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Mickey4673

Managed Speed lost during flight

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Could it be that everyone that has climb performance problems lately flies with “real” weather and takes off with ice buildup on the wings? Ergo do you have wing and engine anti ice on after take off in icing conditions? We had these “same” problems with the last 32bit release some years ago when wintertime started. I am not saying that is the solution but just asking to troubleshoot the problem. 

 

I do not mean the managed speed goes to Vls in climb/cruise bug here but rather the off topic loss of climb performance chatter in this thread. 

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I flew several successful flights and yesterday, the A318 went to A.Floor. Clear skies @ fl400. The latest experimental 1.2.2.1.   Win10 64 , clean new P3Dv4.4 install when it was released. No new software or hardware change to my computer. Latest Nvidia drivers.

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42 minutes ago, marvic said:

I flew several successful flights and yesterday, the A318 went to A.Floor. Clear skies @ fl400. The latest experimental 1.2.2.1.   Win10 64 , clean new P3Dv4.4 install when it was released. No new software or hardware change to my computer. Latest Nvidia drivers.

 

In this case you were flying 1000ft above the service ceiling (without looking it up, I'm pretty sure the service ceiling for the A318 is 39,000ft), and though unlikely it's also possible there was moisture up there so anti-ice might have played a roll.  Probably not, but it's something to consider in the mix.

 

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Yes Dave, I understand and I flew fl410 for three flights, and fl350 for three flights before the before the incident with the clear skies and no ice forecast or PIREPs indicating any icing.

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1 hour ago, marvic said:

Yes Dave, I understand and I flew fl410 for three flights, and fl350 for three flights before the before the incident with the clear skies and no ice forecast or PIREPs indicating any icing.

 

Thank you my friend!

 

I'm working on a post with instructions that will help those having this issue to assist us in nailing this down, but unless something changes to my schedule today I won't be able to post it until tomorrow as i have to research a few things before posting it.

 

We thank all of you guys for helping us track this darned issue down.  Hopefully it will be resolved before we release Connected Flight Deck, but if not then CFD might also help us track this things down since none of our Beta Testers are able to duplicate this issue (which is of course very frustrating for you guys as well as us!).

 

 

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Thanks Dave, I will be more than glad to assist in finding this issue. I will wait for your instructions, happy new year.

 

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just to add the same thing happening on my flights since the last 2 updates. i wondered what had happened when the aircraft decided it was gonna go slow so have to fly selected speed to keep the speeds right. it didnt happen until late on the last flight but the same flight flown again its happened after thrust reduction. no constraints in just didnt see the correct mannaged speed in the mcdu.

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Has anyone considered if the performance (load on P3D V4) is a factor here ?
(CPU, DISK, RAM, GPU etc) - could explain why many are fine and others have the issues more frequently.
(wondering if the code gets behind in any of the many loops that must be running constantly measuring, updating etc)

Two things to try:

1 - for anyone experiencing the problem lower your settings (graphics, world, lighting, scenery etc) and see if you experience the same.
2 - for anyone not experiencing the problem adjust all the settings way up to put a much larger load on P3D and your computer.

See if any change.

Report results...

 

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15 minutes ago, julian46 said:

Has anyone considered if the performance (load on P3D V4) is a factor here ?

I would say definitely not. This would result e.g. in low fps. But on my meanwhile low-end system, I never experienced such a problem.

And looking at the history in this topic, fps never was an issue and for some users a recent update solved the problem.

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I also doubt that performance is an issue. As long as FPS is steady and over 17 fps the systems are updated enough.

 

As you know we hired a new person on the team who will be responsible for testing, Jouka. The first thing he will be doing is trying to make sense of the issues that are hard to track down and are not always repeatable. We'll do that by setting up special topics to make sure information does not get lost.

 

 

 

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Hi all i had it happen again sadly, first time in a few flights ....... i was altering the CRZ FL at the time and it just went down to about 195 knots, i mangaed to get it back to managed mode by selecting manual speed then using the MCDU to go direct to the next fix.... i was then able to select managed speed and completed the flight with-out issue , the return also went fine as i did not alter the CRZ this time.

Also its not performance related as i was at 30 fps locked at 30 .

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On 1.1.2019 at 16:46, julian46 sagte:

Has anyone considered if the performance (load on P3D V4) is a factor here ?
(CPU, DISK, RAM, GPU etc) - could explain why many are fine and others have the issues more frequently.
(wondering if the code gets behind in any of the many loops that must be running constantly measuring, updating etc)

Two things to try:

1 - for anyone experiencing the problem lower your settings (graphics, world, lighting, scenery etc) and see if you experience the same.
2 - for anyone not experiencing the problem adjust all the settings way up to put a much larger load on P3D and your computer.

See if any change.

Report results...

 

 

At least i have, yes. I saw that posts about the needed fps for flightmodel to update in other topics so this is also what i usually tell others when they experience problems.

 

This problem is not related to a certain moment only. If it appears there is no way to revert from this state anymore. It happens with 40, 50 and 60 fps. Not something like the random weird behaviour when fps may be low. THis is different and its a broken state somewhere, of something.

 

For example: i have mentioned i tried to manually get rid of the small speed value. For me it was always 192 kts where it reverted to when going into managed mode, despite i saw something like 0.76 there. Then i scrolled forward in the flightplan and i found this value, the 192 written next to the the T/D marker on the FMC flightplan. Where usually the speed is written like 0.77/320. Here this 192 was somehow hardcoded and no matter what i manually set on all waypoints below or after the T/D reverted to this value.

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Just happened to me again today, flight plan:

 

TXKF N0461F360 DASER L459 SAVIK YAALE YETTI MOUGH DONAA OWENZ CAMRN KJFK

 

Just as I passed MOUGH, I first heard the engines cut back and noticed that managed speed (as displayed on the PFD) dropped from M0.80 to 110.  PERF CRZ and F-PLN continued to show the correct values regardless.

 

Following suggestions on the other thread, a DIR TO to the next waypoint (DONAA) did not fix the problem.  Before DONAA, I was instructed to begin descent but that didn't fix the problem either (rather giving a managed speed of 215; still way too low).  It wasn't until I approached 10,000 feet altitude that the managed speed behaved more normally (with the 238-255 bracket on the PFD), although somewhat oddly it stayed to the lower end of the range instead of the target 250.

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I have opened and pinned a new thread for this issue with more detailed information on how to report so that we can track everything easier. Therefore I am locking this topic. Thanks everyone for the reports. We will go through them and review with the reports on the new thread to track the issue and hopefully solve it soon.

Link to new thread with instructions on how to give best possible bug report.

 

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