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Descent profile accuracy


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After having flown a few sectors now with the 319 on P3Dv4.5, I am starting to notice issues with the ability of the aircraft to maintain a good level of accuracy in the descent profile. As you know, there are usually a few altitude/level constraints during the descent and on a STAR.

I find the aircraft does not always meet those constraints very well. Sometimes it is up to 500 feet too high crossing a waypoint with an active "at or below" constraint.

On other occasions, although the beginning of the descent goes well and the aircraft seems to be on profile (green ball centered), then all of a sudden, the green ball goes up and the aircraft almost levels off with nothing having changed...then, it will go down quickly and the aircraft will be very high on the profile (a bit of a roller coaster effect).

What also actually happened to me once was that after a At or Below constraint, the aircraft almost levelled off instead of continuing the descent. If I had not continued the descent myself, then I would have arrived over the FAP 15000 feet too high.

You get the drift overall.... the "VNAV" or "descent" function is erratic at the best of times. It is very frustrating as sometimes, the aircraft is too high, sometimes it is too low. Descent planning, and execution, is not reliable.

I use Active Sky for the weather and load up the wind data forecast into the aircraft FMS.   


I like the aircraft and am not looking for perfection, far from it. I just feel that a working and usable VNAV (or whatever the Airbus term is) would be amazing.


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  • Aerosoft

It's known that the current VNAV implementation has some limitation especially with more complex altitude and speed restrictions included on the STAR procedure. We would definitely like to review the VNAV at some point and improve it but it's extremely complex task. We'll see what we can do.

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  • 7 months later...

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