Method for dynamic control of the performance of an aircraft computed on the basis of a real aircraft data input file and a computation data input file, using a computerised flight manual running on a terminal equipped with a commercial operating system, which comprises the following steps: a step of computing the performance of the aircraft on the basis of said real aircraft data input file, and said computation data input file, and obtaining at least one first result file, a step of computing reference performances on the basis of a reference data input file, and obtaining at least one third result file, which step is performed in parallel with the previous step, a first step of comparing the at least one third result file with the at least one reference result file, so as to detect any malfunction of the operating system with the application of numerical margins tolerated on the results of the result files, a step of deleting the at least one first result file and sending an error message to the user if the result of this first comparison step is negative.