Accident Sequence
While on short final approach to runway 19 right at McCarran Airport, the airplane's engine lost power. The pilot executed a forced landing on a dirt road located approximately one-quarter mile from the runway. The aircraft touched down hard in a 5- to 10-degree bank and skidded to a stop, resulting in substantial damage.
Flight and Fuel Management
The flight originated from El Monte Airport. The pilot initially operated on the left main tank. After consuming 10.1 gallons from that tank, the fuel selector was switched to the auxiliary tank while over Baker, California, roughly halfway between El Monte and Las Vegas. The auxiliary tank was used for the remainder of the flight; the right main tank was not utilized.
As the aircraft approached McCarran for landing, the pilot verified that the fuel selector remained in the auxiliary position and estimated approximately 13 gallons of fuel remaining. The airplane was equipped with a Shadin fuel management system that displayed fuel flow, gallons used, and gallons remaining. According to the system data, total fuel consumption was 19.6 gallons at an average rate of 12.7 gallons per hour. The cruise fuel flow was set between 12.2 and 12.6 gallons per hour.
Fuel System Characteristics
The aircraft's two main tanks each hold 20 gallons of fuel, for a total of 40 gallons, of which 34 gallons are usable. The interconnected auxiliary tanks add 20 gallons of fuel capacity. The fuel injection system returns approximately 10 gallons per hour of excess fuel. The return lines are routed through the selector valve to each main tank; however, for the auxiliary tanks, fuel is returned only to the left main tank. This means that when operating from the auxiliary tank, unused fuel is routed to the left main tank.
Fuel Consumption and Imbalance
The pilot burned 10.1 gallons from the left main tank before switching to the auxiliary tank. An additional 9.4 gallons were recorded as used from the auxiliary tank. However, the actual fuel withdrawn from the auxiliary tank was 19.4 gallons due to the fuel return system routing excess fuel to the left main tank. This extra fuel refilled the left main tank to capacity, leaving only 0.4 gallons in the auxiliary tanks. Fuel system guidance indicates that such a low quantity should only be used in level flight and never for takeoff or landing.