Incident
On 1 June 2000 at 2014 UTC, a CASA 1.131-E3B (registration G-BXBD) experienced an engine failure while on a private air test for permit renewal. The pilot and an engineer were on board; neither was injured.
Sequence
The pilot applied moderate negative g, causing the engine to cut. Attempts to restart by diving and advancing the throttle were unsuccessful. At about 1,000 ft agl and 120 kt, the pilot declared a Mayday and selected a field. Power cables at the upwind end prompted a landing further down the field. The aircraft cleared the first wires but encountered a second set at 100 ft, hidden by trees. Unable to climb over, the pilot attempted to fly under, striking trees. The aircraft pitched nose-first and came to rest; both occupants evacuated without injury.
Fuel System Analysis
The CASA 1.131-E has a fuel tank with two outlets selectable by a three-position valve: CLOSED, OPEN, and RESERVE AND PRIME. The OPEN position uses a flop tube for negative g conditions. The pilot admitted to forgetting to select OPEN after starting; the selection remained on RESERVE AND PRIME. Consequently, negative g interrupted fuel flow.
Probable Cause
The pilot's failure to select the OPEN fuel position, resulting in engine fuel starvation under negative g.