A method for processing a request message received in an aircraft, from air control, via a data transmission system, includes the identification of a type of request contained in the received message and the extraction of parameters associated with the type of request identified. The method further includes steps of determining flight characteristics to be calculated according to the type of request identified and the said associated parameters; selecting at least one calculation module, from among a predetermined set of calculation modules, according to the determined flight characteristics to be calculated; calculating flight characteristics with at least one selected calculation module, and obtaining calculation results; and creating a draft for response to the said request from the calculation results obtained.