The present invention relates to back-up instruments for aiding the piloting of an aircraft, which instruments are intended to provide, with high security of operation, indications relating to the pressure altitude, the conventional speed and the attitude (angles of roll and of pitch) of the aircraft, this being for the purpose of serving both as reference for the control of the proper operation of the main systems of on-board and back-up instruments in the event of a fault with the main system or systems of on-board instruments. It relates more particularly to combined back-up instruments including an electronic portion endowing them with a degree of calculational power. It consists in providing, in these combined back-up instruments which operate exclusively on the basis of measurements of total pressure and of static pressure and inertial measurements originating from their own sensors, a correction of the static pressure measurement error due to the aerodynamic angle of incidence of the aircraft as computed solely on the basis of the information already at the disposal of these back-up instruments, doing so in order to improve the accuracy of the indication of pressure altitude without thereby increasing the cost or reducing the safety of operation of the combined back-up instruments.
The device (1) comprises a set (3) of information sources, an information processing unit (4), a display means (6) comprising a display screen (8), and a configuration means (9) allowing an operator to configure said device (1), according to one of the three configuration states, a first configuration state, for which the display means (6) presents aircraft piloting information, a second configuration state, for which the display means (6) presents aircraft navigation information, and a third configuration state, for which the display means (6) presents both piloting information and navigation information.
