An attitude computer (Engl. Flight control system , FLCS ) is a calculator for quick control and correction of movements of an aircraft .
The flight attitude is determined as the angle of the three axes of the aircraft to the respective reference angle:
- Angle (engl. Pitch angle ): the angle between the vertical axis of the aircraft and the solder center of the earth.
- Roll angle (engl. Bank angle ): the angle between the horizontal and the plane transverse axis.
- Yaw angle (engl. Yaw angle ): the angle between the actual direction of movement through the air and the aircraft longitudinal axis. This angle is usually not controlled by the FLC because it results from the aircraft geometry and aerodynamics.
A flight attitude computer works as a controller that regulates one of the first two angles by keeping the angle at the value that the pilot once specified. Two computers or two channels of one computer are required for two axes.
The FLC is expressly not an autopilot because it cannot react to malfunctions. Example: With a given engine power, a very specific angle of attack occurs at constant speed. The FLC is now instructed to maintain this angle and the pilot no longer intervenes. At first, everything stays as the pilot intended. However, the engines consume fuel, which means that the aircraft becomes lighter and therefore faster. The aerodynamics of a conventional airplane mean that the airplane wants to take its nose up. However, the FLC does not allow this and counteracts this with the elevator. The attitude is now maintained, but due to the lower downforce and thus lower resistance, the speed continues to increase and the aircraft wants to take up its nose again. The FLC steers against it again and since only the flight attitude is regulated, the aircraft can reach a critical speed up to and including the destruction of the structure.