At 1359 Pacific time, a Cessna 414 crashed after losing engine power while on approach to runway 31L at Palm Springs International Airport. The flight instructor and one passenger suffered minor injuries, and the multiengine-rated pilot in the left seat suffered serious injuries. The passenger and left-seat pilot had just purchased the airplane and the instructor was giving them transition training. The instructor noted that when they inspected the airplane the day before the accident, the left alternator circuit breaker was open. It was reset without incident. Prior to the accident flight, the pilots drained one quart of cloudy water and sediment from one of the fuel tanks on the right wing. On the accident flight, the airplane was cruising at FL250 when the instructor switched from the main fuel tanks to the auxiliary. At that point, the left engine failed. They began a descent toward and airport and moved the fuel selector back to the main tanks and the engine restarted. They elected to continue the flight and conducted air work. As they descended to refuel and change pilots, they decided to conduct a simulated single-engine approach and the instructor failed the left engine. During the base to final turn, the left engine began to surge and the airplane went off course. The instructor took control and advanced the left engine throttle, which caused the surging to increase. At the same time, the power on the right engine began to degrade. The airplane landed hard in a ravine.