Indeed it would totally amaze me if a UK FTO pushed its piston fleet through
PRNAV approval, at a cost of perhaps £5k-10k per aircraft, for the paperwork (totally irrelevant for any IR training purposes, anywhere in Europe AFAICT) but a zero functional improvement.
OTOH if doing a significant avionics refit anyway, only a fool would not absolutely insist on less than PRNAV. And very very few UK shops can actually deliver that at present.
Aircraft approved to the more stringent accuracy requirements may not necessarily meet some of the functional requirements of the navigation specification having a less stringent accuracy requirement.
I don't know what they are talking about. If they mandated an
EHSI (enabling a multi waypoint route to be flown hands-off, with the course pointer always showing the current track, thus ruling out a mechanical HSI with GPSS retrofitted, because the CP on that does not move, compromising situational awareness) then it would make some sense. But they don't.
and therefore dangerously, difficult.
"Dangerous" assumes operational relevance, no?
I'd say that a Major mod requirement for
TAWS would be dangerous. (it probably is, but EASA/Eurocontrol are nothing to do with aviation; it's just a nice retirement number for failed ISO9000 quality managers and other assorted control freaks).
Right, I think I've got it:
- Approval for RNav approaches does not automatically include approval for PRNav
Yes.
- Approval for BRNav and for RNav approaches is quite easy to get
Yes, generally. Subject to VHF-GPS interference checks - see
AC 20-138A or a similar EU spec (which I have as a PDF but the URL is now dead).
- Approval for PRNav is more difficult to get, for no real reason except beaurocracy
Yes.
- IO540 assumed, because my aircraft aren't jets, that they're not PRNav-approved
- Bookworm has attended a talk by my boss, and, based on what was said at that talk, believes my aircraft are PRNav-approved
Now that I'm at work, I've been able to dig out a couple of the certificates. In fact, IO540 and Bookworm are both only partly correct - of the first two certificates I looked at, one aircraft is PRNav-approved, and the other isn't! I'm not sure about the other two Duchesses, I'll have a look at their paperwork later.
Amazing. I wonder why any FTO would bother at all.