Plane: RV9A IO320 stock per plans, Stock vans boost pump installed per Vans instructions. Number of hours on plane 102. No issues with fuel flow to engine during this incident or at any other time. Stock vent line and sniffle drain
A few weeks ago I had my tanks top off buy the fuel truck before flight. Unfortunately he over filled them to the point where when cap was installed fuel flood the wing, No big deal I cleaned it off.
Did run up, turned boost pump on for take off. After takeoff the tower had me do a series of 3 sharp 45 degree plus turns 1 right and 2 left for traffic avoidance. My fuel pressure with or without the boost pump runs about 37-40psi. I have the squawk limit to 40 so, I did here one squawk that indicated it got to 40 psi for a short moment and then dropped back down to 37 psi. I turned the boost pump off and I flew for 10 min or so to a near by airport and did 1 touch and go.
On departing this airport I look down and saw that I only 9 gallons in my right tank which was the active tank. I thought stuck fuel gauge lever. Rocked the wings and saw the fuel level bounce up and down. Ran for a bit on that tank and did not see further rapid fuel loss on the gauge. I switched tanks and proceeded on to my destination. On arriving I sticked the tank and I had indeed lost a bunch of fuel. Further operation of the plane has showed no further fuel loss.
So: what happened? Did the fuel siphon out the vent line on the steep turns after takeoff, because fuel was compressed into the top of the vent lines lines due to the overfill and start a siphon on the steep turns, this really seems like a physical possibility? Or does a IO320 fuel pump dump consider 40PSI an over pressure and dump the fuel?
A few weeks ago I had my tanks top off buy the fuel truck before flight. Unfortunately he over filled them to the point where when cap was installed fuel flood the wing, No big deal I cleaned it off.
Did run up, turned boost pump on for take off. After takeoff the tower had me do a series of 3 sharp 45 degree plus turns 1 right and 2 left for traffic avoidance. My fuel pressure with or without the boost pump runs about 37-40psi. I have the squawk limit to 40 so, I did here one squawk that indicated it got to 40 psi for a short moment and then dropped back down to 37 psi. I turned the boost pump off and I flew for 10 min or so to a near by airport and did 1 touch and go.
On departing this airport I look down and saw that I only 9 gallons in my right tank which was the active tank. I thought stuck fuel gauge lever. Rocked the wings and saw the fuel level bounce up and down. Ran for a bit on that tank and did not see further rapid fuel loss on the gauge. I switched tanks and proceeded on to my destination. On arriving I sticked the tank and I had indeed lost a bunch of fuel. Further operation of the plane has showed no further fuel loss.
So: what happened? Did the fuel siphon out the vent line on the steep turns after takeoff, because fuel was compressed into the top of the vent lines lines due to the overfill and start a siphon on the steep turns, this really seems like a physical possibility? Or does a IO320 fuel pump dump consider 40PSI an over pressure and dump the fuel?