/IR believe that the cloudbase is the limiting factor on an approach ban, when in fact it is not.
As I say, a very common misconception.