LNAV/VNAV (not LPV) approach capability after legacy G1000 upgrade

[Timbot]

Hi all..

A question for those that have upgraded their legacy G1000's to GIA63w's..

Background.. in Australia we have no WAAS/SBAS. Yet. We will have it within 5 years though.

To meet an ICAO mandate for vertically guided approaches everywhere, Australia implemented LNAV/VNAV minima to pretty much every aerodrome in the country. In the absence of WAAS this minima has only been available to Baro VNAV capable aircraft (i.e. boeings/airbus/atr/proline kingairs)

When SBAS is switched on here, in theory we should now be able to fly these LNAV/VNAV procedures with the vertical path derived from the SBAS signal.

We are unlikely to have LPV procedures any time soon.

Has anyone that has done the Gia63W upgrade comment on flying a procedure where you only have LNAV and LNAV/VNAV minima? (I.e. no LPV)

Do you actually get proper VNAV guidance (not LNAV +V !!!)

I'm trying to ascertain that this actually works after the GIA63w upgrade, and that there aren't any weird garmin/mooney software issues..

Tim

[carusoam]

Standby Tim...

There are a few MSers that have gone through the long awaited, expensive, upgrade that will have some positive news to report...

i don’t remember enough detail accurately to report the details...

Good luck with getting procedures in place.

Best regards,

-a-

[PaulM]

(Snip first draft... since I had never seen an L/VNAV annunciation).  

190-00647-03 Rev. A.. page 238: "The G1000 WAAS GPS allows for flying LNAV, LNAV/VNAV, and LPV approaches according to the published chart"

On the G1000 in SBAS coverage There is: "L/VNAV GPS approach using published LNAV/VNAV minima".  but I have never seen that, since if there is also LPV available, you get the LPV indication and you can use any of the minima.    I usually only have LNAV+V, LPV or LP+V

So as soon as SABS is available you will have the LNAV+V available for all approaches and probably L/VNAV available for others (If that is coded in the database)., 

https://www.casa.gov.au/airspace/navigation-requirements  has a bunch of text.. some Baro-VNAV only.. others:

"RNAV non-precision instrument approach procedures (NPA) and approach procedure with vertical guidance (APV) – RNP APCH (still titled 'RNAV GNSS' on Australian approach charts), with LNAV or LNAV/VNAV landing minima."

Where the FAA AC 90-107 section 4n. has:

https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC 90-107.pdf

n. Lateral Navigation/Vertical Navigation (LNAV/VNAV). An RNAV function that computes, displays, and provides both horizontal and approved vertical approach navigation. Both WAAS vertical guidance and baro-VNAV support approaches to LNAV/VNAV lines of minima.

Good luck, and I'm sure that when SBAS is in place they will clarify the policy, and add LPV approaches.  I can't see that the database isn't all coded the same, so they should show up on the G1000 as L/VNAV, but perhaps you can check with Jepp on that. 

I will look for a L/VNAV only approach somewhere near me and see If can can tell you.

Edited February 29, 2020 by PaulM

[Timbot]

3 minutes ago, PaulM said:

So as soon as SABS is available you will have the LNAV+V available for all approaches and probably L/VNAV available for others (If that is coded in the database).

Thanks Paul, we get the advisory only vertical path (LNAV+V) already (when flying with a WAAS navigator like a GTN650 or 430W/530W)

Coding of LPV requires a FAS data block so the nav DB side is somewhat different from the LNAV/VNAV implementation.

 

[PaulM]

Interesting,  are those GTNs and GNS receiving the "D" signal?   

 I will disable SBAS the next  time I'm up and see If I still have LNAV+V.. 

I was going through the FAA ARINC database, and it is a mess, and nobody gives away the decoder book for free. 

Here is a LPV and LNAV/VNAV coding near me.. 

SUSAP KMSVK6FR15   R      020TOLMYK6PC2WALPV       ALNAV/VNAV ALNAV                                                   JS   573001310

So I can find LNAV/VNAV without LPV.. only 62 in the FAA database. 

SUSAP KLGAK6FR31-Y R      020MANLLK6PC2WN          ALNAV/VNAV ALNAV                                                   PS   327311903

I found KLGA RNAV 31 Y... that is close enough that it should load as an approach.. can't fly it, but let's see if it gives the right annunciation, I can get in the terminal area if required. 

 

[Nick Pilotte]

@Deb  Deb and David have been filling me with TONS of G1000 info and I really appreciate it.  They mAy have some insight as they were a valuable resource for be as a couple who have “been there, done that” in upgrading their G1000 Ovation.  

[GeeBee]

Upgraded mine. No reason why you cannot fly an approved LNAV/ VNAV procedure with SBAS. Not only is the guidance solid, my S-tec flies the GP really nicely.

 

[midlifeflyer]

Dunno about the connection to any specific unit but modern GPS navigators, including the GNS-W units definitely annunciate and fly LNAV/VNAV approaches. I recently tested them on some of the manufacturer trainers and confirmed with pilots who have flown them for real. Here's a sample from the 530W. It's the RNAV (GPS) Y Rwy 21L approach into Atlanta's PDK airport, showing both lateral and vertical guidance.

[Deb]

Thanks Nick, you’re too kind. 

We ran Mark’s (@midlifeflyer) example of the RNAV (GPS) Y RWY 21L at KPDK on the G1000 PC simulator (v14.01). This approach has LNAV/VNAV, LNAV and circling minimums (minima?); there is no LPV.

It annunciated terminal (TERM) mode outside LOGEC; it annunciated L/VNAV from LOGEC to KOVEY

and continued to follow the glide path past KOVEY

[midlifeflyer]

1 hour ago, Deb said:

Thanks Nick, you’re too kind. 

We ran Mark’s (@midlifeflyer) example of the RNAV (GPS) Y RWY 21L at KPDK on the G1000 PC simulator (v14.01). This approach has LNAV/VNAV, LNAV and circling minimums (minima?); there is no LPV.

 

It annunciated terminal (TERM) mode outside LOGEC; it annunciated L/VNAV from LOGEC to KOVEY

 

and continued to follow the glide path past KOVEY

 

Yup. That's what it should do.

The reason I looked into it: Since LNAV/VNAV was originally a vertical path based on a Baro-VNAV system primarily used by airlines, there is a lot of confusion out there about it, with many thinking you must have a Baro-VNAV system in order to do it. But the manuals contain language indicating it is authorized for use based on WAAS. So does the AIM, which contains the following:

Properly certified WAAS receivers will be able to fly to LPV minima and LNAV/VNAV minima, using a WAAS electronic glide path, which eliminates the errors that can be introduced by using Barometric altimetry..