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Nathan3219

Plane unable to hold altitude

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Whenever I try to capture an altitude, the plane overshoots and undershoots the altitude repeatedly, getting more aggressive each time it tries to capture the altitude.


Currently I am in the sim watching my plane try to capture 5,500 ft. It is currently at 11,000 feet after an 11,000FPM climb and it is now entering a deep dive (-8,000FPM) to reacquire the altitude.

This has been repeatedly happening in both the CRJ-700 and CRJ-900 and as much as I love this aircraft, this issue makes flying with the autopilot unreliable in this flight it stalled me at 10,000 feet after a near vertical climb while I was trying to capture 5,500 feet and the last flight I did (KBUF-KEWR) it tried to dive me into the ground during approach and I had to manually yank the stick to prevent from crashing.

 

Update: the plane made contact with terrain at -11,000FPM.

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I never had this. However, there's one issue which can lead to autopilot modes disconnecting. This is due to a change in the mouse handling by P3D 4.4 (and only 4.4!). It can happen that after pressing a pushbutton the next mouseclick presses the button again. For example, if you switch on ALT then click somewhere else (even free space), ALT is switched off again. This could cause the effect that you're describing.

 

This only concerns pushbuttons, no other controls. As a temporary workaround (until our modeller is back from vacation and we can release a fix), just press the right mouse button after clicking any pushbutton. This will cancel the "armed" left button.

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24 minutes ago, Hans Hartmann said:

I never had this. However, there's one issue which can lead to autopilot modes disconnecting. This is due to a change in the mouse handling by P3D 4.4 (and only 4.4!). It can happen that after pressing a pushbutton the next mouseclick presses the button again. For example, if you switch on ALT then click somewhere else (even free space), ALT is switched off again. This could cause the effect that you're describing.

 

This only concerns pushbuttons, no other controls. As a temporary workaround (until our modeller is back from vacation and we can release a fix), just press the right mouse button after clicking any pushbutton. This will cancel the "armed" left button.

 

I'm on FSX:SE so I dont believe this is the culprit, however I will record a video in the morning if I can recreate it to show it in better detail!

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What's the elevator trim when that happens? A screenshot of the DAVE payload page might be helpful too.

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I understand @maxhades question - I didn't even know that the CRJ´s can reach 11000ft in the climb 😎

 

No, seriously, I did not meet such a behavior of the CRJ´s yet.
I would say, your descriptions sound to me like not complete basic configuration (weight, fuel, trim etc.) and/or wrong autopilot settings.

 

You know that the CRJ´s doesn't have an autothrust like the B737, A320, B777 etc?

A screenshot of the instruments at take off would be helpful too.

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I think it has to do with climbing to a very low altitude at a very high VS. Something like CLB150 where the aircraft climbs like a rocket and the autopilot has zero chance to capture the altitude.

The result of that would be a full trim down to capture the altitude, followed by an overshoot below the selected altitude, full trim up, overshoot, full trim down, overshoot and so on. There are operational limits to what an autopilot can capture. It would eventually but there's not enough room between aircraft and ground in this case.

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10 hours ago, Hans Hartmann said:

I think it has to do with climbing to a very low altitude at a very high VS. Something like CLB150 where the aircraft climbs like a rocket and the autopilot has zero chance to capture the altitude.

The result of that would be a full trim down to capture the altitude, followed by an overshoot below the selected altitude, full trim up, overshoot, full trim down, overshoot and so on. There are operational limits to what an autopilot can capture. It would eventually but there's not enough room between aircraft and ground in this case.

 

Hans,

After some experimenting tonight I have found that I believe the issue is with Air Hauler 2, and is not any issue I am having with the aircraft. Failure to use DAVE or the CRJ manager AFTER Air Hauler 2 either connects to FSX or loads you in your plane, results in AH2 loading the aircraft with different methods, resulting in improper load and CG. Say, for example Air Hauler 2 decides to put ALL your payload in "PAX F" section on the default Payload Settings (which obviously should not be used anyways) would create tremendous inbalance and cause the plane and its systems to cease to function properly.

 

This would also explain why this is an issue that only happens on occasion with me, because usually I remember to use DAVE/CRJ Manager AFTER AH2 connects to my sim, but occasionally if I am in a hurry I may forget, thus setting up a situation with improper load and balance.

 

So if anyone else has this problem and stumbles upon this thread, if you are using AH2 or another external program similar to it, be sure to use DAVE/CRJ Manager AFTER Air Hauler 2 puts you in the aircraft, and the same logic should be applied to all other complex addons as well since I'm sure this isn't the only plane that will get wacky in such a situation.

 

Anyways love the plane, and time for me to get off the boards and back into my CRJ!😃

 

Thanks for the help all.

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Because we believe this topic has been answered we have closed it. If you have any more questions feel free to open a new topic.

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