Usually, the performance module comprises a performance computation unit, at least one performance database and at least one data input unit. Variables resulting from performance computations are generated by the computation unit based on data coming from the performance database and of data entered using the data input unit.
The computation unit carries out performance computations which are required in order to accomplish various functions, for example in order to determine fuel consumption and/or flight time along a flight plan predictions.
The performance database which is installed in the flight management system comprises one or more performance files. Each performance file contains a set of data relative to the engine, the aerodynamics or to other data related to performance, such as the characteristic speeds of the aircraft, and this being for a given type of aircraft.
In the context of the present disclosure, type of aircraft is understood to be a particular combination of a given type of aerodynamic structure and a given type of engine.
In general, the performance database is produced under the responsibility of the original manufacturer of the aircraft. This performance database is installed within the FMS system and, as a component of the FMS system, must meet qualification standards imposed by the air authorities.
The processes associated with the performance variables therefore generate data representative of a type of aircraft, and not of an individual aircraft. Now, it so happens that each aircraft individually has specific characteristics, for example because of the ageing of the components constituting that aircraft and of the renewal of a portion of those components throughout the service life of that aircraft.
The performance file or files which are therefore representative of a given type of aircraft do not make it possible to represent accurately the specific characteristics of the individual performances of the aircraft (of that given type) in question.
One solution compatible with this prior art could be to produce performance databases with a plurality of performance files for individual aircraft and to make provision for frequent updates of the databases in order to take account of the ageing of the aircraft, its maintenance, etc. However, such a solution would not be satisfactory or even feasible for various reasons, and notably:
the process for generating new performance databases is generally long and costly;
the configuration management required for distributing that many performance databases would be too inconvenient for the manufacturers or the airline companies; and
the adjustment of the performance database for an individual aircraft necessitates a very large number of flight data recordings for that particular aircraft, which are not available from the manufacturer of the aircraft before delivery of the aircraft to the customer.
Consequently, it cannot be envisioned to provide such a solution consisting of or comprising generating new performance database files in order to adapt the data to the effective individual state of an aircraft.
The usual situation is not therefore completely satisfactory, because the performance model is not optimized for a given specific aircraft (of that type of aircraft).