Incident
During a touch-and-go takeoff, a student pilot switched the fuel selector to the opposite tank, and the engine subsequently quit. The certified flight instructor (CFI) took control of the aircraft and performed an off-airport landing in a vineyard located at the departure end of the runway.
Inspection
During the on-scene inspection of the airframe, a functional check of the fuel system was conducted. With the master switch engaged and the electric boost pump in the ON position, the pump was observed to be operating; however, no fuel pressure was noted, and no fuel was found in the gascolator.
An inspection of the fuel selector valve was then performed. After removal, the valve was found positioned between the left and right port openings, and the fuel valve control rod could not be turned manually. The plastic fuel selector handle was removed and found to be cracked. The brass insert, which is housed in the fuel selector handle and attaches to the fuel valve control rod, would not engage completely inside the plastic handle. There were no previous signs of cracks in the plastic fuel selector handle.