Something odd happened on autopilot yesterday...

[greenhorn]

Hi all,

I was flying the BAE 146 Avroliner (the red one in the gambling livery) north over the UK at 26000 ft.  Air pressure was 3020mb, I was cruising at 300kts IAS on autopilot (with NAV switched on - basically the plane was flying itself  8-))

All of a sudden, the plane started swinging wildly across the sky, porpoising through 2000ft or so, and swinging through 90* left to right and more, basically it got so bad I had to disengage autopilot and drop down 10000ft before the wing stalled.  Very odd.

I was using the 15min update real-life weather, it was cold and fairly windy, pressure was as I said earlier.  Basically, was this just a glitch, or something I was doing wrong?  As a last resort before dropping out of autopilot and descending I switched on the Yaw Dampener, but it had no effect.

Thanks for replies, I'd like to know what killed my 80 or so passengers

Cheers

Seb

[MattNW]

Icing maybe?

[Wii]

Did you have autothrottle on?

[greenhorn]

Autothrottle, Flight Direction, Altitude Hold, NAV, the entire autopilot basically, was on.

[Ashar]

It's FS

[Brett_Henderson]

Sounds like you encountered a massive wind shift... and the autopilot got into an "overcorrect/undercorrect" cycle.. It's happened to me before. A large change in wind will bring on large corrections by the autopilot (both pitch and throttle) and if the wind shifts back quickly, you've got a doubled effect for a period of time...

[beaky]

When in doubt, disengage that AP! Same applies in RL...

[greenhorn]

Thanks guys, I didn't think it was me

As a point of interest, as I was descending in manual control the aircraft was still getting blown around quite a lot so maybe it was a glitch in the wind engine.

Cheers

Seb