1. Field of the Invention
The present invention relates to a device for supervising the propulsion system of an aircraft, for example, of an airplane or a helicopter. In the context of the present invention, a propulsion system is understood to mean one or more propulsion sub-systems, each of these propulsion sub-systems including an engine with all of its movable elements and its monitoring systems, an air intake with its adaptor devices, and a nozzle possibly incorporating thrust reversal with the associated command, control and monitoring devices. In the case of a turbine engine, each of these propulsion sub-systems includes, moreover, devices for controlling and regulating the propeller, the rotor, or the "propfan" which this turbine engine drives.
2. Background Art
This propulsion system is extremely complex, thus making it very difficult for the crew monitoring it to observe and consolidate all the available information relating to it, Analysis of accidents or incidents arising in service shows that there is a significant number of cases in which the crew makes an appreciable error of assessment regarding the actual state of the propulsion system of the aircraft, as a consequence of poor interpretation of the information received.
It is known that, in order to pilot the propulsion system of an aircraft, the crew needs a certain amount of information, generally obtained by way of sensors intended to monitor certain important items of the propulsion system. The crew is thus aware of primary parameters, such as, for example, the EGT temperature and the speeds N1 and N2 of the rotors, and of secondary parameters, such as, for example, the level of the vibrations associated with the speeds N1 and N2, the temperature of the nacelles, the pressure or the fuel consumed. For example, in modern airplanes, this information is available in the EWD and SD ("Engine and Warning Display", "System Display") type images presented on a cathode-ray screen.
It is also known that warning devices are associated with some of these sensors, making it possible to advise the crew of an abnormal level of the values of the parameters monitored by these sensors. However, these warning devices exist for only a very limited number of sensors and they allow supervision of certain particular items only, and not overall supervision of the whole propulsion system.
No on-board device for overall supervision of the propulsion system of an aircraft exists.
Furthermore, the various parameters measured are generally redundant, both at the level of any one parameter, and also and especially through possible cross-checks between parameters, for example, between the rotation speeds of the various moving parts, the flow rate of fuel, certain characteristic pressures, the position of the movable elements, etc.
Cross-checks are, therefore, generally possible. However, they are not all that easy for the crew, especially under operational conditions, where the decision time is limited and where the crew is subject to numerous demands and constraints.