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Aircraft overshoots selected altitude in first climb constraint


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Hi, loving the MSFS CRJ, however;

 

The aircraft will overshoot the first selected altitude in both speed climb mode and VS mode.

 

For example, first constraint in SID is 5000'. I set 5000' as target altitude, FMS flight plan also has 5000' as first constraint. Take off in speed mode v2 +20 and aircraft overshoots 5000' and keeps climbing well above 6000' before I get a telling off from ATC! (Pilot2ATC). I then have to use VS descent to re acquire 5000', or disengage AP and go manual.  Same overshoot happens in VS mode with VS at a modest 2000 FPM.

 

I may say I have no problems in descent. The VNav is perfect!

 

Thanks.

 

 

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Need more info. Mine nails it unless I do something wrong. EG: Forgetting to press the toga button when lined up on the runway as stated in the videos and tutorials to enable the flight director.

 

I forgot to press it last night and AP wouldn't work properly until I did it and reset the AP modes.

 

I bet that simple button press that we don't have to do on any other aircraft is responsible for a lot of peoples issues. But it is documented.

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vor 9 Stunden , Mathijs Kok sagte:

Are you sure you are not having too much speed? As the systems do not take your speed into account you have to do that. 

 

This issue refers to many others:

 

Autopilot Irregularities - Manual Flight, Autoflight and Flight Management - AEROSOFT COMMUNITY SERVICES

 

Zitieren

 

When reaching an altitude for the first time of the flight, engaging AP while PFD shows ALT CAP it tends to overshoot the altitude for some hundred feet.

Selecting AP before it shows ALT CAP captures it as it should.

Same strange behavior when dead on altitude and activating AP as seen in my video.

Regards, Herbert

 

 

Aircraft is jumping after engaging AP - Manual Flight, Autoflight and Flight Management - AEROSOFT COMMUNITY SERVICES

 

A/C goes nose up when activating autopilot - Manual Flight, Autoflight and Flight Management - AEROSOFT COMMUNITY SERVICES

 

When flying manually with armed SPEED Mode 250kts till first altitude constraint when PFD blinks ALTS CAP and I activate the AP for the first time, the plane starts to tilt up and overshoots the first constraint for hundreds of feet.

Same when manually flown to the first constraint, stabilized and activating Autopilot, see video.

If I engage AP as example two thousend feet before reaching the first constraint, it behaves as it should, continuing the stable climb and slowly catching the altitude.

Also, when reaching next constraint using the AP.

 

Altitude Capture Issue - YouTube

  

I think, it really would be necessary to have a "issues known and worked on" list as example MSFS has, because I was sure this problem, after many threads, was on the bugs list. People wouldn´t start threads again and again regarding same issue.

 

I use Modern, CG lever on the right, sending the standard fuel and payload parameters to sim, Flaps 8, Trim 7.2 at takeoff, TOGA pushed once, climb is stable using 210 to 250kts before pushing first time AP.

It might have been overseen, because real pilots would rather engage AP at 600ft and that way it works, but this plane flys nicely manually so I appreciate that way.

 

Regards,

Herbert

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vor 7 Stunden , Thx1137 sagte:

Need more info. Mine nails it unless I do something wrong. EG: Forgetting to press the toga button when lined up on the runway as stated in the videos and tutorials to enable the flight director.

 

I forgot to press it last night and AP wouldn't work properly until I did it and reset the AP modes.

 

I bet that simple button press that we don't have to do on any other aircraft is responsible for a lot of peoples issues. But it is documented.

Where is this TOGA button?
Thanks
Peter LSZH

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Here´s another video

 

This time, I was above the selected speed and above the FD so maybe that´s a problem for the AP.

Engaging AP at 6800ft for catching 7000ft it starts to pitch up instead of following the FD.

This behaviour often starts well 1000ft below the assigned altitude.

 

(9) Altitude Capture Issue - YouTube

 

Regrads,

Herbert  

 

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vor 2 Minuten, petermaxkoller sagte:

Where is this TOGA button?
Thanks
Peter LSZH

Click at the upper screw or at the throttle button.

TOGA upper screw.jpg

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1 hour ago, petermaxkoller said:

Where is this TOGA button?
Thanks
Peter LSZH

The screw Puukka pointed out. It is also the red button on the throttle. Most jets Ive flown including the PMDG have it in the same places so it is pretty standard.

It is illustrated explained and pretty well in the tutorial.

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1 hour ago, Puukka said:

Here´s another video

 

This time, I was above the selected speed and above the FD so maybe that´s a problem for the AP.

Engaging AP at 6800ft for catching 7000ft it starts to pitch up instead of following the FD.

This behaviour often starts well 1000ft below the assigned altitude.

 

(9) Altitude Capture Issue - YouTube

 

Regrads,

Herbert  

 

Obviously speed mode was not engaged so that is one mistake that can obviously explain that behaviour. The video doesn't show anything else so that's all I think anyone can deduce.

