N4299CPiper PA-34-220T · 1983

The flight instructor reported that they were conducting a simulated single-engine approach in the multi-engine airplane when the airplane began to yaw to the left. In an effort to regain directional control, he took control of the airplane from the student, and increased power on the left engine while simultaneously decreasing power on the right engine. Although both engines were still operating, he did not apply full power to both engines. The airplane impacted the ground, resulting in substantial damage to the fuselage. The pilot did not report any mechanical malfunctions or anomalies that would have precluded normal operation.