disconnecting autopilot, nose dive

Hi,

À very annoying issue happened to me as I disconnected autopilot on final approach. The nose started to dive (trim set on 0). I had calibrated my pad at the beginning of the flight, but it completely ruined the experience.

Has anyone ever experienced this? Any tips on how to avoid it?

Thanks

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Did you change your ipad’s position in-flight?

You need to have the aircraft set up correctly. Correct trim correct speed correct flaps and it won’t do that. Same with when you engage it. This might help

@koukkey… Check your Weight and Balance my boy! Did’t ID you aircraft but appears your center of gravity is all screwed up with a fwd loading. Do a Pre Flight always. Set up before you launch. Always check your fuel and cargo loading no matter what you fly! Merry Xmas, Mas Sends

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Yes i had these problems but you should calibrate before disconnecting autopilot and then you can land

It has everything to do with your trim. The reason the nose dives down is because the elevators flip back to the zero position before resuming the new position.

Moving the trim changes the reset position of your elevators to match the position of your elevators during approach.
The only way to match the position is through trial and error.

To do this, go to solo landing and move your trim up until the dip disappears when disengaging the auto VS. Remember/note the position, weight and type of aircraft. It’s a good practice to use the same weight for all your landings.

And remember to calibrate before disengaging the auto VS.

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I assume you’re new to IF and the forum, so welcome.

The nose dive happens because when you activate the A/P, your elevators assume a different position rather than the neutral when before activating it, so they’ll rapidly go back to that position when turning off the A/P.

To counteract this, use the TRIM. IRL they ease the pressure the pilot needs to make on the yoke to keep the nose of the plane up.
The benefits of this are that you won’t need to recalibrate if you remember more or less your original device possition when you began playing.

For example, on the Boeing 737-700/800, I use 28% of trim and push my phone down to avoid having my plane go up (I’ll have to revise that number, try 27%), the 747-400 needs 17% and the 717 uses 20%. The A318, although it doesn’t have the nose dive, uses a 5% trim to have a nice transition.
All of these planes use Normal weight, and IRL they don’t nose dive.

Hope this helps.

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In spanish they are also called “timones de profundidad”, so “depth ailerons” would be the literal translation.

That is really mean. He is just correcting your mistake.

Maybe I got the wrong way around how he was correcting my error.

I’ll shove the throttle from 100% to 0%, and in planes like a 717-200 and a CRJ-200, my plane will just make a complete backflip. This is different than your problem, but how is this caused? Autopilot on the vertical speed, altitude, and heading. I have full flaps and armed spoilers, and trim at 0. Need to set the trim, or disengage autopilot?

Because when you slow down, the plane will lose altitude, and the A/P will start raising the nose so as to keep the selected altitude. As a consequence, as the A/P acts, you lose speed and stall or, if you are high enough, roll over and recover.

And you need to use the flaps at the right speed.

There is a simple answer. Press calibrate before you DC the autopilot

And where’s the fun on that? Using the trim will avoid the recalibration.

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You will still have to calibrate.

No if you remember the position of the phone of the first calibration.
At least that’s for me.

Before I disconnect the AP I always recalibrate my iPad first to avoid that issue.

Happy Contrails

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Hi all,

Thanks. I still need to get a hang of it. It would a opera as though a little calibration is needed before I disconnect. I chèche weights and they’re all fine. But it would apear as though the diving continues if I increase flaps. This only seems to occur with 777-300.