Aviation safety investigations & reports

Total power loss - Gemini Thruster TST-E, Beebyn Station WA, 24 November 1989

Investigation number:
Status: Completed
Investigation completed


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The pilot had planned to carry out a bore-hole inspection on his property. During the start-up sequence the pilot noted that more choke than normal was required, however, after start-up the engine ran smoothly. Approximately 30 minutes after take off the pilot observed air bubbles flowing through the transparent fuel line. The engine began to run roughly and stopped. The pilot commenced forced landing procedures and attempted to restart the engine by hand priming the fuel system using the rubber manual priming bulb. The bulb, once compressed, did not return to its original size. The pilot was forced to carry out a forced landing on unsuitable terrain and the aircraft was damaged. The engine fuel pump non-return valve was found jammed in the open position by black rubber particles. These particles had come from the inside wall of the manual priming bulb. An open non-return valve will cause a loss of pressure within the fuel system and engine failure. The fuel tank is mounted well below the engine. Once the particles were removed from the fuel system the engine ran normally. The aircraft's history indicated that it had been left standing in hot and dry conditions for some time allowing the rubber priming bulb to dry out. Manual operation of the dry bulb probably caused internal cracking and allowed rubber particles to contaminate the fuel system.

Download Final Report
[Download  PDF: 23KB]
General details
Date: 24 November 1989   Investigation status: Completed  
Time: 1630    
Location: Beebyn Station    
State: Western Australia    
Release date: 26 April 1990   Occurrence category: Accident  
Report status: Final   Highest injury level: None  

Aircraft details

Aircraft details
Aircraft manufacturer Thruster Aircraft (Australia) Pty Ltd  
Aircraft model Gemini Thruster  
Type of operation Unknown  
Damage to aircraft Substantial  
Departure point Beebyn Station, WA  
Departure time 1600  
Destination Beebyn Station, WA  
Last update 21 March 2016