Patent ID: 8321072

Claim:
A method performed by a computer included in a flight management system for determining the quantity of fuel to be taken on board an aircraft and an optimization criterion capable of determining a speed profile, the method making it possible maintain a time requirement to within a determined criterion, said method comprising at least the following steps: a preliminary step, computing, via a method for determining the payload quantity of fuel, a gross weight of the aircraft in a first iteration, and the flight time of the aircraft resulting therefrom, as a function of an initial optimization criterion and a zero-fuel weight, a comparison step comparing the absolute value of the difference between the flight time determined in the previous iteration and the flight time required in order to observe the time requirement, with said determined criterion, passing to a subsequent iteration and initiating a first computation step when said difference is greater than the criterion, or initiating a last step otherwise, the first computation step, determining the optimization criterion in the current iteration as a function of the weight of the aircraft in the previous iteration via a method for determining an optimization criterion for maintaining a time requirement, then passing to the next iteration, a second computation step following the first computation step, determining, via a method for determining the payload quantity of fuel, the weight of the aircraft in the current iteration as a function of the optimization criterion in the previous iteration and of the weight of the aircraft in the previous iteration and the flight time resulting therefrom, the second computation step being followed by the comparison step, the last step determining the weight of fuel to be taken on board equal to the difference between the weight of the aircraft in the current iteration and the zero-fuel weight of the aircraft, and determining the optimization criterion equal to the optimization criterion in the previous iteration.