Air data failure management in a full-authority fly-by-wire control system

The aim of the air data system, in a full-authority fly-by-wire control system, is the determination of flight parameters, such as pressure altitude, Mach number, angles of attack and sideslip, from measurements of local pressures and of local flow angles on wings or fuselage, provided by a proper set of sensors. The architecture of the air data system is redundant in order to achieve the adequate level of reliability and safety. In this paper a possible methodology for the management of the redundancies of the air data system is described, which has been developed with reference to the air data system of the new jet trainer Aermacchi M-346. The developed algorithms identify the possible failures and provide an adequate system reconfiguration by comparing different estimates of the flight parameters. In addition, such algorithms are able to manage temporary situations where one or more sensors do not provide reliable measurements since they are in the wake of the fuselage.