Fuel Policy, In-Flight Fuel Management and Contingency Planning
Fuel questions test the composition of the fuel plan and the in-flight decisions that follow from it: what each block of fuel is for, how contingency is calculated, what happens when the checks show a shortfall, and what the standard calls mean.
The fuel scheme (CAT.OP.MPA.150)
- Taxi fuel, trip fuel to the destination, contingency fuel (typically 5% of trip fuel, or a reduced figure only where approved methods and, where required, an en-route alternate are used), alternate fuel, final reserve, additional fuel and discretionary fuel.
- Final reserve is 30 minutes at 1500 ft above the destination aerodrome in ISA conditions for turbine aeroplanes, holding speed; 45 minutes for piston aeroplanes.
- Additional fuel is added when the circumstances need it: no usable destination alternate, isolated aerodrome, depressurisation or drift-down case, icing or forecast holding.
- The total is the sum of the blocks; the PIC may add discretionary fuel at any time.
In-flight management
- Fuel checks at regular intervals against the operational flight plan; a trend towards a shortfall requires a decision - reduce consumption, replan, or divert.
- MINIMUM FUEL: the aircraft is committed to land at a specific aerodrome and any change to the clearance may result in landing with less than final reserve.
- MAYDAY FUEL: the calculated usable fuel on landing is below final reserve. This is a distress call, not a request for priority alone.
Worked example
Taxi 200 kg, trip 4000 kg, contingency 5% = 200 kg, alternate 700 kg, final reserve 500 kg. Total fuel is 5600 kg. Two hours into the flight the crew check fuel: the aircraft would now land with 3500 kg at destination and 2800 kg at the alternate, against a planned 300 kg margin above final reserve - the projection shows final reserve would be breached. The crew must act immediately: replan, reduce level or speed, or divert, and declare MINIMUM FUEL once committed to a specific aerodrome.
Traps
- Calculating contingency on total fuel rather than trip fuel.
- Quoting final reserve at cruise level instead of 1500 ft above the destination.
- Treating taxi fuel as part of the contingency block.
- Confusing MINIMUM FUEL with MAYDAY FUEL.