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A/C goes nose up when activating autopilot


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After takeoff, i go into a climb and when I enable the autopilot, it should usually set the current vertical speed as climb rate. When I activate the A/P, the aircraft takes his nose up extremely (about 5000ft/min climb rate) until i manually switch to V/S mode and adjust the climb rate. How can i prevent this, it is really annoying.

 

 

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So you turn AP on without anything else selected and it climbs at 5000fpm? You don't say anything about all the AP settings so I've no idea what you are seeing.

If you just pressed AP and noting else I would have thought it would be wings level but an obvious solution is fly level, press the Alt button to set the AP altitude to your current altitude then enable the AP. It is what I do and it seems OK.

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On 20.3.2021 at 19:04, Puukka sagte:

I´ve just recorded a short vido showing this issue.

I´m stabile and settled at 5000ft, 250kts, FD is centered. ALT is armed at 5000ft.

I engage the AP and the plane starts a harsh climb well above the altitude.

Regards,

Herbert

 

Altitude Capture Issue - YouTube

Sounds quite similar to my problem.

When in Speed Mode climbing and activating the AP late, it starts to climb radically, or when having been flown manually to the first constant altitude and activating the AP when stabilised, as seen in the video.

After having reached next altitude with AP (climb mode or VS descend) it works as it should.

Regards,

Herbert

 

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Well usually if you activate the A/P it should activate wings level and pitch. So it should climb with the current rate of climb and hold the wings level. But it takes the nose up and does not hold the current pitch. When I activate the V/S mode and set it to a certain value, this V/S mode is immediately activated when switching the A/P on and then the autopilot will hold this rate of climb. But is this the way it is supposed to work?

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  • 2 weeks later...

I had this issue too last night. Set altitude to FL300. The plane climbed without problem in speed mode, 250kt up to 10.000ft. Then I set 290kt. Suddenly there's a problem with my engine levers (they go all the way to idle for like 1 sec. for some unknown reason and then go back to the CLB detent). After this the AP just wouldn't put the nose down and maintain the selected speed, instead it just wanted to pitch up. The plane quickly lost speed and fell down, so I disconnected AP and stabilised it again at FL150. Then I turned AP on again and the same happened. I tried setting the target altitude to my current one, so that it wouldn't want to climb and that didn't seem to work. Very frustrating.

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On 3/25/2021 at 7:18 PM, narfomat said:

Well usually if you activate the A/P it should activate wings level and pitch. So it should climb with the current rate of climb and hold the wings level. But it takes the nose up and does not hold the current pitch. When I activate the V/S mode and set it to a certain value, this V/S mode is immediately activated when switching the A/P on and then the autopilot will hold this rate of climb. But is this the way it is supposed to work?

My personal opinion:

PMDG - System simulation that lets you do anything anyway you want. Even if it would never ever be used in real life.

Aerosoft - System simulation that lets you fly like a real pilot. They do not spend effort and money (notice the Aerosoft/PMDG price difference?) simulating aspects that are not realistic from a real-world pilots procedures perspective.

 

Going by a manual I have it should probably hold the pitch. But seeing most airline CRJ SOPs don't even allows VS to be used on climb (going by some CRJ drivers) then I'd doubt pitch hold would be allowed either. But maybe one will chime in if I've made a mistake.


 

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vor 2 Stunden , jaimilonchus sagte:

I had this issue too last night. Set altitude to FL300. The plane climbed without problem in speed mode, 250kt up to 10.000ft. Then I set 290kt. Suddenly there's a problem with my engine levers (they go all the way to idle for like 1 sec. for some unknown reason and then go back to the CLB detent). After this the AP just wouldn't put the nose down and maintain the selected speed, instead it just wanted to pitch up. The plane quickly lost speed and fell down, so I disconnected AP and stabilised it again at FL150. Then I turned AP on again and the same happened. I tried setting the target altitude to my current one, so that it wouldn't want to climb and that didn't seem to work. Very frustrating.

This is usualy when something like a Button Binding / Axis interfeeres with the CRJ.

The AP won't move the THR in the ACFT (it's not a Boeing) so if they moved, then something in your controlls told it to do.

