Holding Fuel
Holding fuel refers to the amount of fuel an aircraft needs to fly for the anticipated time spent holding, calculated at the aircraft's holding fuel consumption rate, and is a component of the total fuel required for a flight.
Purpose
Holding fuel ensures an aircraft has enough fuel to remain in a holding pattern (a procedure where aircraft wait at a specific point in the airspace) for the expected duration.
Calculation
The amount of holding fuel is determined by:
- The anticipated holding time.
- The aircraft's holding fuel consumption rate (how much fuel the aircraft burns while holding).
- The anticipated meteorological conditions (weather) or ISA (International Standard Atmosphere).
Importance
Holding fuel is a crucial part of flight planning, as it ensures that the aircraft has enough fuel to complete the flight and any necessary holding procedures.
Variations
Operators may specify conservative criteria to be used in calculating holding fuel consumption rates. A commonly applied methodology is to round up the holding fuel consumption rate to a readily recallable fuel consumption rate value that is valid in all but the most unlikely holding scenarios.
Other Fuel Types
Besides holding fuel, other types of fuel are considered in flight planning, including:
- Contingency fuel: Fuel to cover unforeseen circumstances like weather deviations, route changes, or air traffic delays.
- Alternate fuel: Fuel required to fly to and land at a designated alternate airport if the primary destination airport becomes unusable.
- Final reserve fuel: The minimum fuel required to fly for a specific time (e.g., 45 minutes) at a holding speed at the destination or alternate airport.
