LPV, LNAV/VNAV, APV, baro-VNAV, +V (merged)

One quickly gets into system dependent features.

For example, if say an airport has a GPS/LPV approach, and you want to fly it coupled, will the GPS give you the option to select and fly the version without the LPV GS? I don’t see how it could.

With an ILS, you cannot fly the LOC and not the GS. Well, you can but only by hand. If you select APR on the autopilot it will capture the LOC and the GS.

How can I find out if it’s WAAS/EGNOS enabled?

A bit of text showing “EGNOS” somewhere? My Garmin 496 says “using EGNOS”. But your year-2008 G1000 may not be capable.

Regarding the PRNAV can of worms, yes Sweden does require training so at the moment we are not allowed to fly the SID and STAR on GPS but an LPV approach is OK (if I’ve understood it correct).

Yes; really idiotic. PRNAV = RNAV 1.0 but GPS/LNAV = RNAV 0.3! The 1st is illegal but the 2nd is legal.

Why the difference? IMHO, GPS/LNAV arrived (from the USA) and sneaked in under the wire before the gravy train riders in EASA could catch it and milk it by making it a Major mod which would create nice work for the EASA Part 21 companies whose ex employees make up much of EASA’s certification staff. By the time PRNAV was being debated, the bottom had already fallen out of the navigation business (GPS did to navigation what the CD did to vinyl records, and a lot of people are very unhappy about both) and ICAO jumped on it.

My KLN94 is illegal for PRNAV SIDs and STARs too, but it contains the individual waypoints

However most modern LPV solutions are today covered by an STC which does PRNAV too. Exceptions might be GNS430W / 530W for EASA-regs. It came up here – not sure of the latest on this – and a 2008 G1000 might be in the same trap.

This answer is highly dependent upon your specific equipment and installation. Please check the Aeronautical Information Manual. LPV approaches require WAAS Class 3 equipment built to TSO-C145A or TSO-C146A and installed IAW AC 20-138A. Older TSO C129 GPS receivers may be for VFR-only use, or may only be sufficient to fly non-precision GPS approaches. LNAV/VNAV and LPV approaches require additional equipment beyond the basic GPS receiver

I think that’s confusing. AC20-138A is ancient and covers the original IFR GPS boxes. The bit saying “LNAV/VNAV and LPV approaches require additional equipment beyond the basic GPS receiver” doesn’t make sense.

OK, so to get a GlidePath indication it must be a LNAV/VNAV approach I guess?

No, you do get a glide slope indiciation (what else would the +V stand for?) … but it is “advisory” only. This means: You have to fly the approach with its stepdown fixes and check altitudes, but for advisory you see a GS too. Of course we all do it that way :-)

Martin, you describe the 172 as TSO-C145a compliant. That means it has WAAS. A non-WAAS approved GPS is TSO-C129.
LPV does resemble precision approach in terms of minimums, accuracy and cockpit indications, but formally it is a non-precision procedure. So the “non-precision” term in the POH supplement does not imply it cannot do LPV approaches.

To upgrade a non-WAAS G1000 to WAAS status is costly. I have seen quotes from EUR 35k to 50k. In comparison, for upgrade of a couple of G430 I have heard EUR 7k to 10k. For G1000 it is surprising that a system marketed as built on LRU – Line Replacable Units – is so prohibitively expensive to give an upgrade that by many is imagined as not much more than a software upgrade. Part of the explanation is that new antennas are required, but still.

Regarding the PRNAV can of worms, yes Sweden does require training so at the moment we are not allowed to fly the SID and STAR on GPS

Sweden requires training for BRNAV as well! The question is – are there any ATOs approved to give PRNAV courses?

but an LPV approach is OK (if I’ve understood it correct). For now I focus on the GPS approaches :)

This one is interesting. As part-NCO is not in force in Sweden yet, there is a national document with RNAV regulation. The whole text about about approches is “To be published later”. I actually called the Swedish Authority last week to ask about this and the (tentative) answer I got is that the operational aspects of GPS (or PBN, really) approaches are unregulated – which would essentially mean that you could fly such approaches without any special training or approval. He did say there are airworthiness requirements, although the legislative basis for that is not clear to me. The guy I talked to primarily worked with CAT and wasn’t 100% certain about the GA situation, but he gave me the name of another person working with GA. I’ll call him the coming week.

I’ll be back!

The TSO C145/146 WAAS GPS is designed to be able to fly the following APV’s using the WAAS for official vertical guidance:

1) LPV when LPV is annunciated
2) LNAV/VNAV when LPV or L/VNAV is annunciated (Note, you do not need Baro VNAV to fly LNAV/VNAV procedures with a TSO c145/146 WAAS GPS if the annunciations L/VNAV is displayed). The LNAV/VNAV approach flown with a WAAS GPS is not restricted by the Baro-VNAV temperature restrictions, but obviously to fly the procedure using SBAS for the vertical, you must be receiving the SBAS (WAAS or EGNOS) with suitable integrity.

At the latest versions of the software or TSO also support advisory vertical guidance (not official vertical guidance) on the following procedure types:
1) LNAV when LNAV+V is annunciated
2) LP when LP+V is annunciated (Note the G1000 does not support this approach type) There are probably none or only a few of these outside the US. This procedure is sort of equivalent to a localizer only procedure and only used when an LPV is not suitable.

Any downgrade of the approach will occur at 1 minute to reaching the FAF and is always to LNAV without any vertical guidance of any sort.

Approaches that don’t qualify for any vertical guidance will annunciate LNAV and may be flown by a WAAS or TSO C129 approach GPS.

Support for the LNAV/VNAV was largely an accommodation in the US for vertical guidance early on in the program as there were many approaches that had LNAV/VNAV procedures for Baro-VNAV aircraft and almost no LPV. Now LPV is everywhere in the US and the relevance of having the capability is largely gone. I explaining to students they don’t need to worry about them, if they come across one, just fly it like an LPV.