The pilot under instruction was flying a practice power-off 180° maneuver from the downwind leg at the accident airport. The flight instructor stated that on final approach the airplane’s airspeed was slow and the flight path was low. He stated that since the purpose of the flight was to evaluate student’s piloting skills, he allowed the approach to proceed and did not tell the student to add power or go around. The airplane landed firmly at the runway threshold and the horizontal stabilizer impacted a runway threshold light. Postaccident examination revealed that the horizontal stabilizer sustained substantial damage. The flight instructor reported that there were no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation and that a go-around maneuver should have been initiated when the approach became unstable.