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vor 4 Stunden , Thx1137 sagte:

Aerosoft - System simulation that lets you fly like a real pilot. They do not spend effort and money (notice the Aerosoft/PMDG price difference?) simulating aspects that are not realistic from a real-world pilots procedures perspective.

 

Going by a manual I have it should probably hold the pitch. But seeing most airline CRJ SOPs don't even allows VS to be used on climb (going by some CRJ drivers) then I'd doubt pitch hold would be allowed either. But maybe one will chime in if I've made a mistake.

 

This gets missinterpreted a lot. Aerosoft does not simulate failures. They do though simulate systems e.g.: If your ENG needs BLEED AIR to start, it won't start without it (even though the SOP and Checklist says you have to provide BLEED AIR).

If you as a pilot deliberately turn of FUEL to an ENG in mid flight and something weird happens, this is not a failure but a pilot mistake and Aerosoft will probably ignore it.

 

So, if the AP should hold ROLL and PITCH when engaged without any other mode, then it should behave like that. I just tested it pushing the AP just after TO and it did hold ROLL and PITCH (BUT I also provided the CRJ with enough THR to be able to mantain that PITCH). So if you have a 15° PITCH but not enough PWR to maintain lift, the CRJ will plummet to the ground.

 

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3 hours ago, GEK_the_Reaper said:

This is usualy when something like a Button Binding / Axis interfeeres with the CRJ.

The AP won't move the THR in the ACFT (it's not a Boeing) so if they moved, then something in your controlls told it to do.

I know something must have interfered with the controls, and I know the CRJ is not to blame for that, but the problem came later when the plane wouldn't stop pitching up no matter what I told the AP to do.

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@jaimilonchus can I ask you to open another thread if you experience the issue again?

 

This thread is quite old and it seems that the OP does no longer have the issue. I would say that what you have experienced is something different then that what the OP has had therefore I would lock it.

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It’s been happening to me on both xplane and the crj. On xplane, I found out it was because my ch yoke doesn’t go fully back to its neutral position when released. Let’s say that the hands off position is between 0% forward and 5% back pressure. I was trimming it to 5% back pressure. Once the ap was engaged, it was being overriden by this 5% and pitching up. Therefore, try to make sure that you are trimming the aircraft and engaging the autopilot when your yoke is dead on centered. 

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vor 12 Stunden , GEK_the_Reaper sagte:

@jaimilonchus can I ask you to open another thread if you experience the issue again?

 

This thread is quite old and it seems that the OP does no longer have the issue. I would say that what you have experienced is something different then that what the OP has had therefore I would lock it.

 

Hi GEK_the_Reaper, should I open another thread?

My issue is still unsolved.

Either when manually flying to and stabilized at the first constraint:

 

https://youtu.be/ZYF88nFiRkA

 

Or when I activate AP just before or during the ALTS CAP Phase in armed SPEED Mode it´s apruptly changing the trim and climbing rapidly, overshooting the armed altitude,

(AP Activation at 2:05)

 

https://youtu.be/xPS-4YXAdWk

 

It´s only keeping the AOA when activating the AP thousands of feet before the constraint, as the Dude does at his tutorials.

Since I´d like to fly the SID manually to the first constraint, it´s not possible at the moment. It would start to climb even when stabilized at the altitude with a certain speed as example 250kts.

 

Thanks and regards,

Herbert

 

 

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Hello @Puukka I just tested this behaviour on my end and can confirm the same PITCH UP when engaging AP and close to selected ALT.

Thank you for the report and the videos. I raised the Q into the test group and also made an entry into our tracking list.

 

Will keep you posted.

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  • 1 month later...
On 10.4.2021 at 10:28, GEK_the_Reaper sagte:

Hello @Puukka I just tested this behaviour on my end and can confirm the same PITCH UP when engaging AP and close to selected ALT.

Thank you for the report and the videos. I raised the Q into the test group and also made an entry into our tracking list.

 

Will keep you posted.

 

First of all I'm very happy about the last updates, it's a big pleasure to fly manually, very stable, control inputs feel very realistic, throttle management much easier than before,...I'd say the best plane regarding flying manually I've ever had at the PC. No need for any fine tuning at my side.

