1) THE FAILURE OF THE PILOT-IN-COMMAND (CFI) TO PROVIDE ADEQUATE SUPERVISION OF THE DUAL STUDENT DURING A SIMULATED SINGLE-ENGINE APPROACH, AND 2) HIS FAILURE TO PERFORM REMEDIAL ACTION. THIS LED TO A LOSS OF AIRCRAFT CONTROL IN CLOSE PROXIMITY TO THE GROUND. CONTRIBUTING TO THE ACCIDENT WAS THE DUAL STUDENT'S FAILURE TO MAINTAIN MINIMUM CONTROLLABLE AIRSPEED AND A PROPER GLIDEPATH TO THE RUNWAY DURING THE APPROACH.