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J van E

Need a GTN 750 RNAV approach tutorial. Badly.

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Bought the GTN 750 today! Awesome device! What a load of great options it has! The ability to graphically change the flightplan is great! Nice to see that Europe also has safetaxi now! It's also great that you get a preview of the approaches and the various IAF point: makes it very easy to pick the right one on the fly! Loving it! Specially glad I could turn of that utterly annoying clicksound!!!!!!! :wink: I was quite sceptical at first but now I have it I can't imagine doing without it! Yes, you were all right about this GTN!  :wink:

 

Anyway, although things went quite okay with the GTN in my RealAir Legacy (apart from accidently clicking the OBS button and not being able to get back on track) I have no clue what to do when it comes to GPS approaches.

 

I tried the RNAV for RW 7 into ENML a few times but I wonder: do I need to set the AP tp APR or should I keep it on NAV...? I want to fly the approach on AP. But everytime something goes wrong with the altitude not being kept and the GS not being intercepted (it is intercepted according to the AP but the plane just dives down anyway).

 

Another thing: after waypoint ML420 (the last point before the runway) I get a message that the plan is suspended...? I can only keep it suspended or enable the missed aproach (towards ML420)? What's up with that? Does that mean I should turn off the AP and take over before that point...?

 

(See the chart here: https://www.ippc.no/norway_aip/current/aip/ad/enml/EN_AD_2_ENML_5-5_en.pdf?cachebust0615 BTW If you want charts for Norway, check that site https://www.ippc.no/norway_aip/current/main_en.html It is awesome and very easy to use!!!)

 

I wonder if someone knows a good GPS approach tutorial: I watched a few video's on YouTube but none of those clearly explained how it works.

 

Another question: you can set various setting using the Flight1 config tool: amongst others Link CRS and auto CRS. What is the most realistic setting for these? Should I link them or not and should it be Auto or not? Auto doesn't seem realistic to me but I am not sure about the Link... I suppose all settings you can change within the GNT itself are 'realistic' otherwise the options wouldn't be there (like auto change between GPS and NAV) but I am not sure about the Flight1 options.

 

Final question: when I start a flight the popup of the GTN is there by default and so I have to click it away every time. Is there a way to have that popup NOT popup by default? Although it can be nice to have it when needed I prefer to not use it and I want it gone whenever I start a flight.

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Part 2.

 

It seems that 1. the kind of RNAV approach I get in Norway doesn't have vertical guidance...? Although I do see a glideslope in the HSI I suppose that is advisory only and I have to take care of it myself? Seems I should not enable APR on the AP but keep it in NAV and control the alt manually (by AP or not). And the point where I get the SUSPENDED message is the DH so from there on I either have to do a missed approach or stay suspended and take over manually altogether. So I guess you ALWAYS land in suspended mode. If you do get an LPV approach, should you enable APR or still not?

 

Am I a bit right with all this?

 

BTW I also really love the terrain mode and TAWS! Very relaxing to have that when flying near mountains in the mist! I also like how you can change the corner fields of the Map to your liking. The VCALC seems promising too but I didn't seem to get the message. I did disable all the airspace warnings, including OTHER: does this also surpress the VCALC messages maybe...?

 

Flying the approach into ENSD just now was awesome with the GTN 750 and the right approach plates from www.ippc.no The approach lets you come in at an angle due to all the mountains around the airport and without all this I probably would have messed up the approach completely. But now I could fly it without a single TAWS warning. Great stuff. I picked the approach (RWY 9) and the IAF when I got near and doing all that is extremely easy and done within no time. Activating the approach also worked flawlessly. (My problems with that were probably due to clicking on OBS by accident, as I posted earlier).

 

Anyway, GREAT STUFF! Thanks to everyone who talked me into buying the GTN 750! :smile:

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The procedure you linked to is just an LP approach without vertical guidance (LP-GNSS) (LNAV) meaning you should stay in GPS mode and use v/s. On the chart it has recommended v/s and speed guidance.

 

You use NAV when you use VOR or ILS and tune the navigation radios accordingly. Intercepting glidepath with approachmode

 

 

 

 

Michael Moe

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Ok, thanks. I know see that LNAV at the bottom of the chart... When I do get an LPV approach (which probably won't happen anytime soon in Norway), do I use APR in that case (with GPS still enabled)? Or does APR never ever work with GPS, not even with an LPV approach?

 

P.S. After reading the relevant part of the Flight1 manual I think I can conclude that Link CRS is realistic but that Auto CRS isn't. Correct?

