TBM 930 TBM 930 Coupled VNAV Non-Functional

[RandallR 451]

I have been unable to get coupled VNAV to function at all in the TBM 930 since the AAU1 update.  In its previous modded state w/the WT g3000 mod it gave an excellent indication of the descent rate and indicated the next step in altitude.  It also indicated the TOD.  None of this was coupled to the AP in that iteration so I was really looking forward to this update.

It's obvious that coupled VNAV is working for some. thecorporatepilotdad YT video on using VNAV for descent control in an ILS approach showed that it was operational, at least for him, so it must be something that I'm doing incorrectly?  I have set up in the following manner:

• Set the altitude of the FAF in the PFD
• Verified that the proper procedure is loaded in the g3000 and the proper altitudes are assigned to each fix
• Enabled VNAV in the GTC
• Enabled VNAV in the AP

I get nothing.  Sometimes a "PATH" indicator comes on in the PFD but no TOD appears on the MFD map now and the AP will not initiate (nor indicate) a descent.  Any ideas?

 

[edpatino 1,985]

I don't have any issues with the VNV system in the TBM 930 after AAU1. The G3000 avionics now have greatly improved.

I would recommend to take a look at some useful videos posted in YouTube. It's far easier this way, but sometimes it'll get a little bit tricky.

Edited March 8, 2023 by edpatino

[ryanbatc 13,103]

VNAV isn't for instrument approaches.  That's what APR mode is for (yes even rnav with vertical mins).  EDIT:  I guess I should add that you could use VNAV during an RNAV(GPS) approach without vertical mins (the approach plate would say something like LNAV near the minimum section) - attaching pic - with VNAV during an approach with lnav mins you still need to make sure you don't descend underneath the waypoint altitudes.  With LPV mins (you should be using APR mode for this) you CAN follow the vertical glide path (called glideslope during ils approaches).  But again with lpv minimums you will not use VNV and instead use APR mode if flying on AP.

VNAV is typically for STARS, SIDS or just general efficient descents.

See at the bottom of this chart it says LNAV MDA 1040 etc.  If your plane wasn't equipped with a GPS with WAAS you'd have to fly to those minimums which are typically higher.... and you COULD use VNV mode as an advisory glide path.... but you MUST meet the crossing restriction altitudes on the approach plate.

rnav by Ryan Butterworth, on Flickr

Edited March 8, 2023 by ryanbatc

[RandallR 451]

32 minutes ago, edpatino said:

I would recommend to take a look at some useful videos posted in YouTube. It's far easier this way, but sometimes it'll get a little bit tricky.

There are no videos posted on YouTube on VNAV procedures after the AAU1 Update except for the quick demo by  thecorporatepilotdad.  His video demos how the new VNAV can be used with an ILS to step to the FAF.  What I was looking for was procedures with the new coupled VNAV system, except he does not actually demo the setup. 

[RandallR 451]

37 minutes ago, ryanbatc said:

VNAV isn't for instrument approaches.  That's what APR mode is for

I am a former RW pilot and understand how approaches work (the YouTube video was demoing how VNAV could be used in combination with an ILS approach to automatically step-down to the FAF before initiating the actual approach sequence on the LOC).

No, my problem is I can't get the new coupled VNAV to work at all for standard descent control.  Since others are not having this issue I would like to know what your setup procedures are, in case I'm missing something.

And no... I am running no mods except for Seasons...

[edpatino 1,985]

8 minutes ago, RandallR said:

There are no videos posted on YouTube on VNAV procedures after the AAU1 Update except for the quick demo by  thecorporatepilotdad.  His video demos how the new VNAV can be used with an ILS to step to the FAF.  What I was looking for was procedures with the new coupled VNAV system, except he does not actually demo the setup. 

Here's one I think it's good:

It's from just after the AAU1 update, if I'm not wrong

Edited March 8, 2023 by edpatino

[RandallR 451]

Many thanks!

[RandallR 451]

59 minutes ago, edpatino said:

Here's one I think it's good:It's from just after the AAU1 update, if I'm not wrong

Well, it's certainly informative on procedures and unlike the other video, he does go thru his VNAV setup.  However, it turns out his procedures are basically identical to mine.  Unfortunately - it works for him but not for me.

Something else is going on.  I will mention that the only mods I'm running are Navigraph and Bijan's Seasons.  I would not think that these would cause any issues...

[btacon 1,874]

2 minutes ago, RandallR said:

Something else is going on.  I will mention that the only mods I'm running are Navigraph and Bijan's Seasons.  I would not think that these would cause any issues...

