Thursday, 22 January 2015
MANAGING FUEL IN FLIGHT
MEMORY JOGGER #3
MANAGING FUEL IN FLIGHT
Most low-wing single-engine aircraft cannot feed from both fuel tanks at the same time and so have LEFT, RIGHT and OFF fuel selector positions. To maintain lateral balance, try to keep the tanks as equal as reasonably possible. For example, after take-off fly for half an hour on one tank, and then an hour on the other, switching hourly thereafter. This should keep you from having more than a half-hour’s fuel imbalance at any given time.
As the tanks are sited lower than the engine, fuel must be pumped. Fuel Pump use can vary from one aircraft to another. Some designs require the boost pump to be on for landing and take-off; in others the boost pump is to be used only at high altitude or when the mechanical pump fails. Pilots must be familiar with fuel pump operation for each aircraft they fly.
Safety tip: When fuel tanks are not full, ‘over-zealous’ on-ground manoeuvring could move fuel in the tank away from the outflow ports, so avoid sharply-accelerating turns when given permission to enter the runway for take-off with immediate clearance.
In-Flight, deviations for weather, stronger headwinds, or the discovery of low fuel condition may require you to maximize fuel economy. To conserve fuel:
• Slow down: You’ll burn less fuel if you cruise at a lower power setting.
• Fly with the wind: If you have a choice of equidistant fuel stops, pick the one that’s downwind. You may have to backtrack but you’ll burn less fuel and get there faster.
• Lean for best economy: Consult the POH for best economy/long endurance power settings and leaning procedures
Warning: Fuel consumption figures given in the POH are based on a properly leaned engine operating at a specific power setting. One way to get to know your actual fuel consumption is to estimate how much fuel your airplane will take at each fuel stop. Comparing this with what actually goes into the tanks is a good way to develop “fuel sense.”
Safety tip: In flight, recalculate range and endurance hourly. Compare your calculation with distance to destination, to confirm you have adequate fuel reserve and to allow timely needed adjustment to your flight plan. Your GPS provides accurate information about ground speed and time en route, which are essential parameters for determining adequate fuel reserves.
Accident Report: Before departing cross-country, the pilot of a Piper Cherokee Six requested that his two main tanks and two auxiliary tanks be “topped”, but the Re-fueller subsequently stated that only the mains were filled. En route, the pilot became aware of a low fuel condition. The engine lost power about five miles out and an off-airport landing was made. A passenger stated that the pilot had considered landing for fuel but elected to continue to destination. The pilot and two passengers died and three remaining passengers were seriously injured, indicating the importance of checking actual fuel uplift against requirement before departing.