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LPV is just a GPS version of an ILS, in which case, yes, you will use APR Mode. Anything with vertical guidance LPV, LNAV+V, LNAV/VNAV can all use APR mode. 

 

With regards to your question about suspend, when flying an approach, the GPS will "suspend" the approach after reaching its final waypoint. Since the GPS assumes you will see the runway and land, it stops providing guidance. Pressing the OBS button will sequence the missed approach. The missed approach is usually done initially with the autopilot off until stabilized in a climb.

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LPV is just a GPS version of an ILS, in which case, yes, you will use APR Mode. Anything with vertical guidance LPV, LNAV+V, LNAV/VNAV can all use APR mode.

 

With regards to your question about suspend, when flying an approach, the GPS will "suspend" the approach after reaching its final waypoint. Since the GPS assumes you will see the runway and land, it stops providing guidance. Pressing the OBS button will sequence the missed approach. The missed approach is usually done initially with the autopilot off until stabilized in a climb.

The GTN will only vertically couple to the autopilot with LPV minimums. I'm not positive if this is how the real unit operates.

 

Edit: looks like the real one can vertically couple to approaches with all those types of minimums. Hmm mine won't do that in P3D.

 

Check out the Bruce Air GTN tutorial JvE

 

 

https://onedrive.live.com/view.aspx?resid=110AA5B593D58477!8858&app=WordPdf

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Re AutoCRS... it depends on the HSI gauge..

 

If it is part of a glass gauge, like a G600, AutoCRS is realistic..

 

If it is a mechanical HSI like the Duke, you would be required to set

it by hand... but you can cheat and set it to AutoCRS to save you some work.. :wink:

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I'm having a tough time finding an approach with vertical guidance that isn't an LPV... There used to be a bunch

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Thanks for the help, everyone! I now know how to do a GPS bases approach. ;) That tutorial link was nice, thanks Ryan, and it was specially nice because it confirmed my own findings (like not using Vectors but always choose the intersection that's in your direction). I can do quite a nice approach now even on AP using the altitudes from the charts for the various waypoints of the approach. I also totally understand the suspended message now.

 

Thanks for the info on the Auto CRS option, Bert. I decided to turn it off: gives me something nice to do during the flight. (Flying the RealAir Legacy only now!)

 

I just finished a really awesome night flight over mountains and lots of clouds: no problem thanks to the terrain option and also thanks to flying according to the charts. I used the graphical edit option to make sure my take off would be okay (avoiding mountains) with the information from a departure chart: I simply had to drag the path to an NDB and it was done! Great stuff. And I had a perfect LNAV approach. Norway is a great place to fly with charts and the GTN due to all the mountains around.

 

Yesssssss, in case you didn't notice: I am having BIG FUN with all this! ;)

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That approach into rwy 7 ENML should have given you vertical guidance up to ML409 (the MAP), it's an LNAV+V, when you see the glidepath indicator active yes, just click the APPR button and leave the CDI source on GPS. You'll lose all guidance at the MAP though and in this case it's a long ways from the runway so you'll have to take over manually at that point. The "remain suspended" dialog will go away when you slow down to about 30 kts on the runway, it figures at that point you've either landed successfully or crashed and in either case won't be needing the missed approach :smile:

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From this link there should be 3488 procedures and over 1000 airports.(in theory)

 

 

https://www.faa.gov/about/office_org/headquarters_offices/ato/service_units/techops/navservices/gnss/approaches/.

 

Check the Excel file LNAV/VNAV

 

 

Michael Moe

 

 

Shweet, thanks. Though some of them do have LNAV/VNAV, They are shared with LPV. The garmin will go to the highest approach setting available. 

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That approach into rwy 7 ENML should have given you vertical guidance up to ML409 (the MAP), it's an LNAV+V, when you see the glidepath indicator active yes, just click the APPR button and leave the CDI source on GPS. You'll lose all guidance at the MAP though and in this case it's a long ways from the runway so you'll have to take over manually at that point. The "remain suspended" dialog will go away when you slow down to about 30 kts on the runway, it figures at that point you've either landed successfully or crashed and in either case won't be needing the missed approach :smile:

Haha LOL Yes, it is a smart device. ;) Good to know btw that I can ignore that suspended message. I thought it was mandatory to click on one of the two options.

 

Ok, so whenever I do get vertical guidance I have to wait with enabling APR until the GS is active on the HSI. I shouldn't not arm it long before that like with an ILS. And I have to take full control at the MAP point. Got it.

