Haversine Forums -> AirTrack - General Issues and Support

FMS LNAV had never worked correctly.

Posted on April 2, 2012 17:03 by ming010

Thanks for this great app.

I've tried couple times on both Cessna 172 or default B738.
The LNAV function never worked. And it just turned to heading 360 every time I pressed the bottom.
Is there any tips to operate it on default aircraft to simulate GPS navigation?

Posted on April 19, 2012 17:30 by FlyIce

If you're using FSX then I have the same problem. If I choose Source = FMC, LNAV just steers the plane to 360, if SRC = NAV, then it appears LNAV works like VOR Loc.

Anyway, by reading the manual, it seems to me that Airtrack's FMC actualy does not work with FSX at all? If so, will it work in the future updates? If not, then how we can get FMC to steer the plane in FSX? IP Team's response will be greatly appreciated.

Overall, I really like this app, and it will be a truly great one once it gets polished a little more.

Posted on April 20, 2012 00:57 by haversine

Hi both,

Sorry dor the delay;

Indeed AirTrack does not totally control FSX in terms of auto-pilot I'm afraid. Most things work, and it does change a few AP bits like heading dial or speed dial, but other things in the AP may not work.

The Source = FMC has no effect on FSX; it only acts on X-Plane and is used by the app itself internally. So if you switch to FMC, the app itself will work in FMC mode and provide you all the FMC guidance it can, but this will not be propagated to FSX.

Likewise if you enter a flight plan in AirTrack, AirTrack will follow and report on it just fine, but this will not be propagated to FSX. In order to have both in sync you have to enter the exact same flight plan in FSX independently and activate LNAV there.

As for the future, the problem seems to be that the standard FS9/FSX API doesn't allow FMC/flight plan related changes to be made that easily by external apps and that as a consequence each plane implements a flight plan / FMC in its own independent way, which makes it impossible for one app to be compatible and work with all the different planes and implementations that exist in FSX. This and FSX being relatively old and abandoned by Microsoft doesn't give us much hope :(

Having said that, we'll be working on a new communications protocol so we'll try to make as many things work as possible, but as I said, the lack of a standard API and the lack of support for the flight sim itself is making things difficult. So we'll see...

kind regards,
joao @ airtrack team

Posted on April 28, 2012 02:07 by FlyIce

Thanks for the reply, Joao.

I found that AirTrack one way download of flight plane from FSX is already very useful. I've been enjoying Airtack more and more and I now always fly with it.

Posted on January 6, 2015 22:35 by MikeOscar

Hi there

I just faced the same problem and must say that I'm a little bit disappointed by this fact, which in my opinion, at least for FSX users, significantly reduces the usability of this otherwise excellent app.

To be not only complaining, I'd like to make a suggestion for an FSX-specific workaround, which also has been used by Alex Wemmer for his vasFMC software:

In both the HDG SEL and the LNAV modes, the vasFMC software writes the actually desired heading to the FSX HDG SEL variable. This means that the FSX autopilot must be set to HDG SEL in both cases, which is the only small drawback of this otherwise elegant solution to the FSX-specific LNAV limitations for external applications. The actual behavior of the plane reflects exactly what one would expect from FMC sourced LNAV mode.

As far as I can judge, this could also be a feasible solution for the AirTrack app. Any feedback from the AirTrack team would be very much appreciated.

Best regards,

Posted on January 11, 2015 21:28 by haversine

Hi Marc,

This is indeed a good idea and I think it's feasible. The only thing is that it would have to adjust the heading as it moved along to ensure the track is constant to LNAV (to compensate for cross-winds etc ) but should be feasible.

I'll add it to the wish list and try to implement it.

thanks for the suggestion,

Posted on January 13, 2015 18:40 by MikeOscar

Hi Joao,

Well that's excellent news, thank you for considering implementing my suggested workaround!

Is there any way I can get notified automatically about new releases?


Posted on January 25, 2015 12:18 by haversine

Sorry for the delay,

Best way to get notified about new releases is Facebook I guess as whenever there is a new version something gets posted and propagated :)

Note: You need to be logged in to post in the forums.

© 2023 Haversine