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Strange Managed Speed problem


Bernd E.

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I add myself to the list of people affected with this issue!

 

I did some test flights, everything went well. Updated to the latest, now having this twice in my last 5 flights.

 

I did notice that the speed the Airbus managed mode was trying to go was the same speed that was entered in the PROG decent page even if I was still far from the TOD!

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I just want to add those 2 screenshots of the PFD and the PERF page. From what I understand the plane indicates that it is in ALT CRZ and does not want to go to the speed it should go according to the PERF page. When I set it in selected mode, the speed is fine so the autothrottle works fine, but not in managed mode.

 

For this flight I was in cruise for about one hour before it decided to drop speed. For the whole time it had hold the managed speed fine! But suddenly engines went IDLE and dropped speed fast to go to 128 knots even if PERF page shows 0.78 managed speed

 

EDIT: When I started the descent, managed speed went to 230 which is the speed shown in the PERF DES page. So only the CRZ one is broken

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I"m also experiencing the same issue. I'm noticing climb rates are much slower than normal for the loaded weight. 

 

Once at cruise for some time, the AP will drop the airspeed dramatically and the plane goes into a stall and begins to descend. I'm able to continue if I disable managed speed. 

 

I had also just posted a thread over at FSDT to mention that GSX2 is loading the a320 in a strange way. The loadsheet calls for 180 pax and 6.5mt of cargo. When the GSX vehicles arrive, less than 10 pax board and almost no cargo and bags are loaded. Perhaps this is related?

 

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  • Deputy Sheriffs
53 minutes ago, Chris1983 said:

And selecting speed is not very real :(

 

Why not? We do it all the time. And I would say that as long as we have this bug it is even realistic to do so if you as a pilot knows this can happen. 

 

Ofcourse the bug should be fixed asap and this is not acceptable in the long run. 

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So after being told that everything works prior to the last couple of updates I was told I was suddenly not imputing data into the MCDU correctly. Now a clean install of 4.4 will fix this? Problem started with 4.3. Seems like we are simply having ideas thrown at us instead of solutions. 

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  • Aerosoft

I am sorry you feel that way.  Yet as I said and user djspatrick confirmed this is something we have seen a few times.  I assume you have seen his post only a few posts above you?

 

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I seem to be one of the users having this issue, as well as a CTD problem when spawning the CRJ (reported in another thread - Hans has been researching).

 

I think these 2 problems are related, however that may have found itself into my sim. So a reinstall will help I see, I believe it.

Ok, so my Saturday is now planned. 

 

Will report back. 

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I've just did a full re-install due to upgrading to P3D v4.4. I thought I was ok, just did 3 flights where everything was ok, but no, it just happened on the 4th flight as I am cruising at FL350 between CYYZ and KMIA. Managed speed dropped to 120 knots, engines went idle. I am around 45 minutes from TOD, so I had to put speed into Selected mode to continue.

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8 hours ago, Draftstone said:

I've just did a full re-install due to upgrading to P3D v4.4. I thought I was ok, just did 3 flights where everything was ok, but no, it just happened on the 4th flight as I am cruising at FL350 between CYYZ and KMIA. Managed speed dropped to 120 knots, engines went idle. I am around 45 minutes from TOD, so I had to put speed into Selected mode to continue.

v4.4, just happened to me YVR-LAX. Plane stalled out and started dropping... engines appeared to be producing thrust but really weren't doing anything, put it in togalock and it fixed it. Had to take the plane out of managed.

 

Happened when I was coming up on my first altitude/speed restriciton fix.

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It's certainly a bug.
Today - I changed my destination runway around from 36R to 36C  ... just trying to get some fresh data into the flight plan .. and the normal managed speeds came back.

I'll try again when I can re-produce the issue - but if anyone's in mid-flight right now and can try it I'd be curious if it's a good temporary work-around.

 

I'm also curious if those having the problem have been closing the disconnect between the STAR and the final approach fix.

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On 12/9/2018 at 10:09 AM, bob34 said:

It's certainly a bug.
Today - I changed my destination runway around from 36R to 36C  ... just trying to get some fresh data into the flight plan .. and the normal managed speeds came back.

I'll try again when I can re-produce the issue - but if anyone's in mid-flight right now and can try it I'd be curious if it's a good temporary work-around.

 

I'm also curious if those having the problem have been closing the disconnect between the STAR and the final approach fix.

Mine had an open disconnect, it was the IRNMN2 in to LAX which has a downwind then unattached inbound final approach course. And I had this issue.

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On ‎12‎/‎9‎/‎2018 at 11:09 AM, bob34 said:

It's certainly a bug.
Today - I changed my destination runway around from 36R to 36C  ... just trying to get some fresh data into the flight plan .. and the normal managed speeds came back.

I'll try again when I can re-produce the issue - but if anyone's in mid-flight right now and can try it I'd be curious if it's a good temporary work-around.

 

I'm also curious if those having the problem have been closing the disconnect between the STAR and the final approach fix.

 

Yes, I always CLR ALL disconnects. 

 

Changing destination runway has worked to restore managed speed after "drops" for me; however, managed speed may drop again.  I've gotten to the point now that for CRZ I will fly in manual mode, until just before TOD; then if the FMC DES PERF page shows a ridiculous speed like 204 kts, I change runway to restore correct managed speed; and set managed speed mode just short of TOD to get the decent managed speed mode.  If you leave the managed descent mode speed at 204 or whatever it drops to, your TOD will be way late and in manual descent you have to keep playing with VS to make waypoint altitude constraints.  May as well be flying the CRJ.

 

Also be aware this issue is reported in the Flight Model/AP/FMS forum.

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On 12/14/2018 at 9:21 AM, Mathijs Kok said:

Thanks for that report. We do have some other users who report they still see the issue so we are still interested in feedback.

 

 

v1.2.2.0 confirmed managed speed issue still exists. Take a look at the MCDU... the only waypoint here with an actual speed restriction in it is ROBUC with the 260 knot restriction. Everything around it the airplane is trying to fly at 210. No disconnects in the flight plan, I (quite incorrectly for procedure) deleted the MANUAL segment as well as the discontinuity and it still has messed up speeds.

 

This is the ROBUC3 arrival into KBOS in the A321 IAE

 

EDIT: sorry not a great capture, ROBUC is the fix right after BANKI

 

Another edit: DISREGARD: it fixed itself... the speeds are now correct for the descent now that I have reached the ToD. Still a little bit of an odd and optimistic descent, but the plane has not dropped out of the sky this time so that's a win. I'll keep an eye on it though

 

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Hey
sorry for my bad English
Just made a flight with the 320 version 1.22.
and got the following problems!

1. during taxiing suddenly react very slowly to actions, actually temporarily uncontrollable. as suddenly as it came, it also went away

2. after the start actually the same as times the taxi moment device reacted slowly to actions. also on the CDU. This lasted 30 seconds and also recovered itself. during this inertia the plane went down sharply for 30 seconds. but this also recovered automatically

3. when the cruising level is reached, the speed will go its own way. and do not worry about the speed of the CDU. Only when you deactivate the autothrottle and activate it again will the plane pick up the speed of the CDU again.

 

I can remember something, that the same problems also played in the airbus extendend, but I think you can still look back in the logs because I do not know for sure anymore. I hope I am clear enough, and that I helped you with this problem description

Greetz

Chiel

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3 hours ago, mopperle said:

Hi Chiel,

your problem looks very different from the other ones. How many fps do you have when this all happens?

Hello

 

The firs tone is different but the other 2 are simailar with de speed problem en de bumping problem.

i dont now how muich fps i hat. ad that time.

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