 

Basically you said "go to this altitude but I'm not going to give you a vertical AP mode to tell you how to get there" so it doesn't surprise me that it won't work properly because it is waiting for you to finish telling setting it up. The aircraft isn't going to hold your hand, the system expect you will follow the rules and know how to use it. It doesn't have a beginner mode because it expects only trained people will use it.

 

For us the training is the tutorial and the tutorial works. As long as you do all of it.

 

TOGA button:

 

Speed Mode and initial AP usage:

 

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As soon ALTS CAP is engaging, SPEED MODE disengages, as you should know. The video starts in ALTS CAP Mode

 

How do you explain that video?

Altitude Capture Issue - YouTube

 

The difference is: At the totorial video he selects Autopilot at 600ft. Software shouldn´t work only in one way.

 

I have GPL, PPL, 50 hours B737 sim training Multicrew, I flew the CRJ hundreds of hours at the P3D without this issue.

Will do more videos and tests, maybe I can help you with that.

 

Regards,

Herbert

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Here we are, just my next try:

 

I´m manually flying 250kts in armed SPEED MODE, selected 5000ft

It starts the ALTS CAP phase, I engage the AP and instead of keeping the climb stable it starts to climb steeper and overshoots the constraint altitude.

 

 

 

I did several other trials using 210kts and it worked as it should!

So it might be an issue related together with airspeed.

 

At my second video it starts the climb when stabilized at altitude, I guess, speed shouldn´t matter, when not climbing. 

 

 

Regards,

Herbert

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Studying my videos I´ve stabilized Trim at 4.6 for the climb and 3.6 for keeping altitude.

 

Engaging AP produces a sudden jump to 5.4 and then moves nose up to 3.6

 

Seems, trim (AP) gets out of control when selecting AP during climb to, and being at the first constraint.

Regards,

Herbert

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36 minutes ago, Puukka said:

How do you explain that video?

I don't. I get the apparent bug on rare occasions myself (last flight actually) but it is also no the topic of this post so mixing it in here is not useful. It could be considered similar but it certainly isn't the same, this topic is about hitting a constraint. That is different to "Not maintaining a preset altitude on enabling AP". I've never had an issue hitting a constraint. But this is what I always saying. If there are no details then most of the time was can't be even sure we are talking about *exactly* the same thing. In programming details are everything.

 

So thanks for at least trying to show a bit of video. But to get on top of it we need more. It can have boring bits edited out but ideally it would have:

* The flight plan (I suspect not having a sid or star causes some issues but haven't spend time proving it yet)

* The MSFS weight and balance screenshot.

* The FMS setup. Even better if the FMS setup is saved and attached as a file we can load. That would be perfect.

* Video of entering the runway to passing the first waypoint at least.

* If the issue happens after that, then video of a little before the issue starts.

 

All of that gives *everyone* a reproducible way to hopefully trigger the issue. There can be no question we would all be on the same page.

 

It doesn't matter what qualifications we have unless it is as a CRJ pilot. I have literally thousands of hours since the 1980s in flight simulation. I owned every PMDG and high end X-Plane aircraft and flew the 737 (my favorite) and ToLiss aircraft a lot. That means absolutely nothing to a CRJ. I actually have a light aircraft license too and owned my own for a couple of years. That also means nothing too.

 

We all know there are bugs, the devs have stated that some are already fixed in their build. But not hitting a climb constraint is not one I've experienced myself. So I have to think I'm doing something different, and obviously better, to others that do have an issue with it.

 

I can get the AP to work horribly. By doing those things I've been talking about in a number of posts and many posts sounds like issues caused by what I'm talking about.

 

It may please you to know though that I just had a flight where I didn't make a mistake (I'm pretty sure) where all hell broke loose. That is the second or third time in around 35 flights. I think all three didn't have a SID and in this case I didn't select a STAR. I'll try to confirm tomorrow.

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vor 2 Minuten, Thx1137 sagte:

It doesn't matter what qualifications we have unless it is as a CRJ pilot. I have literally thousands of hours since the 1980s in flight simulation. I owned every PMDG and high end X-Plane aircraft and flew the 737 (my favorite) and ToLiss aircraft a lot. That means absolutely nothing to a CRJ. I actually have a light aircraft license too and owned my own for a couple of years. That also means nothing too.

You are right, sorry for that, thanks for the insights. Will bring these infos.

Regards,

Herbert

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Here we are

 

I´ve done my videos without flightplan yet, because the issue is the same with and without FLP.

SimBrief: My aircraft, ESGG-ESMS and I´ve only edited the Cruise Altitude from FL250 to 210, I like to use lower levels as suggested, just to enjoy cruise and landscape for longer.

 

Default performance sent to FMS and Sim, Altitude to set 5000ft

I´ve skipped the speed set to 210kts and selected 250kts, regulary I try to follow that: 

 

GEAR UP: SPEED Mode,  400ft HDG or NAV, 1000ft CLB Thrust, 3000ft 210kts, FLAPS UP: SPEED 250kt

 

Here´s the entire video showing takeoff and climb to the preselected altitude. When selecting AP Trim jumps again.

