Motors keep spinning even when throttle is zero

Recently built a f450 quad copter. When I arm it using my flysky FS i6 transmitter it’s motor starts to spin which is fine. But when I put the throttle to zero it still keeps on spinning. When I try to disarm it, it doesn’t disarm and the motors still goes on spinning. Plz help me as soon as possible. Thanks in advance for everyone.
I am attaching a YouTube link. This is not my quadcopter which is shown in the video but I am facing the same problem. I am using APM 2.8 as my flight controller. And ia6b as my reciever.

Have you done the radio calibration successfully ?

Yes done the radio calibration as well as esc calibration successfully

Hi, iam not an expert.
So, you can arm, but can’t disarm. In which flight mode ?. Give more details, so that some experts can help

In Every flight mode I am not able to dis arm.

Check the Left Yaw course endpoint (and trim at zero) on your RC. I may be too high and not allow disarm.

Marc

I am new to this. And I don’t know how to trim the left lawn to zero. Can you plz tell me how I can. And I request plz explain completely and properly. Thanks in advance.

Sorry,

The way to do that is explained in your Radio user manual.

Marc

I have checked that the trimmings were fine. Is there any other way ??? Plz help

Can you please post a flight log from the copter to better enable us to see what is going on.

I’m having the same issue and it started since I upgraded to Copter-3.6.1. In my case I have the flight controller Pixhawk 2.4.8. Is it related to the latest upgrade?