Palm Springs Regional Airport
Aircraft Accident/Incident Report

Palm Springs, California 92262
Tuesady, January 14, 2003 13:59 PST

The certificated flight instructor (CFI) was providing multiengine training to one of the two owner/pilots aboard during an IFR cross-country flight. Upon reaching cruise altitude, both left and right engine fuel selectors were turned from the main fuel tanks to the auxiliary tanks. Shortly after selecting the auxiliary tanks, the left engine lost power. Power was restored after the fuel selector was returned to the main tank, and the CFI elected to continue the flight. During approach to land at the destination airport, the CFI simulated a left engine failure by reducing power on that engine to "zero thrust." The left propeller was intentionally not feathered. While on the base leg, about to turn final, the left engine began to surge, pulling the airplane away from the airport. The CFI stated that he took the controls, and increased power on both engines, but the airplane continued to move away from the runway. He stated that the left engine continued to surge, and the right engine began to lose power. He indicated that he turned the boost pumps for both engines from the low to "ON" (high) position without any noticeable difference in power. He did not feather either propeller, and made a forced landing off airport in a sandy ravine. All pilots indicated that there was ample fuel aboard the airplane at the time of the engine problems, and that the fuel tank selectors were on the main tanks. Postaccident inspection disclosed that the left main and auxiliary fuel tanks had been breached during the accident. The right main and auxiliary tanks were intact, with a usable quantity of fuel remaining in the right main. The left engine had damage that precluded a test run. It was disassembled, and no evidence of any preimpact mechanical anomaly was discovered. The left engine driven fuel pump was not tested. The left engine's fuel boost pump ran noisily for a short period, and then overheated. The right engine was successfully run on a test stand. An inspection of the right engine's spark plugs prior to the engine run revealed that the engine had operated in an overly rich state just prior to the accident. The right engine's fuel boost pump functioned normally. The airplane's flight manual cautions that if the boost pump switch is moved to the high position while the engine driven fuel pump is operating, an overly rich condition may result in a total loss of engine power.

The flight instructor's improper selection of the high boost position for the operating right engine while on base leg to land, which resulted in a loss of engine power of the right engine. Factors associated with the accident are the left engine's loss of power for an undetermined reason, the flight instructor's failure to feather the propellers of the affected engines, and his failure to maintain directional control, which resulted in an off-airport forced landing.