Hello gentlemen,
I think this question is bugging me for quite some time and now I will ask it here as I am sure some people will be able to give me a good answer. When I am looking at a lot of airports these days I find something like this list when it comes to selecting an approach:
Note this is taken from SFO for runway 28R:
a) ILS OR LOC RWY 28R
b ILS RWY 28R (SA CAT I)
c) ILS RWY 28R (CAT II - III)
d) RNAV (RNP) Y RWY 28R
e) RNAV (GPS) X RWY 28R
f) RNAV (GPS) Z RWY 28R
g) LDA/DME RWY 28R
h) LDA PRM RWY 28R
i) RNAV (GPS) PRM X RWY 28R
j) QUIET BRIDGE VISUAL RWY 28L/R
k) TIPP TOE VISUAL RWY 28L/R
From what I understand, in the real world for normal commercial operations
(a) Radar required, is the most common approach used in the real world, when the weather is fine
(b,© Radar required and other requirements, is used when visibility forces us to use them
(d) Authorization required, RF, GPS, Radar required. Why do you need an authorization for this? Why wouldn't all airlines use this procedure on a day with fine weather instead of (a)
(e) Radar required, DA is 1140 ft, ok (a) has a lot lower minimums, but with nice weather why wouldn't I use this one instead of (a)?
(f) Radar required, DA is 287 ft for LPV, and 641 ft for LNAV/VNAV, 760 ft for LNAV. Could somebody explain what LPV is?
(g) Radar and DME required, this is a special localizer-based instrument approach, why does an airport with ILS do need this at all?
(h) Radar, DME and dual VHF comm required, again a special localizer-based app, I guess this is all about seperation and movements per hour
(i) Radar and dual VHF comm required, why do I need this when I have (g) and (h), just in case LDA is unavailable?
(j),(k) ok, this would be a choice when weather is fine and I should take care of my seperation myself
My question is: In normal operations, nice weather conditions, is it like airlines use (e), (f), (d) or (i) instead of ILS-based approaches? One small question regarding the naming, what is the difference between a RNAV RNP (d) and RNAV GPS (e) approach?
Thanks for your help.
Best regards,
Martin Schiewe