Background
The incident occurred during a night training flight involving an instructor pilot and a student pilot. The flight was conducting a single-engine approach and landing.
Sequence of Events
The student pilot was flying the approach under the supervision of the instructor. As the airplane progressed to a short final, the instructor perceived that the student was over-controlling the aircraft. The instructor then assumed control of the airplane.
Deciding to abort the landing, the instructor initiated a go-around and instructed the student pilot to advance the throttles. However, the instructor did not verify that the throttles had actually been advanced by the student. During the go-around, the airplane lost directional control when VMC (minimum control speed with one engine inoperative) was not maintained.
Probable Cause
The probable cause was the instructor pilot's failure to verify that the throttles had been advanced during the go-around, and the subsequent failure to maintain VMC, which led to a loss of control.