Deadhead
You seem to be having trouble with your compass as well as falling off your broom stick. By the way if you taxi at 90 knots you'll get the same effect on the ground I promise.
The compass needle is pivoted north of the c of g to counteract dip thus when subject to a turning acceleration this causes a deflection of the needle. On South the pivot point is effectively on the opposite side of the C of G i.e. its still North of it and the deflection is in the opposite direction. Fore and aft acceleration on North and South just cause the needle to rise or dip, on East or West the angular acceleration does not cause a turning moment but a speed change will.
I think you should practice a lecture on the effects of coreolis on the compass for your next renewal.