The maximum possible discretionary fuel that can be uplifted is determined by the lowest of the following discretionary fuel quantities:

Brake Release Mass - Actual Take-off Mass:

Brake Release Mass− (Dry Operating Mass + Traffic Load + Minimum Block Fuel − Taxi Fuel) = 68 000 kg − (42 500 kg + 12 531 kg + 11 249 kg − 240 kg) = 68 000 kg − 66 040 kg = 1960 kg

Maximum Landing Mass - Actual Landing Mass:

Maximum Landing Mass − (Dry Operating Mass + Traffic Load + Minimum Block Fuel − Taxi Fuel − Trip Fuel) = 66 360 kg − (42 500 kg + 12 531 kg + 11 249 kg − 240 kg − 7931 kg) = 66 360 kg − 58 109 kg = 8251 kg

Fuel Tank Capacity - Minimum Block Fuel:

Fuel Tank Capacity − Minimum Block Fuel = 20 000 kg − 11 249 kg = 8751 kg

From these calculations, we conclude that the maximum possible discretionary fuel to be uplifted for a direct climb to the optimum altitude of 37 000 ft is 1960 kg.

Note: The Maximum Zero Fuel Mass (MZFM) does not need to be considered in the calculation of the discretionary fuel.