Final Reserve Fuel

What is Final Reserve Fuel?

Final reserve fuel is a mandatory component of an aircraft's fuel plan, ensuring a safety buffer for unforeseen circumstances. For turbine engine aircraft, it is defined as the amount of fuel required to hold for 30 minutes at 1500 feet above the aerodrome elevation under standard conditions. For aircraft with reciprocating engines, the requirement is 45 minutes at the same altitude.

How is Final Reserve Fuel Calculated?

The calculation is based on the expected mass of the aircraft upon arrival at the destination or alternate aerodrome. The holding speed and fuel flow at 1500 feet are used to determine the exact quantity. This value must be included in the total fuel loaded before departure and monitored throughout the flight.

Regulatory Requirements and In-Flight Management

Operators must ensure that, at any point during flight, the remaining usable fuel will not fall below the final reserve fuel upon landing. If in-flight fuel checks indicate that less than the required reserve will be available at landing, the commander must take corrective action—such as diverting to an alternate—to guarantee a safe landing with at least the final reserve fuel remaining.

Fuel Planning Structure

The total fuel for a flight is structured as follows:

• Taxi fuel
• Trip fuel
• Contingency fuel
• Alternate fuel (if applicable)
• Final reserve fuel
• Additional/extra fuel (for anticipated delays or at the commander's discretion)

Minimum Fuel Declaration and Emergency

If the commander determines that the aircraft will land with less than the final reserve fuel, an emergency must be declared. This ensures that ATC gives the flight priority handling, emphasizing the critical nature of final reserve fuel in operational safety.

Final Reserve Fuel in Fuel Jettisoning

If fuel jettisoning is required to reduce landing mass, the commander must ensure that the aircraft will still land with at least the final reserve fuel. Coordination with ATC is essential, and the operation must avoid populated areas and comply with minimum altitude requirements.