Autopilot bug

I was on aporoach to WSSS when suddenly the plane started turning from left to right. The plane descended by its own (vnav not active) and when I disconnected the autopilot, the plane couldnt lift like it was stalling but the airspeed was fine (160kts). (I couldnt attach a video)

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Did you have the right ILS freq tuned in? What plane were you flying? Can you give us a bit more specs about your flight at the time of the incident?

Did you forget flaps perhaps? What you are descibing actually sounds like a stall.

Could you possibly screen record the replay and upload it as unlisted to your Youttube account and link it to us?

The other option is to use and share the link here :) We can help you spot your mistakes!

I was flying a 777-200F and I didnt use ILS, I just had autopilot on to hold my alttitude, speed and heading

Airspeed and my vertical speed was normal (160kts)

I’ve uploaded it to my ig story @ifnich

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Ah, gave ya a follow, I don’t see it yet :)

What were your flaps set to.

I havent set flaps, i was just about to

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Still uploading

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Hmmm…what was your weight percentage load?

I just viewed it, it seems the turning was because you stalled. You weight looked really heavy, that is most likely the reason why you started decreasing in altitude and speed.

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I agree. No flaps at 160kts is too slow unless you are very very light.

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If you were on an approach and the “Load” status bar at the bottom of the flight information is yellow, I’d climb to 7000ft and do a fuel dump. This is because you were MLW (Max Landing Weight)

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Especially if you above MLW, which you shouldn’t when your landing, you should have started extending flaps around 200kts.

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Idk I usually do like I did today and it usually doesnt happen

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Do you know what your weight percentage was?

You said previously that you were at 160, and you say here you had no flaps. That may have been your problem. When you fly that slowly without any flaps, the autopilot will always have to pitch higher to maintain the same flight profile. It’s called porpoising, where the plane is pitching up and down to stay within your set parameters. Within most live cockpits, there is a slate on the front panel somewhere that tells you your Max Speed for each flap detent. I would try to follow that next time you go in for a landing, and to make sure that your weight is distributed properly. An off-axis center of gravity, even by just a couple hundred pounds/kgs, can make or break a flight. After watching the video, I would just double-check that you didn’t arm an ILS freq. Those bank angles look like they are past the A/P limiter as well. Did you ever disengage A/P to correct the movements? When in doubt, Fly it out


Ok thanks for helping, I’ll keep that in mind next time i fly