A technician is explaining the benefit of an angle of attack (AOA) indicator to a pilot compared to relying solely on the airspeed indicator for stall avoidance. Which statement correctly describes why the AOA indicator provides a more reliable stall warning margin?
- AAOA readings are only accurate in straight-and-level, unaccelerated flight
- BAOA is derived from local airflow angle at the sensor and remains valid regardless of aircraft weight, altitude, or bank angle
- CAOA indicators replace the need for pitot-static instruments entirely
- DAOA indication is directly affected by aircraft weight and bank angle, giving a more conservative margin
Show answer & explanationAnswer & explanation
Correct answer: B. AOA is derived from local airflow angle at the sensor and remains valid regardless of aircraft weight, altitude, or bank angle
An AOA indicator senses the actual angle between the wing chord line and the relative wind using a vane or differential pressure probe, and transmits this electrically to a cockpit display. Unlike stall speed (which changes with weight, bank angle, and load factor), the critical angle of attack at which a wing stalls is constant, so the AOA indication remains an accurate stall margin in any flight condition.
Why the other options are wrong
- A. AOA indicators are specifically useful during maneuvering and accelerated flight, not just level flight.
- C. AOA indicators supplement, not replace, pitot-static instruments like the airspeed indicator.
- D. AOA indication is independent of weight and bank angle, which is precisely its advantage.
Angle of Attack (AOA) Indicator
An electrical instrument that senses local airflow angle via a vane or differential pressure probe and displays angle of attack, providing a stall margin independent of weight, altitude, or bank angle.
- Critical AOA at stall is constant regardless of weight or bank angle
- Sensor may be a vane-type or differential pressure probe
- Signal is transmitted electrically to a cockpit indicator or display
Memory trick: Angle, not airspeed, tells the wing when it's about to quit.