Auto Pilot and stalls

[Chris@YYZ]

ok, this morning I was flying LAX-YVR in a 777, on approach, (APP mode and autopilot engaged) for no apparent reason my nose pitched up to 55 degrees and I stalled. I temporarly recovered, but when I tried to pull my nose back to level, I stalled again. I was going 160 KIAS with flaps at 25, which according to the checklist I have is normal approach procedure.

This has also happened on other ocasions and not always on approach, sometimes on climbout, and sometimes at FL330.

Does anyone know why this happens?

[Chris@YYZ]

anyone?

[Airbus_A320]

Some sort of bug mabey. I mean if you do everything right and it even happens at FL330, that sounds like some sort of bug.

[RingwaySam]

Hmm...Sometimes does it to me

[Crazy764]

If you are on final approach, and you are very close to the runway, a few of the autopilot lights will disengage automatically. At that time, quickly turn off all remaining AP and fly the final stretch yourself. Otherwise, the plane will try to maintain a certain speed or altitude or whatnot (can't remember exactly, since I fly my approaches manually).

If you are at FL330, make sure your VS isn't set too high. As you get higher, it's harder for the plane to climb. At that altitude, your VS should be 500 or less.

Remember, the autopilot will try to achieve all your inputted data. But if they are impossible, then the plane will stall.

[MD11Forever]

If you are on final approach, and you are very close to the runway, a few of the autopilot lights will disengage automatically. At that time, quickly turn off all remaining AP and fly the final stretch yourself. Otherwise, the plane will try to maintain a certain speed or altitude or whatnot (can't remember exactly, since I fly my approaches manually).

If you are at FL330, make sure your VS isn't set too high. As you get higher, it's harder for the plane to climb. At that altitude, your VS should be 500 or less.

Remember, the autopilot will try to achieve all your inputted data. But if they are impossible, then the plane will stall.

What Will says is true, although I have never had the issues he mentions on final approach and can let the autopilot fly right to the threshold if I want...at that point I simply cut the autopilot off totally, chop the throttles, and flare for touchdown. Works like a champ.