It now seems clear that the UK AIP states that a maximum IAS of 185 knots is imposed on all missed approaches (unless lower is specified on the chart, of course). This tells me that anyone who uses a higher speed in the missed approach will run the risk of infringing airspace that must be avoided - or get too close to an awkward hill. I wouldn't be brave enough to use a higher speed, whether the company allows it or not!
If, as stated, the CAA FOIs are happy with a higher speed, I'd suggest that they probably don't know much about their own AIP, let alone Volume 1 of Pans Ops. I have my doubts that the CAA actually tests each new procedure for all speed categories at normal speeds. That would not seem to be required by the AIP reference but, oh yes, we
ARE talking about the UK CAA aren't we...
keithl... I hear you and understand where you're coming from. I offer the following for consideration.
Yet the max speed for the same phase, for a Cat E aircraft is given as 230kts. So much for the calculated speeds.
I would venture to suggest that an AIP speed limit of 185 knots means that it affects Cat E as well - unless there's a note on the chart that specifically caters for Cat E. I can't see anything in the quoted AIP reference that alleviates this situation. There are no civil Cat E aircraft left now that Concorde has gone, but I guess that they probably fly Cat 3 ILS approaches everywhere in the UK, so a missed approach might be a bit academic.
Or it might just be that the UK AIP hasn't kept up with the latest procedure design practices. I suspect that, if I was working in the UK, I'd be seeking written clarification from the CAA.
Now, "185 kts on the chart". Chart conventions vary. I know Aerad best, and they use 180kts for turning circles on approach charts (including MAP) and that is regardless of category. I've looked in Jepp. but can't find what speed they use. Perhaps someone here could oblige?
I feel sure that charting conventions are adopted for ease of ensuring that all the charts are the same size and same scale. If they were to attempt to depict the actual speed then, in places where speeds directly reflect Pans Ops, either the chart size may have to be enlarged (ie not easily fit in the book) or the scale of the chart has to be changed to accommodate a huge turn radius. That wouldn't be efficient for a mob like Jeppesen or Aerad, I'm sure.