Device for monitoring aircraft control information

1. A device for monitoring aircraft control information, the control information generated by at least two different flight management systems onboard an aircraft, comprising:

at least one computer external to said flight management systems and comprising a comparison unit that includes a first element for computing the differences, in twos, between control information originating from each of said flight management systems and a second element for comparing each of the differences with at least one predetermined threshold value; and

a warning system connected to said computer that generates a warning signal when at least one of said differences is greater than said threshold value, and that comprises at least one primary flight display generating a warning signal in the form of a change of bars relative to a flight director system, that are displayed on the primary flight display.

2. The device as claimed in claim 1 , wherein said warning system further comprises a warning unit to generate a warning signal to render passive a guidance function of an automatic pilot unit.

3. The device as claimed in claim 1 , wherein said warning system further comprises a display screen that displays a warning message illustrating said warning signal.

4. The device as claimed in claim 1 , wherein said warning system further comprises at least one warning means.

5. The device as claimed in claim 1 , wherein said primary flight display is formed to display, in addition to said bars relative to the flight director system corresponding to a side of the aircraft where said primary flight display is located, information relating to the flight director system corresponding to an opposite side.

6. The device as claimed in claim 1 , said device further comprises:

a first unit for generating at least two different current values of at least one flight parameter, originating from different sources; and

a second unit for verifying consistency between said current values, wherein

said warning system is formed to take account of processes applied by said second unit.

7. An aircraft guidance system, comprising:

an assembly of sources of information;

a flight management assembly connected to said assembly of sources of information and that includes at least two flight management systems configured for generating control information; and

an automatic pilot unit using data obtained from said control information to automatically guide the aircraft, which comprises a device for monitoring control information, as specified in claim 1 .

8. An aircraft comprising a guidance system as specified in claim 7 .