What is additional fuel intended for?

Additional fuel is specifically intended to handle emergencies, such as power unit failure or loss of pressurization. This type of fuel goes beyond the standard operational needs and reserves for normal flight routines and is critical for ensuring safety in unforeseen situations. In the event of an emergency, having this additional fuel allows pilots to have a contingency to safely manage their situation, such as diverting to an alternate airport or landing with a margin of safety.

In contrast, standard operational fuel covers the expected fuel consumption for the planned flight, while reserves are set aside for routine flying to ensure that the aircraft has enough fuel for a safe return or diversion if needed. Taxing fuel, while important, is typically accounted for in the total fuel calculation but does not serve the purpose of preparing for emergencies. This distinction is important for understanding how flight safety is prioritized with enough fuel to address potential complications during a flight.