Originally Posted by
ftrplt
It depends what training/app endorsement CessnaPete holds as to whether it is actually a problem.
I have spoken to professional pilots who aren't confused. Again it depends on the training received by these professional pilots of yours and what approaches they are qualified to fly.
Doesn't really matter if some believe WAAS (which is actually one of a few SBAS service providers) is in Australia, we don't have charts published with LPV minima and the acft avionics wont work if they tried to fly LPV functionality in Oz anyway, so it is irrelevant.
If you started with a clean-sheet design for GPS approaches to today's capability would you design it they way it is now - probably not. However GPS approaches have evolved over 20 odd years so it has been constrained within the ability of exisiting avionics and autoflight systems to evolve with the increased capability.
I think of it differently - pre-GPS approach days you achieved your entry level instrument approach capability with NBD, and if it was real smick you had an RMI instead of fixed card. Some people could even fly VOR approaches! If you then wanted the really good capability you trained to fly ILS approaches. This certainly wasn't a transition without learning challenges.
I think of RNAV NPA as the entry level capability (like NDB/VOR app but better), LNAV/VNAV as the next level capability (note quite CAT I ILS), and LNAV LPV as ILS CAT I. Yes, the fact that you now effectively have 3 different capabilities within the same system does add initial understanding complexity - it just takes some effort to learn. You had similar learning challenges moving from NDB, to VOR, to ILS in the old days.
This evolution of GPS approach capability is not unique to Australia, in fact the evolving terminology is an effort to align terminology across the world. Short term disruption for longer term gain given the capability evolution over 20 years. The FAA is going through similar terminology/nomenclature changes.
You state ILS is simple - true if flying to CAT I only. Definitely not simple if you wish to extract the full ILS capability and fly to CAT II, or CAT IIIA / IIIB with AL and rollout.
I would equate your 'simple ILS' to flying RNAV NPA's only - pretty simple if you don't want to train and qualify to fly the enhanced GPS approach capability. Don't worry about anything other than the LNAV minima box, monitor the intermediate step heights, and don't bust the MDA.
(Dick - I will get back to you on the immediate post above, gotta step out - but its an LNAV NPA - with the avionics providing the internally generated GP, the approach is not designed with a 3 deg GP, its the acft's avionics effectively automating the DME/ALT scale. One of the documents I referred you to mentions Lnav+V, I will need to look again).
I hold an Instrument Rating, thats all thats required to fly any IFR approach in IMC in the UK.
GNSS approaches need to be initially endorsed, and then checked on the normal yearly Rating renewal flight.