Have you uninstalled and reinstalled the TBM? That might be a good first step.
-B

[JYW 2,990]

I noticed something similar after AAU1. I eventually got VNAV working fine and the only thing different I did to assure this was activating VNAV on the AP a little earlier than I had originally wanted to.    In other words, you see the TOD on the MFD, all looks good VNAV-wise in the FPL screen... if I waited until I was say 2nm from the TOD and then hit VNAV on the AP, I'd get nothing... just as you describe.   No descent scale on the PFD and the TOD would just pass on by without a descent!   I found that engaging VNAV on the AP at least 10nm from the TOD and it would engage, with the PFD descent indicator displaying and all fine and dandy.

[MattNischan 3,900]

A few things to check:

• Are you selecting the VECTORS transition for your approach? If so, you will need to have a hard altitude constraint set prior to the approach in order to receive guidance. Altitudes in the approach will not be targeted (even if the system will compute the advisory altitudes for legs) until you are in the approach segment or the approach is activated (direct to the IAF)
• Does your arrival end in a MANSEQ? Similar to the above, the system will not compute a path through the manual sequence leg, so there must be hard constraints prior to the MANSEQ

[RandallR 451]

1 hour ago, JYW said:

 I found that engaging VNAV on the AP at least 10nm from the TOD and it would engage, with the PFD descent indicator displaying and all fine and dandy.

Not the case here - I don't even get a TOD now!  Also, I always activated VNAV just a few minutes after I was established in cruise - long before the TOD.

51 minutes ago, MattNischan said:

A few things to check:

• Are you selecting the VECTORS transition for your approach?
• Does your arrival end in a MANSEQ? Similar to the above, the system will not compute a path through the manual sequence leg, so there must be hard constraints prior to the MANSEQ

Good ideas, but no, I'm not selecting vectors and none of the FPs have included a MANSEQ at this point.

1 hour ago, btacon said:

Have you uninstalled and reinstalled the TBM? That might be a good first step.
-B

I'm going to try this next - this is something I've never done but I might as well cycle it.

[tup61 1,653]

Are you sure you completely deleted any (slightly) related mods from your community folder? So every mod that has to do with the TBM, the G3000, perhaps simply remove EVERY mod temporarily. Because as you said it works perfectly fine on most computers, including mine. I do it just as you: before I descent I set the FAF altitude, enable VNAV on the AP (afaik it doesn't matter when you enable it but I usually do it within a few minutes from TOD) and down it goes all the way to the approach (were I enable APP). You should see PATH in white (armed) at the top of the PFD: if you don't, something simply is wrong. You also should see the magenta arrow on the altitude ribbon (of whatever you call that). Something must be wrong with your setup because you indeed seem to take the right steps.

Edited March 9, 2023 by tup61

[tup61 1,653]

12 hours ago, RandallR said:

Also, I always activated VNAV just a few minutes after I was established in cruise - long before the TOD.

You might want to wait with activating VNAV on the AP until closer to the expected TOD.

Come to think of it: when you say you activated VNAV, do you mean on the AP or in the system (VNAV on the Flight plan page, using the GTC)? After the AAU1 update VNAV is always on and calculated.

Do you have the flightplan view enabled on the MFD, underneath the map? If so you should see the VNAV information in the lower right corner. I get to see all VNAV information without having to do anything. (With VNAV being ON I mean it being on in the systems, not on the AP). If you don't see any VNAV information in that corner something definitely is wrong. Again, check your community folder: best things to do is to remove everything that may be related to the TBM and the G3000.

Edited March 9, 2023 by tup61

[JYW 2,990]

Certainly the incompatible mods thing can be relevent.  I flew the CJ4 yesterday and found an old cockpit textures mod for it, so tried it out.   I then found I had no autopilot modes whatsoever... from a texture mod!  

The reason was, the texture mod had modified the PFD screen and, since it changed in AAU1, the mod was using an outdated file.   It turned out, the AP itself was actually working, but there were no AP modes showing on the PFD whatsoever, as a result of the outdated mod.   I was checking my keyboard assignments, Axis & Ohs profile.... everything, to discover why the AP was 'broken' and not engaging any modes.... I then compared files between the mod and CJ4 AAU, saw the problem, removed the CJ4 Texture Mod, relaunched and there was my AP back, working perfectly again.

Had someone suggested a texture mod would prevent an AP from working, I'd have struggled to see the logic there, but there you go! 🙂

The MSFS ecosystem is amazing - but very sensitive.

Edited March 9, 2023 by JYW