Fuel Policy and Fuel Monitoring — Page 32, Lesson 39

I want to walk you through the fuel policy structure that governs every commercial flight you'll operate. This is the foundation of how we decide how much fuel to put on the aircraft before we even start the engines. Let's start with the big picture. An operator must ensure that every flight carries sufficient fuel for the planned operation, and reserves to cover any replanning necessary for in-flight contingencies. That word "contingency" means a chance occurrence or an unforeseen event — something you didn't plan for but that could happen. Now, the first type of reserve fuel I want to introduce is Contingency Fuel. This is carried specifically to compensate for three kinds of deviations. First, deviations of an individual aircraft from the expected fuel consumption data — your specific aeroplane might burn slightly more than the book says. Second, deviations from the forecast meteorological conditions — the wind might be stronger against you than forecast, or the temperature might be different. Third, deviations from the planned routing and/or cruising levels or altitudes — air traffic control might give you a different route or a lower level than you planned. Next we have Alternate Fuel. This one is straightforward: it's simply the fuel required to fly from a missed approach at the destination to the planned alternate aerodrome. When you calculate Alternate Fuel, you should take into account the probable routing and the expected wind component. But here's an important point: Alternate Fuel does not have its own allowance of contingency fuel. The contingency allowance is applied only to the trip fuel — the fuel for the main leg from departure to destination. Then we come to Final Reserve Fuel. Think about this scenario: you fly from departure to destination, you use your contingency fuel somewhere en route, then you have a missed approach at the destination and you have to fly to the alternate. If that happens, you will have no fuel left on arrival at the alternate. That's obviously unacceptable. So we have a minimum landing fuel, and you should normally never land with less than the Final Reserve Fuel. For jet and turboprop aircraft, Final Reserve Fuel consists of 30 minutes of fuel at 1500 feet above aerodrome level in ISA conditions. For piston engine aircraft, it's 45 minutes of fuel consumption at endurance speed. Now, Contingency Fuel, Alternate Fuel, and Final Reserve Fuel cover most cases. Provided that suitable diversions are available en route and near the destination, that's all you need for Reserve Fuel. But there are two cases where you may need Additional Fuel. The first case is called No Alternate, also known as the "Island Holding" situation. If there is no alternate available at some isolated aerodrome — think of a remote island airport — then you need to be able to cope with situations like the aircraft landing two minutes ahead of you bursting a tyre on the runway, or possibly a short duration tropical squall going through. You have nowhere else to go, so you need extra fuel to handle those delays. The second case is No En Route Alternate and Inability to Hold Height. If you are a long way from an alternate and you suffer some malfunction which requires you to reduce to a lower altitude — for example, an engine failure or a pressurization failure, or both — you may have to fly a long portion of the flight at a higher fuel consumption than planned. In that situation, you may need Additional Fuel. EU-OPS policy gives us a specific minimum for Additional Fuel in this second case. It states that the minimum Additional Fuel should be sufficient to permit: if an engine fails or the pressurization is lost at the most critical point, the aircraft to descend as necessary and proceed to an adequate alternate aerodrome and hold at 1500 feet for 15 minutes above the aerodrome elevation in ISA conditions. However, this additional fuel is not required if the adequate basic trip fuel, contingency fuel, alternate fuel, and final reserve fuel are already sufficient to complete that same profile. Let me show you a fuel graph that illustrates how all these components fit together. And here's a diagram showing what happens when you have insufficient fuel. Finally, here's a practical example routing from Oxford to Faro. So to summarise the reserve fuel structure: you have Contingency Fuel for unforeseen deviations, Alternate Fuel to get from the destination to your alternate, Final Reserve Fuel as your absolute minimum landing fuel, and then Additional Fuel for those special cases where no alternate exists or where you might lose height and burn more fuel than planned.