A flight instructor and a new-hire trainee pilot were practicing instrument approach procedures in the multi-engine airplane. The first approach was a circle-to-land that terminated with a go-around/rejected landing. On climb out, the flight instructor reduced power on the left engine to simulate an engine failure on takeoff. The pilot then ran the memory items for an engine failure, which included turning the left engine auxiliary fuel boost pump to high. Air traffic control then vectored the airplane for another instrument approach. The approach terminated with the pilot making visual contact with the runway and preparing to land. When the airplane was about 50 ft above the runway, the flight instructor called for a two-engine go-around. The pilot brought both throttles to full power and retracted the flaps and gear. The flight instructor said the airplane yawed left, and the airspeed was about 80 knots, well under the airplane’s best single engine rate of climb speed of 95 knots. The flight instructor took control of the airplane and called for the gear to be extended. He told the pilot that he was going to land on the grass. The airplane landed hard and rolled before the nose and left main landing gear collapsed, resulting in substantial damage to the left engine and wing. Prior to exiting the airplane, the pilot said he turned the left engine auxiliary boost pump from the high position to the off position. The flight instructor said that turning the boost pump to high while the engine was still operating could flood the engine with excess fuel and cause it to lose power. He said that he normally reminds pilots not to turn the pump to high during a simulated engine failure in flight, but neither he nor the pilot recalled it being mentioned during the accident flight. Postaccident examination of the left engine revealed no mechanical discrepancies that would have precluded normal operation. As a result, its most likely that when the boost pump was turned to high, it flooded the engine with excess fuel, resulting in loss of engine power while attempting to go around. The flight instructor and the pilot were not prepared for the loss of engine power and the airspeed dropped well below the airplane’s best single engine rate of climb speed of 95 knots. Due to the low airspeed and altitude, the flight instructor took control of the airplane and landed on the grass adjacent to the runway. The pilot said that he had practiced simulated engine out procedures in the simulator, but never in the airplane. In the simulator, he was taught to physically move the auxiliary boost pump to the high position when practicing a simulated engine failure. He was not aware that turning the auxiliary fuel boost pump to high could result in a loss of engine power.