FAA Instrument Rating Airplane (IRA)Flight Instruments and SystemsEasy
A flight instructor explains that a gyroscope resists any force that attempts to change the plane in which the rotor is spinning, causing it to maintain a fixed orientation in space unless acted upon by an outside force. Which gyroscopic property is being described?
- APrecession
- BReal drift
- CRigidity in space
- DGimbal error
Show answer & explanationAnswer & explanation
Correct answer: C. Rigidity in space
Rigidity in space is the property that allows a spinning gyroscope to maintain its orientation regardless of the earth's rotation or aircraft movement, which is the basic principle used in attitude and heading indicators.
Why the other options are wrong
- A. Precession is the deflection of the gyro 90° ahead in the direction of rotation when a force is applied, not the tendency to stay fixed.
- B. Real drift refers to actual gyro movement over time, not the fundamental property described.
- D. Gimbal error occurs from mechanical limits of the gimbal mounts, a different concept.
Rigidity in Space
The gyroscopic property causing a spinning rotor to maintain its plane of rotation fixed in space unless acted upon by an external force.
- Basis for attitude and heading indicators
- Greater rotor mass and speed increase rigidity
- Distinct from precession, which is the gyro's response to applied force
Memory trick: Rigid gyros 'refuse to move' like a stubborn spinning top.