According to the pilot of the Glasair II, when the plane was in cruise flight near Spanish Fork, Utah, it experienced fuel flow problems. He activated the fuel system boost pump, putting it on the high-boost setting.
As he neared the destination airport, the engine quit. The airplane did not have enough altitude to glide to the runway, so he performed a forced landing in a field about 1,500 feet from the runway.
During the landing roll, the plane nosed onto its back hard enough to tear the wings off. The pilot was slightly injured.
A post-accident examination revealed that the electric boost pump would operate when the high-boost switch was selected. However, when the low-boost switch was selected, it would not operate due to a malfunctioning resistor.
Further testing revealed that when the electric boost pump was turned off and the engine-driven pump was trying to draw fuel without the use of the electric boost pump, the electric boost pump introduced air into the fuel system through a worn shaft on the pump. Investigators determined that air would likely hinder the engine-driven pump from producing enough suction and starve the engine of fuel.
The NTSB determined the probable cause of the accident was a loss of engine power due to fuel starvation, which likely resulted from air being introduced into the fuel system through the worn shaft of an electric fuel boost pump.
NTSB Identification: WPR13LA147
This March 2013 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.