We all know the all-important FREDAS check that is done every 15-20 minutes in the cruise. The check is started with the most crucial check, FUEL. The FoxBat does not have a “BOTH” selector for the fuel flow to the engine like we would see in the Cessna 172. This means that fuel is drawn from either the left tank or the right tank and this depends on the selection made by the pilot. It is very important to balance the fuel levels between the two tanks. This is not only for safety to ensure that you have enough fuel, but also to ensure balanced flight. With a empty left or right wing, you may create an unnecessary x-wind component that does not even exist! It is also important to remember that not every drop of fuel in the wings are usable. So be safe and balance the tanks by drawing the fuel evenly from the tanks during your flight.
Make sure the fuel is filled evenly between the two tanks at the fuel bay. Here is the procedure to ensure the balancing of fuel levels for your flight.
Fuel Management during TAXI: After your pre-flight is completed, start the aircraft with the RH tank. When you have completed your after start checks, change to the LH tank for the taxi to the holding point. We do the engine run-up and take-off on the right hand tank. The landings are also done with the RH tank selected. The reason we change tanks during ground movements is to ensure that we have fuel flow from both sides before commencing with the take-off and also to balance fuel levels in the tanks. Always ensure that you have fuel flow during the switching of fuel tanks. When switching from RH to the LH tank, ensure that Left is ON before switching OFF the Right tank. Make sure the ‘new’ tank is ON before switching OFF the ‘old’ one. This ensures constant fuel flow. The FoxBat is fitted with a very small reservoir for preventing the sudden loss of fuel flow, but this is only for a very short duration and pilots should prevent the scenario of a fuel cut at all costs.
Fuel Management during the CRUISE: In the cruise we do the safety check, FREDAS. This happens every 15-20 minutes and is a good time interval for balancing the fuel. Have a look at the image below, the fuel gauges indicate an imbalance, something that is to be avoided. Our two FoxBat planes uses an average of 17-20 liters of fuel per hour, so you’ll draw 5-7 liters of fuel from a tank in a 15-20 minute duration. Here is the procedure to follow in straight & level flight.
1 – Field in sight
2 – Aux Fuel Pump ON, pressure within limits
3 – Switch Tanks, Ensure constant Fuel Flow
4 – Aux Fuel Pump OFF, pressure within limits
5 – Field still in sight
6 – Confirm Fuel Pressure within limits
The reason we choose a field before and after the procedure is to have a safe place to land in the event of an inadvertent fuel cut and the situation can not be solved, causing an emergency situation and landing. When you choose a field, look for a field that looks firm (light in color), the overshoot and undershoot is clear of obstacles, the surface is clear of obstacles. In a perfect scenario you’d like to land away from the sun, into the wind and uphill. Have you ever heard the term “staying ahead of the aircraft”? This is what is is all about. You are prepared for when something unexpected is about to happen and the startle effect may not be as pronounced as it might have been.
Have a look at the video of the procedure below. One of our FoxBat PPL students is demonstrating the procedure perfectly.
Thank you for your time.
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