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ALT capturing bounce


bpcw001

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Hi,

on autoflight (managed or selected, doesn't matter), when capturing the selected level/altitude, the aircraft "bounces" up when the altitude is captured with a V/S lower than 1000fpm.

Example:

You're climbing at 800fpm. When then altitude reaches the range were the FMA announces the capture of the target alt, the aircraft will violently pull up to a V/S equal or greater than 1000fpm first before settling for a lower V/S to finally capture the target alt.

If the climb speed is >= 1000fpm right away, this effect is not there.

I run Hotfix 1.01c.

Any ideas? I thought I read somewhere that this problem was supposed to be fixed.

Thanks

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Ah, I was speaking too soon!

I just experienced it with the A319 CFM model in managed climb to FL370.

Aircraft was climbing at 800fpm when during capturing it bounced up to 1300fpm only to slowly roll back V/S to level off at FL370.

Sorry, but this doesn't seem to be solved yet. Never had this with the IAE model.

Hope this is still being read despite the thread being marked as answered.

Thanks

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It's a problem also had the old AXE: when you're levelling off at low V/S (around or less than 1000ft/min) the aircraft rapidly increases its V/S up to 1700ft/min to capture the ALT set on the FCU. Weather or not, in my case it's the same

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Well, I did some more flying. After hotfix 1.02 I get this behavior with CFM and IAE A319 models.

It *only* happens when in managed climb.

Please try the following:

Set up a heavily loaded aircraft and let it climb in fully managed mode to a high flight level, so that before capturing the target level, it will only climb at a V/S < 1000fpm.

I noticed that when the capturing kicks in, the aircraft bounces up to 1500fpm to then finally settle for lower V/S to finish capturing the target level.

I can get this effect consistently.

My weather program is Active Sky Next.

Selected climb with dialed-in V/S does not yield this behavior, and that's what I use to mitigate this effect for passengers :-)

Open Climb I haven't tried yet.

Thanks

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So, yes, it also happens when ASN is *not* running (nor any other weather program, just FSX).

But the following detail might be interesting for recreating the situation:

I had the cruise level set up as FL360 in the MCDU. During managed climb, I put FL340 in the FCU and let it level there. The bounce did *not* happen.

When turning in FL360 in the FCU and pushing the button for managed climb, it would climb to the MCDU-set cruise alt (FL360) and there it did bounce before leveling off!

It appears that the bounce only happens when finally leveling off at the cruise level set in the MCDU.

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Just tried with a freshly installed 1.1 version, installed according to the official upgrade guide.

Issue is still present. No weather program used, just FSX.

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Installed v1.10 today and made a flight LIRN - LGKF. Climbing to FL370 RoC above FL340 was 900-1000 fpm. At arround FL365 RoC increased quickly to 1500+ fpm and then slowly reduced until FL370 was reached. This was happening randomly with previous version, but not in every flight. Using ASN SP1.

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Hello Mathijs,

I can confer that I have seen this behaviour today as well. Airbus 319 CFM climbing to 34k gets to about 33.5k then the climb rate shoots up to 1700fpm to settle the cruise height.

This issue was also present in the AXE .

Bus v1.10 was installed as per the instructions given, and on a clean FSX install, happen with/without weather engine have got both ASN/Opus.

Regards

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Hello Mathijs,

I can confer that I have seen this behaviour today as well. Airbus 319 CFM climbing to 34k gets to about 33.5k then the climb rate shoots up to 1700fpm to settle the cruise height.

This issue was also present in the AXE .

Bus v1.10 was installed as per the instructions given, and on a clean FSX install, happen with/without weather engine have got both ASN/Opus.

Regards

Yeah, 1700fpm is the number I get too. It doesn't do this when the climb is with a V/S > 1700fpm anyway, but when lower (all managed mode), it shoots up to 1700fpm before settling.

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  • 2 weeks later...

I can confirm the same issue, both IAE and CFM aircraft pitch up ~300ft before the cruise altitude is reached, Im using FSGRW for weather.

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