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Dirtyfeet

Autopilot altitude mode

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Hi, i'm sure it's my fault but i don't get the rocker in the middle of the yokes to work. I set the desired altitude, let's say 5000 feet, activate autopilot in nav and alt mode and set the fd in alt alert mode. If try now to change the rate of climb through the mentioned rocker nothing happens. I see the animation but it changes nothing. Maybe somebody has a hint for me. Thanks and kind regards

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ALT mode will hold altitude.

Turn off (or do not activate) ALT mode, and do everything else as you described... when you reach the selected altitude,

the autopilot will capture and set ALT mode.

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Hi Bert, thank you for your answer. Ohhh stupid me..... so logical but i don't get it.... thanks

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The odd thing happens when I select Altitude mode , the plane pitches up severly ( 2000 to 4000fpm) for about 600 feet, then levels off and returns (descneds 500fpm) to the selected altitude. I fly the plane to about 100ft per min and have the plane trimmed before selecting altitude mode. Did I miss something?

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Yes. Set the altimeter correctly. Set the CG correctly. Especially the latter.

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The odd thing happens when I select Altitude mode , the plane pitches up severly ( 2000 to 4000fpm) for about 600 feet, then levels off and returns (descneds 500fpm) to the selected altitude. I fly the plane to about 100ft per min and have the plane trimmed before selecting altitude mode. Did I miss something?

No, it seems you didn't. If the situation is exactly like you've described, is one of AP issues that are being revised.

Tom

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Oh goody. Contention.

One of us is right. The other is wrong,

I have absolutely no problems making the a/p work. It does NONE of the things you describe because I know how to make it work.

Obviously, if it was a fundamental problem with the a/p I'd have the problem, same as you.

I don't.

Guess who's right...

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Oh, good for you then because:

1) You have absolutely no problems with the autopilot.

2) You know how to make it work. Amazing!

And of course there is no fundamental problem with the autopilot, only a bunch of issues Finn is already working on. That's all I can say for the moment.

Tom.

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I am working on AP issues, but please note that the ALT hold function used is the standard FSX function.

What I often miss in thise reprots are detailed description on how exactly You operate the AP functions i.e is it simply pressing the ALT button without or with the ALT ALRT active ??

A detailed description could look like this:

-Steady trimmed climb

-AP On

-IAS hold On

-Climb with 1500 ft/min

-Initial altitude 2000 ft

-Altitude Alert setting= 5000 ft

-ALT ALRT active

I simply need to know all settings like starting altitude/attitude, target altitude, modes active etc etc..

I have made quite a few fixes and enhancements to both the autopilot anf flight director that now needs to be tested by the beta testers.

But Snave is still right that the aircraft needs to be loaded within it´s CG limits, cause the autopilot has to oerate within the same limits as if the pilot where flying it. At least You should be able to manually trim the aircraft within normal flight attitudes without getting too close to the trim limits.

Finn

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I just got back tonight and I will go through adjusting the CG forward to see if that improves the pitch up, although one thing comes to mind, the aircraft has been trimmed out. There is no reason for the autopilot to pull back abruptly when engaged with alt hold. Anyway, testing tomorrow.

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When you understand how trim works (badly) in FSX, you will understand why CG is so crucial.

As this has been explained several times in the forum for this and other aircraft, I don't propose to repeat myself. I don't propose to repeat myself. :glare_s:

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Would it be a suggestion to use the ’Fuel Planner / Load Manager’ to eliminate the “center of gravity” issue/question?

I am assuming here that the provided ’Fuel Planner / Load Manager’ would balance the fuel, passengers and load within the forward and aft tolerance of the C of G.

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I tested different load configurations using the Fuel Manager and didn't find any problem. The a/c was proportionally loaded, so I assume its CoG always fell within the limits.
I also manually loaded the Twottet with CoG way outside of the CoG (ie 700 lbs on the back cargo section, with no passengers), and even with an overweight of 650 pounds, in all cases I was able to take off and fly the aircraft manually and, once stabilized, use the autopilot to maintain the flight under control. Interesting to see that in the OW situation FS crashed when flying leveled and AP ALT commanded, showing a "aircraft structure overstressed!" or alike message.
All this said, Finn's comment regarding an aircraft operating on its CoG limits should be able to fly either by pilot or autopilot control is absolutely true.
Also Snave's comment on FS ap trim is right as well, though not being a trim's specifically problem but the fact that, as FS ap does not control the elevators, pitch is handled exclusively by operating the elevator trim. As a result, abrupt changes in pitch may happen when the ap is engaged in an out-of-proper trim situation.
Off (or near off) CoG limits will make things worst BUT, once stabilized in the current attitude, the AP should be able to control the flight without oscillations.
And turning the AP off or in a pitch hold mode should not affect the flight path because the elevator trim is maintaining the attitude.
Oscillation is a product of overshooting, something that is strongly related to programming code. And is one of the most difficult issues both FS and real ap control programs have to deal with.
Tom

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There's an amended autopilot tweak with an improved pitch section coming out in the next update (1.02). It was provided to the beta testers on Friday and tested over the weekend with very good results. I gave it a good workout myself and am very happy with it. Given the feedback I've seen by the other testers, I don't think it will be long before it's released.

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There's an amended autopilot tweak with an improved pitch section coming out in the next update (1.02). It was provided to the beta testers on Friday and tested over the weekend with very good results. I gave it a good workout myself and am very happy with it. Given the feedback I've seen by the other testers, I don't think it will be long before it's released.

Yes.... but..... it is still good practise to hand over a well trimmed aircraft to George the AutoPilot. You passengers will appreciate it.

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Looking forward to the tweak. I have no severe issues but maybe one or two things will be more smooth :) Offline I dont need an autopilot but I noticed that on Vatsim it is sometimes really needed.

Another thing I noticed (not a bug) when using GoFlight modules and using the Alt hold mode then it is not working like the Alt hold in the VC. When using the button in the VC the altitude is getting set to the current alt and alt hold is engaged. When using the GoFlight button Alt mode will be engaged but it tries to reach the set alltitude (which is zero). I was irritated at first but now after I have figured out I wanted to let you know (in case there are other GoFlight users).

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Yes.... but..... it is still good practise to hand over a well trimmed aircraft to George the AutoPilot. You passengers will appreciate it.

Right you are, Mathijs. Handing off to your First Officer or George, or indeed, just flying by yourself, always be in trim.

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