Flight control system for determining a fault based on error between a measured and an estimated angle of attack

A flight control system for an aircraft including a plurality of displays, the flight control system comprising:

• one or more processors;
• a plurality of angle of attack sensors in communication with the one or more processors, wherein the plurality of angle of attack sensors are configured to measure a raw angle of attack;
• and
• a plurality of pitot tubes in communication with the one or more processors, wherein the plurality of pitot tubes measure a total pressure;
• a memory coupled to the one or more processors, the memory storing data comprising a database and program code that, when executed by the one or more processors, causes the flight control system to:
• receive a signal indicating the total pressure;
• determine a measured angle of attack that is based on the raw angle of attack and a true airspeed of the aircraft;
• receive as input an estimated angle of attack that is based on the total pressure;
• compare the measured angle of attack with estimated angle of attack to determine an error;
• in response to determining that the error between the measured angle of attack and the estimated angle of attack exceeds a threshold value, determine the presence of a fault with a majority of the plurality of angle of attack sensors and provide the estimated angle of attack to the plurality of displays;
• determine a measured dynamic pressure based on the total pressure and a static pressure;
• determine an estimated dynamic pressure based on data collected from a plurality of control surfaces, inertial, and angle of attack sensors;
• compare the measured dynamic pressure and the estimated dynamic pressure with one another to determine a difference;
• in response to determining the difference between the measured dynamic pressure and the estimated dynamic pressure exceeds another threshold value for a threshold amount of time, determine the presence of a common mode fault of the measured dynamic pressure;
• and
• in response to determining the presence of the common mode fault of the measured dynamic pressure, determine the measured angle of attack based on the estimated dynamic pressure.

A method for determining a fault with an angle of attack value for an aircraft, the method comprising:

• receiving a signal indicating a total pressure, wherein the total pressure is measured by a plurality of pitot tubes;
• determining, by a computer, a measured angle of attack that is based on a raw angle of attack and a true airspeed of the aircraft;
• determining, by the computer, an estimated angle of attack that is determined based on the total pressure;
• comparing, by the computer, the measured angle of attack with the estimated angle of attack to determine an error;
• in response to determining the error between the measured angle of attack and the estimated angle of attack exceeds a threshold value, determining the presence of the fault with the angle of attack value, wherein the estimated angle of attack is provided to a plurality of displays;
• determining a measured dynamic pressure based on the total pressure and a static pressure;
• determining an estimated dynamic pressure based on data collected from a plurality of control surfaces, inertial, and angle of attack sensors;
• comparing the measured dynamic pressure and the estimated dynamic pressure with one another to determine a difference;
• in response to determining the difference between the measured dynamic pressure and the estimated dynamic pressure exceeds another threshold value for a threshold amount of time, determining the presence of a common mode fault of the measured dynamic pressure;
• and
• in response to determining the presence of the common mode fault of the measured dynamic pressure, determining the measured angle of attack based on the estimated dynamic pressure.