The last couple of days i seem to be arriving on final at least over 2k  or more higher than i should be in V Nav. is anyone else experiancing this? The only thought i have is  i am on the Beta for the updates mainly to the A310. Could it be a cause ? I don't know. It seems strange to have been perfect for months, yet suddenly this has started happening .

The PMDG 737's are fine, so i am at a loss.

Edited November 25, 20223 yr by Car147

Have you downloaded the wind forecast into the MCDU? My VNAV with the Fenix is pretty spot on!

17 minutes ago, Silicus said:

Have you downloaded the wind forecast into the MCDU? My VNAV with the Fenix is pretty spot on!

Yup, everything set as per instructions. Approach etc set up in time for TOD, Metar grabbed and inputed. I just cannot understand it, it's operated fine since launch.  What i have noticed is at some point in the descent, usually below 10k it will start dropping  to only hunfreds of ft per min, instead of the usual !500-2k depending on the route etc.

The thing that's really throwing me is the PMDG aircraft don't have the issue. I'll need to try the FBW A320 and see what happens there.

Thanks

2 minutes ago, Car147 said:

Yup, everything set as per instructions. Approach etc set up in time for TOD, Metar grabbed and inputed. I just cannot understand it, it's operated fine since launch.  What i have noticed is at some point in the descent, usually below 10k it will start dropping  to only hunfreds of ft per min, instead of the usual !500-2k depending on the route etc.

The thing that's really throwing me is the PMDG aircraft don't have the issue. I'll need to try the FBW A320 and see what happens there.

Thanks

How well are you managing your speed? Under 10k what do the constraints look like? 

The airplane will struggle to hit a VNAV path if you're descending at a high IAS and not managing speed with judicious application of speedbrake, the A320 keeps its speed up in descent. Also, if you had no restrictions under 10k and were just descending to a point on the approach, it's going to match the VS to hit whatever is the next restriction in the box - if it's 30 flying miles and 4k feet, you're going to see a really slow descent rate.

Need more details to determine if WAD or an issue.

I have always just let it do it's thing, and never had an issue.I do use speed brake, but only if i see the IAS getting near the upper limit. I have also noticed the green dot dropping to the bottom of the graph, Which i always thought means the aircraft is too high. yet there's not the increase in descent to compensate for it. Before this it would increase the descent to bring it back into line.

 

Thanks @mspencer

 

Edited November 25, 20223 yr by Car147

User error 😋

The green dot is your path, it's going to try to chase your path, but only inside the speed window indicated on the PFD if you are in managed speed. If in selected, it will follow the window input.

Airbus is pretty slippery on the way down - if your CI is commanding 310/320 after the mach changeover, have your hand on the speedbrake because you will be deploying it often. Once you get a hang of it, it's really easy to manage!

Just think of it as managing your descent rate and drag to match up the two numbers. Since you're in a descent, thrust isn't your primary concern, drag is, especially because the airplane doesn't like to slow down.

Ok< i did notice it's been a lot faster in the descent compared to earlier versions. I'll try another flight tomorrow. Thanks for the info @mspencer