A system for determining the performance of an aircraft for at least one flight phase, the system comprising: a first terminal comprising means for connecting to a first repository module comprising at least a first set of data files each comprising at least one aircraft performance lookup table containing performance values corresponding to an aircraft flight manual associated with a specific aircraft type and/or variant, a second repository module comprising a second set of executable scripts each associated with at least one data file from the first set of data files and comprising a series of steps for processing the at least one data file based on predefined rules corresponding to the aircraft flight manual, and a third repository module comprising a third set of configuration files each defining at least the configuration settings of the specific aircraft of the aircraft type and/or variant, the first terminal comprising a first user interface arranged for interacting with a first type of user, qualified for adapting aircraft settings, for providing and/or setting a set of input parameters comprising at least information relating to environmental conditions and information relating to the aircraft type and/or variant and aircraft settings, which input parameters are defined based on the selection of a configuration file from the third repository module; a second terminal comprising a second user interface arranged for interacting with a second type of user, qualified for adapting the configuration settings, the second terminal comprising means for connecting to at least the third repository module, for accessing the configuration settings defined in the configuration files, wherein the configuration files are in a predetermined format for the second type of user; a calling module arranged for being operatively coupled to the first and second repository modules and the first user interface, and arranged for selecting, based on the input parameters set via the first user interface and the configuration file selected, at least one executable script file for processing the associated data files; and a calculation engine arranged for determining the aircraft performance by processing the selected data files with the input parameters according to the associated at least one executable script file. a first terminal comprising means for connecting to a first repository module comprising at least a first set of data files each comprising at least one aircraft performance lookup table containing performance values corresponding to an aircraft flight manual associated with a specific aircraft type and/or variant, a second repository module comprising a second set of executable scripts each associated with at least one data file from the first set of data files and comprising a series of steps for processing the at least one data file based on predefined rules corresponding to the aircraft flight manual, and a third repository module comprising a third set of configuration files each defining at least the configuration settings of the specific aircraft of the aircraft type and/or variant, a first repository module comprising at least a first set of data files each comprising at least one aircraft performance lookup table containing performance values corresponding to an aircraft flight manual associated with a specific aircraft type and/or variant, a second repository module comprising a second set of executable scripts each associated with at least one data file from the first set of data files and comprising a series of steps for processing the at least one data file based on predefined rules corresponding to the aircraft flight manual, and a third repository module comprising a third set of configuration files each defining at least the configuration settings of the specific aircraft of the aircraft type and/or variant, the first terminal comprising a first user interface arranged for interacting with a first type of user, qualified for adapting aircraft settings, for providing and/or setting a set of input parameters comprising at least information relating to environmental conditions and information relating to the aircraft type and/or variant and aircraft settings, which input parameters are defined based on the selection of a configuration file from the third repository module; a second terminal comprising a second user interface arranged for interacting with a second type of user, qualified for adapting the configuration settings, the second terminal comprising means for connecting to at least the third repository module, for accessing the configuration settings defined in the configuration files, wherein the configuration files are in a predetermined format for the second type of user; a calling module arranged for being operatively coupled to the first and second repository modules and the first user interface, and arranged for selecting, based on the input parameters set via the first user interface and the configuration file selected, at least one executable script file for processing the associated data files; and a calculation engine arranged for determining the aircraft performance by processing the selected data files with the input parameters according to the associated at least one executable script file.