Autopilot override - How does it work or needs to be used?

[gulredrel]

Hi,

flying with attitude and altitude hold mode on the plane flies straight and level.

There is the autopilot override button which I've assigned to my stick. Pressing and holding it the two lamps for attitude and altitude hold modes start blinking and I'm able to change course and or altitude.

I now let go of the autopilot override button expecting that the MiG is now holding attitude and altitude with the new parameters (e.g. like in the Mirages).

But the MiG now dives a bit, recovers aggressively back up and goes into a climb.

How do I use the autopilot override? Are my expectations wrong what it should do?!

Only messed around in the S variant currently, hopefully it's the same behaviour for FC A and G too.

Thanks

Jens

[AeriaGloria]

I wouldn’t use attitude and altitude hold mode together. They do different things

[Ironhand]

4 hours ago, AeriaGloria said:

I wouldn’t use attitude and altitude hold mode together. They do different things

Using them together can be handy, if you want to orbit at a certain altitude or something similar. And, in fact, you can't engage ALT HOLD without ATT HOLD engaged. But, to the OP’s point, the override function is now screwed up. Even if you’re careful to re-engage the AFCS at the same airspeed it had been previously engaged, there are often severe oscillations to the point that you’ll lose the aircraft unless you take back manual control. When less severe, it’ll eventually return to stable flight on its own. The only way not to have any bobbing is to remain at the same altitude (when using ATT along with ALT HOLD).

This seems to be a bug, though I haven’t delved into the Russian MiG-29 manuals to see what they say about the AFCS. I doubt, however, that the actual system behaves this way.

Edited May 25 by Ironhand

[gulredrel]

Thanks. These oscillations are huge. So I guess I'll disable attitude hold and than re-engage after being on the new track.

[Ironhand]

18 minutes ago, gulredrel said:

Thanks. These oscillations are huge. So I guess I'll disable attitude hold and than re-engage after being on the new track.

That would probably be easiest, when changing altitude. I suppose, too, that you could select LEVELING mode (LAlt+7, IIRC) first. But that's not really what it's for.

Edited May 25 by Ironhand

[AeriaGloria]

5 hours ago, Ironhand said:

Using them together can be handy, if you want to orbit at a certain altitude or something similar. And, in fact, you can't engage ALT HOLD without ATT HOLD engaged. But, to the OP’s point, the override function is now screwed up. Even if you’re careful to re-engage the AFCS at the same airspeed it had been previously engaged, there are often severe oscillations to the point that you’ll lose the aircraft unless you take back manual control. When less severe, it’ll eventually return to stable flight on its own. The only way not to have any bobbing is to remain at the same altitude (when using ATT along with ALT HOLD).

This seems to be a bug, though I haven’t delved into the Russian MiG-29 manuals to see what they say about the AFCS. I doubt, however, that the actual system behaves this way.

But altitude holds would already hold back in an orbit right? 

5 hours ago, Ironhand said:

Using them together can be handy, if you want to orbit at a certain altitude or something similar. And, in fact, you can't engage ALT HOLD without ATT HOLD engaged. But, to the OP’s point, the override function is now screwed up. Even if you’re careful to re-engage the AFCS at the same airspeed it had been previously engaged, there are often severe oscillations to the point that you’ll lose the aircraft unless you take back manual control. When less severe, it’ll eventually return to stable flight on its own. The only way not to have any bobbing is to remain at the same altitude (when using ATT along with ALT HOLD).

This seems to be a bug, though I haven’t delved into the Russian MiG-29 manuals to see what they say about the AFCS. I doubt, however, that the actual system behaves this way.

And I agree, seems to be a bug. I’ve read all sorts of documents on MiG-29 AFCS and all of them describe ADCS override to act exactly as we expect it. Not too disposed given the oscillations it exhibited in other modes. 

Edited May 25 by AeriaGloria

[Ironhand]

3 hours ago, AeriaGloria said:

But altitude holds would already hold back in an orbit right?…

Not sure what you mean, since altitude hold can’t be engaged in the MiG-29 cockpit unless attitude hold is engaged first. Works that way in the sim and in RL.

[AeriaGloria]

3 hours ago, Ironhand said:

Not sure what you mean, since altitude hold can’t be engaged in the MiG-29 cockpit unless attitude hold is engaged first. Works that way in the sim and in RL.

Guess I have to do some reading!

[Ironhand]

 I knew that was how it worked in the FC3 pit and ED usually mimics reality pretty well unless they have a financial reason not to. So I dove into a manual and that’s how it’s described. That seems to be the way the two missing FC3 “automatic” modes work, too. It’s AT HOLD that makes them “automatic”.