Angle of Attack

Question 1

Vane sensor

Answer 1

• Functions like a wind vane: pivoted well forward of its centre of pressure.
• Vane angle measured to infer AoA

Question 2

Null-seeking rotor

Answer 2

• Pressure in two ports is compared
• Pressure difference commands servo-motor to realign rotor until port pressures are equal

Question 3

Anti-icing protection

Answer 3

Electrical heating is used to protect AoA sensors from icing

Question 4

Types of AoA display

Answer 4

• Gauge showing the proportion of maximum AoA or a numerical value
• Light display showing green, amber or red according to margin before stall

Question 5

Systems using AoA data

Answer 5

• ADC
• Stall warning system
• Flight envelope protection systems

Question 6

Impact of incorrect AoA data

Answer 6

• degradation of flight control systems
• malfunction of stall protection systems
• reversion to degraded control modes or laws
• incorrect or unnecessary function of flight envelope protection systems
• loss of situational awareness

Question 7

Effect of incorrect display of AoA to pilots

Answer 7

• Is not likely to cause major issues because it is a secondary indication
• Should be easy to identify through awareness of pitch, power, and airspeed