correct as is Hornet Autopilot R-ALT mode disengages itself after climbs

[Tom Kazansky]

DCS 2.7.11.22211 (stable)

Hornet's autopilot in radar altitude mode disengages istself when AP tries to push the nose down to level after climbs. Makes it useless, imho.

I encountered this in low level flights and found it not too unexpected. It is obviously not a terrain following radar, but at over 4000 ft it should not happen.

This very short track shows the issue several times within a very short period of time. I turn the R-ALT mode on several times but it disengages as AP tries to push the nose down after climbing.

Hint: this is not a joystick-deadzone or input issue. It even happens when I set my deadzones to 100 (=dead stick).

It happens not only in Caucasus.

1.) Is this a known issue?

2.) Are there no audio warnings in the real Hornet when AP disengages (or enters ctrl-steering mode)?

FA-18C 2.7.11 AP R-ALT disengages Caucasus 01.trk

[BIGNEWY]

As you mention it is not a terrain following AP, you are using RADAR Alt in uneven terrain, the autopilot reaches its limits. 

If you have any evidence the behaviour is different feel free to PM me. 

thanks

[Tom Kazansky]

Thanks for looking into this.

I could live with that answer if it not only occured on pushes of the nose. It seems obvious that such a AP mode can't avoid a wall-like mountain but it only occurs when the AP tries to get back to level flight. Imho, it could do this within whatever limits it is able to put the nose back down. I don't see a reason, that a push after climb should be executed by AP so hard that it breaks the limits.

I will try to find another terrain, thas is close to flat.

And in addition: the R-ALT mode worked in those conditions like in my track before, some months ago.

I'll be back...

 

[Tom Kazansky]

Here is an example of two AP disengagements in one track.

the first at mission time +18s occurs over a much lower hill.

the one at +49s comes very unexpected.

I will see if I get more of those surprising ones on flatter tarrain.

 

FA-18C 2.7.11 AP R-ALT disengages Caucasus 02.trk

[Tom Kazansky]

another one with even flatter terrain.

what strikes me, is the exact moment when AP disengages. It is not when the climb rates, descent rates or the G-forces are at max. It is after those changes.

@19s after reaching a climb (for a brief moment).

@33s after the change to a descent.

If those terrains are already outside of any NATOPS limits for this AP-mode, it is ok for me. but I still don't see a reason, why R-ALT mode stays engaged while 3G+ pulls and disengages after that when coming back to 1 G.

 

FA-18C 2.7.11 AP R-ALT disengages Caucasus 04.trk

[BIGNEWY]

I have checked with the team, this is the intended behaviour. If you have evidence it should be different please PM me. 

thank you

[Tom Kazansky]

thank you for checking.