In-Flight Replanning and Fuel Management
This domain tests whether you can monitor the plan in flight, recognise a deteriorating fuel situation, and act before it becomes an emergency.
In-flight fuel management
- Record a fuel check at each waypoint and compare actual with planned; note the trend, not just the difference.
- Declare MINIMUM FUEL when the landing fuel is expected to be below final reserve; declare an emergency when the fuel is expected to be below that required to reach a safe landing.
- Consider diversion, PNR/ETP, reclearance and drift-down early rather than at the next waypoint.
- Manage fuel imbalance within limits and know when jettison is required or available.
Worked example
At waypoint B the planned fuel was 340 kg but actual is 315 kg, a 25 kg deficit. Remaining distance is 480 nm at 400 kt ground speed, which is 1.2 hours; at 240 kg/h that needs 288 kg. Add alternate fuel of 45 kg and final reserve of 120 kg, giving 453 kg required against 315 kg available. The plan cannot be completed with reserves intact, so divert or reclear now.
Traps
- Waiting until fuel is already below reserve before declaring MINIMUM FUEL.
- Ignoring APU, anti-ice, headwind or lower-than-planned levels.
- Using the planned burn rate when the actual rate is higher.
- Assuming both engines burn equally when one is running richer.