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Vertical Speed TOC


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Guys

 

I've been noticing that as the aircraft reaches within 200ft of top of climb in managed mode, the VSI suddenly increase from around 200-300fpm to 1500fpm then drops back down to 200-300fpm when within 100ft of top of climb.  I have observed this on the 319/320 CFM versions.  No big deal but wondering if this is correct.


Thanks and regards

 

Ken

 

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I've experienced this on the IAE versions as well.  Doesn't always seem to happen, so I haven't quite figured out how (if possible) to prevent it myself other than that It seems to happen at the initiation of the ALT* vertical mode.

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It's actually usual in the real aircraft for the vertical speed to increase when reaching top of climb. I have always found it a bit odd. It never goes as much at 1500ft/min but it does usually increase from, say, 300ft/min (after it's been struggling to get up there for the last 5 minutes) to 800ft/min for the last hundred or so feet.

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Ok, as long as its normal.  I would say 1500fpm is the spike although I don't believe the aircraft is actually achieving that for the last 200 or so feet.

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Mmmmh, thats weird... I personally do not have this issue! When approaching my cruising altitude the engines gently spool down and the aircraft lowers the nose! 

Without criticizing you, are you sure that you have Autothrust active? Would be great, to get some pictures of the ECAMs, the FCU and the PFD, when this occurs!

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Hi,

 

i know Boeing pilots (or company procedures?) which for the last 2000 ft before reaching TOC, change from VNAV to VS and decrease the actual rate step by step to 1500 then 1000 then 500 then 200, perhaps prevent to this effect and overshoot the selected FL.

 

 

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It never overshoots the selected FL, at least not for me.  It just spikes at the initiation of the ALT* mode and then quickly decays back to something more reasonable and then level flight.  There is also no engine spool-up.  Just a little hiccup in pitch barely enough to affect airspeed, really (like a bump of turbulence).  The tricky thing is it doesn't always happen, so my guess is it's caused by just the right balance of variables - perhaps FL selection, relative winds, cost index, CLB vs. OPEN CLB, or maybe something else?  I'll see if I can gather any shots of it happening.  It's one of those things that bothers me more just to know what's causing it than any affect it has on usability.

 

For what it's worth, FPS isn't an issue.  I'm typically getting a smooth 40-50 FPS once I escape any cloud cover.  I bottom out at between 20-30 FPS with minor occasional stutter on the ground or low altitude near FSDT KJFK and Orbx SoCal KLAX.  Those are by a long shot the most FPS/VAS unfriendly add-ons I use.

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  • 3 weeks later...
On ‎18‎/‎05‎/‎2017 at 6:57 PM, Lotus3xiG3 said:

Mmmmh, thats weird... I personally do not have this issue! When approaching my cruising altitude the engines gently spool down and the aircraft lowers the nose! 

Without criticizing you, are you sure that you have Autothrust active? Would be great, to get some pictures of the ECAMs, the FCU and the PFD, when this occurs!

 

All set correctly, been flying the busses for......well.....a long time :)  Next time it happens I will grab a screen shot.

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I am pretty sure it's a bug. Always happened to me and I'm quite sure I'm doing everything correctly. I usually "fix" it by changing to selected climb 1000 feet before cruising altitude. 

 

Btw, I think it only happens when you are climbing to the altitude you selected in the INIT page as cruise alt. so you might wanna put a higher FL in the INIT page. 

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  • 2 weeks later...

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