FAA Flight Instructor Airplane (FIA)Performance, Weight and BalanceHard
An airplane's calibrated stall speed in level flight is 60 knots. During a steep, coordinated 60° bank turn, the load factor is 2 G. What is the approximate stall speed in this turn?
- A85 knots
- B77 knots
- C60 knots
- D69 knots
Show answer & explanationAnswer & explanation
Correct answer: A. 85 knots
Stall speed increases with the square root of the load factor: Vs(turn) = Vs(level) × √n = 60 × √2 = 60 × 1.414 ≈ 85 knots.
Why the other options are wrong
- B. This corresponds to a load factor of about 1.65, not 2.
- C. This ignores the load factor entirely.
- D. This corresponds to a load factor of about 1.33, not 2.
Load Factor and Stall Speed
In a coordinated turn, load factor increases with bank angle, and stall speed increases proportionally to the square root of the load factor.
- 60° bank = 2 G load factor
- Vs(turn) = Vs(level) × √n
- Steeper banks dramatically raise stall speed
Memory trick: Square Root Shoots stall speed up in steep banks