 

I only wanted to put this issue in the mind again, catches me often because when enjoying flying manually near 1000ft below the first constraint or even stabilized at cruise altitude, engaging AP gives me a very bad lift and I have to fight to get it at the altitude back again.

Regards, Herbert

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I've had a similar issue since the latest update. And I've also had a problem at cruise as the aircraft gradually pitches up and slows down until it cannot maintain altitude. I've had this experience at altitudes above FL300 and at max thrust. There is no icing. Recently I needed to fly by hand until on approach when the AP was able to track the heading and GS well.

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  • 4 weeks later...

I too have the same problem. I like to manually fly the aircraft to above 10.000ft. The FD is set to the current speed (290) and the aircraft is properly trimmed. Whenever I engage the autopilot, pitch is immediately trimmed up and I loose about 50 knots.

The problem is less pronounced when enganging the AP early. Is there another workaround to allow longer handflying?

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vor 38 Minuten, Mathijs Kok sagte:

We'll do some tests this weekend.

Great, thanks for this info.

For me the only annoying bug left, when handflying for a longer period and after engaging the AP regulary fighting and struggling to get it back to the altitude set. Didn't find any workaround yet, except engaging AP soon after takeoff.

Regards, Herbert

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4 hours ago, Puukka said:

Great, thanks for this info.

For me the only annoying bug left, when handflying for a longer period and after engaging the AP regulary fighting and struggling to get it back to the altitude set. Didn't find any workaround yet, except engaging AP soon after takeoff.

Regards, Herbert

As noted in another thread I have seen something like this twice, however only after having reached and flown for some time at cruise.  Both times it occurred during a sudden and drastic change from head wind to tail wind and both times it resulted in leveling out at a lower altitude, recycling the AP (hit the bar). 

 

On every flight, weather permitting,  I hand fly to 10,000 feet and only engage the autopilot when  I reach a pitch stable 290 knot speed.  In fact the last time this occurred I engaged the AP very early because of local weather, so it had nothing to do with when the AP was engaged.  I believe that some glitchy wx is injected by MSFS because once I hand fly out of the issue about 50 or so nm I find that I can recycle the AP and climb back to cruise and continue like nothing happened. 

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I just tried it again:

EDLP runway 24, clear skies

250 to FL100, then 290 knots. The flightdirector was set to speed with those speeds set. I engaged the AP passing FL150. which resulted in a stall.

I tested if the weight has an influence on it, but it did not:

A TOW of 22.5 tons resulted in a trim change from 1.4 to 5.7. The result for a TOW of 30 tons was the same, a trim of 2.6 was changed to 5.6.

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vor 6 Stunden , Mathijs Kok sagte:

There has to be another factor though as it works for me.  Could you try with zero weather? See if that has an influence?

 

Strange. Just tried also with no weather, same result.

At this thread GEK_the_Reaper experienced same issue and took it to the tracking list:

 

On 10.4.2021 at 10:28, GEK_the_Reaper sagte:

Hello @Puukka I just tested this behaviour on my end and can confirm the same PITCH UP when engaging AP and close to selected ALT.

Thank you for the report and the videos. I raised the Q into the test group and also made an entry into our tracking list.

 

Will keep you posted.

I use standard weight and fuel, It´s also every time when flying to my first altitute I´ve set, as example here stabilized at 5000ft, engaging AP sets the trim apruptly to 5.1 than slowly reducing to 3.4.

 

 

Here´s the video showing the issue 700ft before reaching the selected altitude.

 

 

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On 1.7.2021 at 12:09, falcon55 sagte:

I too have the same problem. I like to manually fly the aircraft to above 10.000ft. The FD is set to the current speed (290) and the aircraft is properly trimmed. Whenever I engage the autopilot, pitch is immediately trimmed up and I loose about 50 knots.

The problem is less pronounced when enganging the AP early. Is there another workaround to allow longer handflying?

The only workaround I use is, after engaging the AP and the plane starting it´s rocket climb, pushing the yoke gently against, till the climb get´s to a normal rate.

This works often for me but also needs about 2000ft. 

Regards,

Herbert

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