As the title says, my autopilot disconnects randomly during cruise, this has happened already 3 times during a 9 hour flight. Is this a bug?

Hi, @simbambim. If you could give us a little more information...

Acft and XP version, flight details, hardware, plugins, online or offline, etc, etc, etc.

Otherwise, anything said here will be pure guessing.

Oh, attaching your log file would also be very helpful.

Cheers.

JP

Latest X-plane (11.55r2) and aircraft (1.6.16) version, flying on VATSIM RCTP-KSFO.

i7-6700 CPU @ 3.40GHz, 16 GB RAM, GeForce GTX 1060 6GB.

Logitech Extreme 3D Pro joystick and Saitek rudder pedals.

Windows 10 Home 64-bit.

Plugins: X-RAAS, xPilot, Landing Speed.

FS Global Real Weather wx engine.

Log.txt

I've experience some AP disconnects on the A350 and they were always related to very bad weather. 

If you let the plane fly into a storm that is severe enough the AP won't be able to keep the plane flying the FP and will disconnect.

Can this be your case?

I do regular long haul flights in the A350 and AP is very reliable, you can leave the plane alone in comfort as long as the forecasted weather enroute is mild.

I definitely wasn't flying in a storm. I would've noticed that. 😆 The winds may have changed though. Maybe with a weather update. Could this have triggered an autopilot disconnect?

Well, my machine is not slow, see the specs above.

I do check on my plane from time to time but meanwhile I could still crash...

You can see the 3 disconnects here in the altitude spikes.

Usually a sudden wind change causes this. 

I think it may have to do with icing. Though I think I should be falling fast with icing (experienced that, too), I haven't encountered the autopilot disconnect issue since I've been turning on all the anti-ice buttons.

Edited August 7, 20213 yr by simbambim

I'd be surprised to get icing at FL350..

I guess it's possible in X-plane.

After long observations, I think I know what happens. When I reduce thrust after takeoff, I've stopped moving the lever as soon as the LVR CLB stops flashing and it remains, so to say, on the very border between manual thrust and auto thrust. And sometimes, by vibration or something, it will jump back into the manual thrust range and start flashing the LVR CLB at me en-route. I've found the solution is to move the lever further down during climb, not just until the LVR CLB stops flashing but a bit more, that way it is more stable. I hope I've explained it somewhat coherently. 😁

5 hours ago, simbambim said:

After long observations, I think I know what happens. When I reduce thrust after takeoff, I've stopped moving the lever as soon as the LVR CLB stops flashing and it remains, so to say, on the very border between manual thrust and auto thrust. And sometimes, by vibration or something, it will jump back into the manual thrust range and start flashing the LVR CLB at me en-route. I've found the solution is to move the lever further down during climb, not just until the LVR CLB stops flashing but a bit more, that way it is more stable. I hope I've explained it somewhat coherently. 😁

That shouldn't affect the autopilot as it should remain on even with autothrust in the MCT mode. Or did you mean autothrust this whole time?

I mean, I think the autothrust disconnects first, then the speed starts wandering until the autopilot disconnects, then the altitude starts wandering. Is it not a possible explanation?

On 11/29/2021 at 8:17 PM, simbambim said:

I mean, I think the autothrust disconnects first, then the speed starts wandering until the autopilot disconnects, then the altitude starts wandering. Is it not a possible explanation?

If your autothrust disconnects because you're in MAN MCT that shouldn't turn off the autopilot unless your speed exceeded the maximum speed where the red bars on the speed tape are or goes too slow. But then there are loads of things that need fixing with the A350 so could be a bug with it. Never experienced this

This happened to me once, when I noticed zero winds in cruise and realised I did not have ActiveSky running. Loaded AS and got immediate 100kt headwind. Auto-pilot disconnected and plane began rapid descent, basically was unrecoverable, no climb rate at all even at TOGA at lower flight levels, continuous descent towards the ground so I closed XP. It later occured to me it may have been a simulated overspeed damage, but otherwise it may point to deficiencies in FF A350 code-base ie not designed to deal with such extreme airspeed changes.

I just got the aircraft, and as soon as I reach my cruising altitude, my Autopilot goes off and I cant turn it back on.. 

Edited January 30, 20223 yr by Dan Todorov

On 1/31/2022 at 1:07 AM, Dan Todorov said:

I just got the aircraft, and as soon as I reach my cruising altitude, my Autopilot goes off and I cant turn it back on.. 

This also happens to me, and I recently got it too