Type CS763ER-PW and I found something wrong with the A/T system.I was making the final approach and everything's normal at first,but the A/T abnormally increased the power at about 1100ft and accelerated to 150+kt,which caused A/P nose-down to chase the glide slope.
Vref 139kt with Flap30,speedbrake armed before the question happened.
Could someone help me solve this problem or is this a bug?Thanks very much.