 

 

 

ESGGESMS.flp

 

Flight Plan Sheet.jpg

Flight Plan.jpg

FMS-1.jpg

FMS-2.jpg

FMS-3.jpg

Perf.jpg

Perf-1.jpg

Perf-2.jpg

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Yes, the autopilot doesn't like levelling off at low altitudes much - too much energy with full CLB power. I recommend to slowly decrease the throttle setting when the capture phase starts. This helps to get around the problem.

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1 hour ago, Puukka said:

Here we are

 

I´ve done my videos without flightplan yet, because the issue is the same with and without FLP.

SimBrief: My aircraft, ESGG-ESMS and I´ve only edited the Cruise Altitude from FL250 to 210, I like to use lower levels as suggested, just to enjoy cruise and landscape for longer.

 

Default performance sent to FMS and Sim, Altitude to set 5000ft

I´ve skipped the speed set to 210kts and selected 250kts, regulary I try to follow that: 

 

GEAR UP: SPEED Mode,  400ft HDG or NAV, 1000ft CLB Thrust, 3000ft 210kts, FLAPS UP: SPEED 250kt

 

Here´s the entire video showing takeoff and climb to the preselected altitude. When selecting AP Trim jumps again.

 

 

 

ESGGESMS.flp 612 B · 0 downloads

 

Flight Plan Sheet.jpg

Flight Plan.jpg

FMS-1.jpg

FMS-2.jpg

FMS-3.jpg

Perf.jpg

Perf-1.jpg

Perf-2.jpg

 

 

Hello. I see similar results.

 

I will try and record a video.

 

My route is as per SimBrief. EGKK to EGPN. (PDF attached)

 

Before take off, I have the first constraint of FL056 entered into AP altitude select. 

 

I select Speed mode and enter climb reference speed at V2 + 20 (approx 165).

 

I select Nav mode.

 

I select TOGA, take off and at 1700' engage AP.

 

Aircraft climbs at selected speed mode but overshoots the selected altitude of FL056.

 

I will fly this again and record a video.

 

Thanks. 

 

Regards

David

 

I climb to 1700' after takeoff.

 

 

EGKKEGPN_PDF_1616856918.pdf

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Thanks for your info, Hans

I´ll be able to live with this workaround, as I like to fly manually a lot,  I´m especially pleased about the realistic moving Lateral Flight Director of this model, very well done!

Regards,

Herbert

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5 minutes ago, Hans Hartmann said:

Yes, the autopilot doesn't like levelling off at low altitudes much - too much energy with full CLB power. I recommend to slowly decrease the throttle setting when the capture phase starts. This helps to get around the problem.

Thanks Hans.

I suspect this is an Asobo issue, since I dont recall it in the P3d CRJ?

I will re fly with airspeed a bit lower.

Regards.

David

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couple of things.

 

1. You hit the AP engage button right after the ALT alert went off.  At the climb rate you were at that is a lot of stuff to shove to the airplane in a short period of time.  I think that the real CRJ crew would have just leveled in manual flight mode at that time.

2. You are in climb power pretty much until ALT capture.  You are the autothrottle in the CRJ.  Start pulling power when you hear the alt alert horn.  The aircraft will already have begun a level off shortly after that.  Remember that in a climb with A/P engaged, you will be asking the plane to 1. climb to an altitude 2. do so at either a specified V/S or IAS.  So the aircraft will fight until the last minute to do what you told it to do.

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2 minutes ago, Puukka said:

Thanks for your info, Hans

I can live with this workaround well, as I like to fly manually a lot,  I´m especially pleased about the realistic moving Flight Director of this model, very well done!

Regards,

Herbert

Hans's advice is NOT a workaround. The CRJ is not a set it and forget it aircraft.  You have to be constantly aware of the throttles especially during alt capture.  You can get to slow or too fast quickly. 

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1 minute ago, herky20 said:

Thanks Hans.

I suspect this is an Asobo issue, since I dont recall it in the P3d CRJ?

I will re fly with airspeed a bit lower.

Regards.

David

Yes, currently a custom autopilot is something that is simply not possible to do. With the current very limited debugger functionality and compile times at about 7-8  minutes for every little change, I'd probably be dead by the time I got it done.

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1 minute ago, Hans Hartmann said:

Yes, currently a custom autopilot is something that is simply not possible to do. With the current very limited debugger functionality and compile times at about 7-8  minutes for every little change, I'd probably be dead by the time I got it done.

 

Copy that!

On the other hand your FMS route execution is absolutely superb! It looks like you recoded the Asobo model since the CRJ flies the route impeccably without any silly USR waypoint additions that send you back 180 degrees.

 

You currently have the very best pax aircraft in MSFS......beating the FBW because they still use Asobo waypoints!

 

Thanks.

Regards

David

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13 minutes ago, herky20 said:

 

Copy that!

On the other hand your FMS route execution is absolutely superb! It looks like you recoded the Asobo model since the CRJ flies the route impeccably without any silly USR waypoint additions that send you back 180 degrees.

 

You currently have the very best pax aircraft in MSFS......beating the FBW because they still use Asobo waypoints!

 

Thanks.

Regards

David

I only use MSFS's HDG Hold function for the LNAV part. The whole waypoint logic and calculations are my own.

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