Magnetic interference

[debay777]

Will the metal screws on my tricopter impede the magnometer? I see so many quads and tri's with the FCB right over or directly next to screws but then to calibrate the magnometer I've read suggestions that you put the copter out away from any metal ... including keysn change, and pocket knives and then you can calibrate it or whatever.

[waltr]

No, even if they have been magnetized they will also be fixed relative to the magnetometer chip so will get cal'ed out.
It is all these other 'movable' items that cause mag issues and this includes the electric current flowing through the wire to the ESC/motors.