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Fuel vent problem, Acro Sport 2

AaronM

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I was having some fun in my Acro Sport 2 last weekend and ended up losing an engine. A dead-stick landing quickly followed. I was able to get it down without damage to airplane, property, or myself.
Conditions of failure:
I was on my 12th or 13th aerobatic figure during a play session. I had done several maneuvers initiated from both upright and inverted. As I began the looping portion of a reverse half-cuban (5/8 loop following a roll to inverted on 45 upline), the engine quit. A quick check of the fuel pressure indicator showed absence of fuel pressure. Return to positive G did not regain fuel flow. A shot on the wobble-pump did regain pressure and momentarily restart the engine.


Post flight analysis:
I wasn't sure if I had something wrong with the flop-tube so I intended on using the dipstick to probe for tube freedom. As I released the pressure cap the tank sucked in a bunch of air. I was able to start and maintain fuel pressure at this point, so I taxied to the fuel pump.


At the pump:
I started off with 15 gallons. At the pump, the dipstick showed around 9.5 gallons. I intentionally overfilled the gas tank to see if fuel would run from the tank vent tube. As I got the fuel level high enough to do so, fuel began to exit the vent tube on the left gear-leg. There did not appear to be any contaminants or solidobjects that could have caused this discrepancy. To me this does not indicate a blocked tank vent.


Post pump engine runup:
So I had to try something. I sealed the pressure cap and started the engine. I ran the engine for about 15 minutes with the brakes held. For the record, I ran the engine well above half throttle for most of that time (at which engine temperatures started to rise and make me nervous). I exited the aircraft and quickly opened the pressure cap on the fuel tank. It exhibited normal behavior (did not gasp for air).


Any suggestions/comments/further troubleshooting would be GREATLY appreciated.


-Aaron McCartanEdited by: AaronM
 

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