What is the operating principle of the sensing device used in an autopilot system?

What is the operating principle of the sensing device used in an autopilot system?

• A. Relative motion between a gyro and its supporting system
• B. Rotational speed of the aircraft on the ground
• C. Electric current in the gyro windings
• D. Change in magnetic field due to magnetized core

Answer: (A)

The key idea is how a gyroscope provides attitude or rate information for an autopilot. A gyro’s rotor tends to keep pointing in the same direction (rigidity in space). When the aircraft’s frame turns, the gyro’s rotor resists that change and the gimbal system experiences a relative motion between the gyro and the airplane. This relative motion is converted into an electrical signal that represents the angular rate of turn about each axis. The autopilot uses those signals to keep the aircraft stable by commanding the control surfaces. The other options don’t match how autopilots sense motion. Rotational speed on the ground isn’t what an in-flight autopilot senses for stability. Electric current in the gyro windings describes how power is supplied, not the fundamental sensing action. A change in magnetic field due to a magnetized core points to magnetic sensing like flux valves or compasses, not the gyroscopic method used for attitude and rate sensing in most autopilots.

The key idea is how a gyroscope provides attitude or rate information for an autopilot. A gyro’s rotor tends to keep pointing in the same direction (rigidity in space). When the aircraft’s frame turns, the gyro’s rotor resists that change and the gimbal system experiences a relative motion between the gyro and the airplane. This relative motion is converted into an electrical signal that represents the angular rate of turn about each axis. The autopilot uses those signals to keep the aircraft stable by commanding the control surfaces.

The other options don’t match how autopilots sense motion. Rotational speed on the ground isn’t what an in-flight autopilot senses for stability. Electric current in the gyro windings describes how power is supplied, not the fundamental sensing action. A change in magnetic field due to a magnetized core points to magnetic sensing like flux valves or compasses, not the gyroscopic method used for attitude and rate sensing in most autopilots.