Woops wrong should have been 1 to 2nm
FCTM rev11
When a manual landing is planned from an approach with the autopilot
connected, the transition to manual flight should be planned early enough
to allow the pilot time to establish airplane control before beginning the
flare. The PF should consider disengaging the autopilot and disconnecting
the autothrottle 1 to 2 nm before the threshold, or approximately 300 to 600
feet above field elevation.