747-8 Gone Crazy

Alright.

I’m on final at KLAX RWY 25L and suddenly my 747-8F goes crazy and pitches up and down at a crazy rate.

When I try to stabilize it with necessary trim, it starts nose-diving, even though I set trim to +100%

Despite not stalling (IAS 160kts), the plane falls to the ground, but without crashing and a warning of a speed violation, so I just quit immediately.

Has anyone experiences this issue or is this a first?

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There’s a lot of variables at play. Weight, flaps, speed, were you using APPR, etc.

There was no APPR available. The 747-8 wasn’t equipped with it.

I was also well under MLW and was at 190kts before the fall.

Did you just turn off AP? Or were you flying manual all the way?

Uhh…

Well, before turning off A/P, the nose was moderately bobbing but nearing 3000ft to prepare myself was a nightmare because the plane would often descend at a toxic vs (-3000 +). Then I tried to handle this manually and without surprise in this situation the nose dived a bit but suddenly it went very down. And despite all my attempts to bring it back up, the plane did not budge one bit .

What flaps setting were you using?

I was using Flaps 10 for IAS 180-190 kts. A bit too quick?

You said you were at 160KIAS when this happened. What flap settings at this speed?

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Oh sorry let me try to remember as much as possible.

Ok, I know that the plane remained at Flaps 10 the whole time.

The airspeed was constantly adjusted from 180 or 190 to 160 and back to counteract the dive.

Sorry m8 that’s all I can really remember clearly

What happened is you stalled. You should have flaps 20+ at 160 Knots. That’s why you were bobbing

maybe you could share your replay :-)

When disconnecting autopilot did you recalibrate this might be what caused the pitch down.

I recalibrated at the start of the flight but not anywhere else.

let me check the replay

Yeah it’s advised to calibrate the device before you disconnect the AP

Well I was using a joystick

Ok I went through the replay and came up with a conclusion.

It appears @Chatta290 was correct. I was stalling at 160 kts with Flaps 10 but this was only seconds before the ground slam.’

Apart from that, the plane was never below 180 kts before the stall.

So…

just get more flaps below 180kts? @Chatta290 I might need some assistance.

Yes 20 flaps once below 180 knots.

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The slower you fly, as for an instance when upon landing, you add higher degrees of flaps when your speed decreases. This is done to increase lift.m, to keep staying airborne.

When you are slower, you are required to have a higher flaps setting to have air under the wings that will keep you up in the air and not fall down flat or stall in anyway.

So when you’re below 180kts and going towards 160kts in a 747 of any type, you should have 20-25 flaps then if needed 30 at 150kts and below.

I usually land the 747-8 at 145-155kts with 25-30 flaps settings. 25 or 30 will depend on various factors such as winds, weight, etc…

Alright. Someone can close this topic