HISTORY OF FLIGHT On February 7, 1997, at 1713 hours Pacific standard time, a Cessna 310Q, N10ML, operated by the pilot, experienced a total loss of power in both engines on approach to the Santa Monica Municipal Airport. The pilot made a forced landing on the Rancho Park Golf Course in Los Angeles, California. During the landing the airplane collided with trees and rough terrain. The airplane was substantially damaged. The commercial pilot and the passenger sustained minor injuries. No one on the golf course was injured. Visual meteorological conditions prevailed, and no flight plan was filed for the maintenance test flight which originated from the Santa Monica Municipal Airport about 1615. The pilot reported that he was a part owner of the airplane. Since February 3, 1997, the airplane had been undergoing maintenance. The primary purpose of the accident flight was to break in a new cylinder and to note any discrepancies. The pilot further indicated that before takeoff he had determined that the airplane's main fuel tanks were at least 1/2 full of fuel, and the auxiliary tanks were completely full. The fuel consumption rate averaged 35 gallons per hour. The pilot additionally reported that he allowed the left seated passenger, who also held a commercial pilot certificate, to fly the airplane until the time of the power loss. That event occurred when the airplane was in the downwind leg at the Santa Monica Airport. The pilot reported that he took the controls, identified the left engine as having lost all power, and continued flying the airplane for the duration of the flight. According to the pilot, seconds after the left engine lost power, he turned toward the airport and then the right engine lost all power. The pilot stated that he followed the airplane's emergency check list, no engine power was restored, and he made a forced landing on approach to the airport. AIRCRAFT INFORMATION - TANK CAPACITY & EMERGENCY PROCEDURES The airplane was equipped with four fuel tanks. The two main tanks each have a usable capacity of 50 gallons, and the tanks were attached at the wing tips. The two auxiliary tanks each have a usable capacity of 20 gallons, and the tanks were located in the wings. The Cessna Owner's Manual indicates that if an engine fails during flight, "[t]he fuel selector valve handles should be turned to LEFT MAIN for the left engine and RIGHT MAIN for the right engine, during takeoff, landing, and emergency." In the emergency procedures section of the Owner's Manual information is provided regarding the procedure to follow when an engine fails during flight. In pertinent part, the manual states that "if [the] fuel selector valve is in AUXILIARY TANK position, switch to MAIN TANK and feel for detent." WRECKAGE AND IMPACT INFORMATION The National Transportation Safety Board examined the airplane at the accident site prior to its recovery. The cockpit was observed intact and the wings had remained attached to the fuselage. Neither of the engine's propeller blade assemblies were observed in the feathered position. The nose portion of the fuselage and the right main fuel tank was observed destroyed. On the fairway in the wreckage distribution path, witnesses reported evidence of a fuel odor along with fragments from the separated right main fuel tank. A visual inspection of the wing fuel tanks revealed that the right auxiliary tank was about 3/4 full, and the left auxiliary tank was about 1/4 full. The airplane was not level during the tank examination. The left main tank was found totally empty. Both of the fuel selectors in the cockpit were found positioned to the left main tank. Airplane recovery personnel subsequently reported that when they drained the auxiliary tanks, the right and left tanks contained 6.5 and 5.5 gallons, respectively. The left main tank was confirmed as being devoid of fuel.