ScottecLEMD 14 Posted May 15, 2017 Share Posted May 15, 2017 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 Link to comment Share on other sites More sharing options...
Sabretooth78 56 Posted May 15, 2017 Share Posted May 15, 2017 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. Link to comment Share on other sites More sharing options...
Lotus3xiG3 118 Posted May 15, 2017 Share Posted May 15, 2017 Do you guys have stable FPS above or around 18? This is needed for the FBW to work correctly... Link to comment Share on other sites More sharing options...
ScottecLEMD 14 Posted May 15, 2017 Author Share Posted May 15, 2017 Perfectly stable FPS for me, and at FL's 330-390 there's not much to interfere with smooth FPS. Link to comment Share on other sites More sharing options...
HAL-9000 10 Posted May 16, 2017 Share Posted May 16, 2017 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. Link to comment Share on other sites More sharing options...
ScottecLEMD 14 Posted May 16, 2017 Author Share Posted May 16, 2017 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. Link to comment Share on other sites More sharing options...
Lotus3xiG3 118 Posted May 18, 2017 Share Posted May 18, 2017 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! Link to comment Share on other sites More sharing options...
FraPre 89 Posted May 18, 2017 Share Posted May 18, 2017 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. Link to comment Share on other sites More sharing options...
Sabretooth78 56 Posted May 19, 2017 Share Posted May 19, 2017 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. Link to comment Share on other sites More sharing options...
ScottecLEMD 14 Posted June 8, 2017 Author Share Posted June 8, 2017 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. Link to comment Share on other sites More sharing options...
Lotus3xiG3 118 Posted June 8, 2017 Share Posted June 8, 2017 Alright! Link to comment Share on other sites More sharing options...
datguytho 38 Posted June 8, 2017 Share Posted June 8, 2017 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. Link to comment Share on other sites More sharing options...
ScottecLEMD 14 Posted June 16, 2017 Author Share Posted June 16, 2017 Finally a picture to show the final few hundred feet to TOC and the increase in ROC. Please login to display this image. Link to comment Share on other sites More sharing options...
datguytho 38 Posted June 23, 2017 Share Posted June 23, 2017 Just want to add that this does not happen in OP CLB (which is actually the same as managed but without constraints). thats how I "fix" it. Link to comment Share on other sites More sharing options...
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