Method and tool for aided aircraft design using a criterion of operational availability

Computer-aided method for designing an aeronautic system forming all or part of an aircraft, characterized in that a plurality of different configurations of this system are extracted (210) from a database, and in that for each of these configurations,

• a maintenance time cost of said system is estimated for a given period of use by means of the following steps:
• computing (220) a first component equal to the mean flight time lost by the aircraft subsequent to a system failure during said period of use;
• computing (230) a second component equal to the mean unscheduled maintenance time subsequent to a system failure during said period of use;
• computing (240) a third component equal to the scheduled maintenance time for this system throughout said period of use;
• obtaining (250) said time cost as a weighted sum of the first, second and third components by means of first, second and third cost factors respectively;
• and
• in that the configuration of the system having the lowest maintenance time cost is selected (260).