 

I wonder how you know it's LNAV+V...? Because the chart only shows LNAV...?

 

https://www.ippc.no/norway_aip/current/aip/ad/enml/EN_AD_2_ENML_5-5_en.pdf?cachebust0615

 

But maybe the GTN shows that +V. I will watch for that the next time I select an approach.

 

Something else: is there a way to make the transponder default to 7000 instead of 1200 for VFR? I only fly in Europe/Norway where 7000 is default. Maybe I can edit some cfg somewhere to get this done?

 

And finally (for now, haha): whenever I press and hold the Home button to go straight to the map I get a message after a minute or so that the Home button is stuck... I have to click the Home button and the message is gone. Seems like a little bug to me...? Happens everytime. For now I don't use that option anymore.

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I wonder how you know it's LNAV+V...? Because the chart only shows LNAV...?

 

https://www.ippc.no/norway_aip/current/aip/ad/enml/EN_AD_2_ENML_5-5_en.pdf?cachebust0615

 

But maybe the GTN shows that +V. I will watch for that the next time I select an approach.

 

Yes that's shown in the GTN and I don't know if they really give you vertical in the real world but they do in the sim. You'll see "TERM" switch over to "LNAV+V" or "LPV" (in green text) along the bottom of the GTN unit when GS becomes available, should be able to click the APPR button anytime after that.

 

 

And finally (for now, haha): whenever I press and hold the Home button to go straight to the map I get a message after a minute or so that the Home button is stuck... I have to click the Home button and the message is gone. Seems like a little bug to me...? Happens everytime. For now I don't use that option anymore.

 

That's a bug in the GTN Trainer itself at v5.13. Garmin will need to fix it, hopefully in the next version.

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Ok, thanks, Jim! I will keep a close eye on TERM the next time! ;) And good to know it is a bug indeed and not something wrong on my end.

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anyone up for a flight from GUC to APA on vatsim? Headed to GUC right now in the duke. Looking for some bad weather flying.

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In the meantime I am having a lot of fun with the GTN. This evening I flew into ENSN and oddly enough there were no approaches AT ALL in the GTN while my database is from last december and the approach plates were from may 2015. Even a few waypoints couldn't be found at all!!! Very strange. But... no problem with the GNT 750! I simply looked where the two main waypoints of the approach were located and added them as temporary user waypoints! Graphically changed the flightpath and done! Worked like a charm! Big fun! :smile:

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Could someone please confirm what nav data the GTN750 uses? I can't see it on navigraph

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Could someone please confirm what nav data the GTN750 uses? I can't see it on navigraph

It uses the navdata from the Garmin PC Trainer Lite that it is required when you install Flight1 GTN series.

As far as I am concerned, navigraph air cycles would not work on this.

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Correct. Navigraph and similar data doesn't work with the GTN 750. Unfortunately. It's almost odd no one has been able to get it working...? But I suppose that's because of legal stuff.

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I am discovering new nice little options all the time. This evening I discovered that the trip timer, which I have placed in the lower right corner of the map (which on its own is an awesome feature) can be set to launch 'In air'! By default it is set to start at engine start but having it start counting as soon as I have taken off is GREAT!

 

The GTN 750 is one of my best flightsim purchases ever. What a joy. (Even though I don't have charts in Norway but that's no problem because my iPad is far more convenient for that!).

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Try VCALC too Jeroen, when your chart says you need to be at 5,000' crossing a given waypoint for example you can enter 5000' at 0nm from [a waypoint in your FP] and a msg will pop up when it's time to start down. Also you can select "vertical speed required" as one of your user data fields and it'll show you the FPM value needed to arrive at that waypoint at the selected altitude. VCALC is on the Utilities page.

 

Jim

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Thanks for the tip, Jim! I already had a look at VCALC and tried it once but forgot about it later on in the flight. ;) I didn't know though about the vertical required speed being an option for a user field: I will certainly try that! Choosing the right time to start a descent (and figuring out the right vertical speed) is one of my weak points so the coming flights I will certainly test this!

 

Those user fields are great: pity there are only 4. ;) I think I will swap my current wind field with this required vertical speed one because this one I can actually use! And my trip timer might perhaps run just as well in the background so I will have another look for that corner in the extremely long list of possible options. If someone has another great tip for this, let me know! (My other fields are ground speed, which I will certainly keep, and distance to the next waypoint, which I will also certainly keep).

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