Flybywire A320 VNAV

[MarkW 1,493]

I am assuming I am correct that the Flybywire sim does not have a working VNAV?  Please correct me if I am wrong here.  I have basically been manually working out the descent profile using 3:1 and descending at approx 2000 ft/min.  Any ideas when their own autopilot software will be available?

[earthdog 842]

No, VNAV is not operational yet.

I think it would be better to follow on their discord. Everybody is there and everything that you need to know.

Discord: https://discord.gg/UjzuHMU

[tweekz 2,165]

Correct. The VNAV turned out to be one of the toughest challenges. But it is in the works.

[omarsmak30 4,068]

This is an update from Benedict one of their core developer about the autopilot complete overhaul:

Quote

as mentioned above, this will be a triple-feature at the same time:
1) new autopilot (+ fbw) - AGuther is quite far on this and has done an amazing job as you can obviously tell by all the videos in #progress, but I think there is still some details to sort out, especially around switching, so the FCU and star-modes
2) new flight plan internals - holland has successfully integrated the WT flight plan manager which unlocks a lot of new features (like directs in SIDs and STARs working), but we still need some specific features like discontinuities to work better, but that's manageable. We don't have support for things like DME arcs or radials yet.
3) LNAV/HPATH - I'm working on this, and it's the bridge between both of the above (=NAV mode). It basically takes the flight plan from the new system (as a list of waypoints), and calculates the actual route the aircraft will take, and then supplies that to the autopilot. This includes things like starting turns early, and displaying the route the aircraft will take on the ND. This is in it's early days, but we have a very basic version already that can follow a straight line and account for cross wind (very similar to TRK mode). Right now it's all about flying a decent path on waypoint sequencing, and later intercepts and maybe holdings.
None of these will probably be in master without the rest, because then we'd have to make them work with the old flight plan/auto pilot system respectively.

So basically they have almost all the separate puzzles ready (custom AP, custom ATHR, custom FBW, custom FP) and now they are connecting all these puzzles together, they are almost there, just a bit of patience :).

Edited January 25, 2021 by omarsmak30

[MarkW 1,493]

Thanks for the updates.

[dresoccer4 118]

does the VNAV not work still?

[Jeff Nielsen 1,386]

26 minutes ago, dresoccer4 said:

does the VNAV not work still?

No, it does NOT.  Coming soon.

[cavaricooper 2,615]

It hasn't been vetted yet, however, with the EFB calculator and fix range circles it is quite possible to initiate a managed descent at the appropriate time.  Then if intervention to keep path is needed, I put that down to ATC and do whatever needs doing.... what FBW has done, is doing and will do is certainly gratitude inspiring, for me.

[holland786 504]

To give you guys a preview...

Here's a preview of a full VNAV approach and descent profile, including the new CDA option (which we will be the first to do, since only the Honeywell FMS supports it in real life and we are the only ones reproducing that FMS) that I am working on. This for now only shows pseudo-waypoints on the navigation display, but I can assure you a full path is computed.

 

You can see the ToD, DECEL and FLAP1 / FLAP 2 pseudo waypoints (the latter being exclusive to CDA mode) on those images.

Keep in mind that this is early code and some elements are subject to change and / or may look inaccurate.

More to come soon.

[Mike S KPDX 597]

I understand that one of the issues is the lack of being able to get winds from the sim.  The sim wx is only generated in a bubble about 45 miles in diameter.  The cloud systems that one sees on the distant horizon is just that, cloud structures based in base info from Meteo.  The real aircraft utilizes forecast winds blended with immediate current winds aloft to form that portion of the VNAV calculations, MSFS simply does not have those in sim forcasts.

However, I am not sure why distant winds can not be bi-passed by FBW and just calc based on know route requirements at fixes?  I use navdata so maybe the ingame navigation database is not robust enough to provide this info.

[Jeff Nielsen 1,386]

16 minutes ago, Mike S KPDX said:

I understand that one of the issues is the lack of being able to get winds from the sim.  The sim wx is only generated in a bubble about 45 miles in diameter.  The cloud systems that one sees on the distant horizon is just that, cloud structures based in base info from Meteo.  The real aircraft utilizes forecast winds blended with immediate current winds aloft to form that portion of the VNAV calculations, MSFS simply does not have those in sim forcasts.

However, I am not sure why distant winds can not be bi-passed by FBW and just calc based on know route requirements at fixes?  I use navdata so maybe the ingame navigation database is not robust enough to provide this info.

Basically....what are you talking about?  Why do you think these are issues or problems slowing them down?

[Mike S KPDX 597]

14 hours ago, Jeff Nielsen said:

Basically....what are you talking about?  Why do you think these are issues or problems slowing them down?

I recall reading this in the FBW Discord.

Basically, they are unable to get winds aloft data from the sim beyond about 30 miles.  Thus it must be assumed or omitted from the calculations.  Basically I hope this answers your question.

[cavaricooper 2,615]

I believe SU6 & SU7 are supposedly taking care of this and many other Wx issues, nicht?

[Jeff Nielsen 1,386]

2 hours ago, Mike S KPDX said:

I recall reading this in the FBW Discord.

Basically, they are unable to get winds aloft data from the sim beyond about 30 miles.  Thus it must be assumed or omitted from the calculations.  Basically I hope this answers your question.

Yeah, but I'd leave it to them to say if it's actually slowing them down.

[Jeff Nielsen 1,386]

16 minutes ago, cavaricooper said:

I believe SU6 & SU7 are supposedly taking care of this and many other Wx issues, nicht?

SU7 (next month), I think starts it off.  Not sure if that translates in to 3PDs being able to tap in to that data though (If they don't have those variables).