FAA Commercial Pilot Airplane (CAX)Aerodynamics and PerformanceMedium
An airplane maintains a true airspeed of 120 knots in a coordinated 30° bank turn. Using the rate of turn formula, rate (°/sec) = (1,091 × tan(bank))/TAS, what is the approximate rate of turn?
- A6.5°/second
- B3.0°/second
- C5.25°/second
- D4.2°/second
Show answer & explanationAnswer & explanation
Correct answer: C. 5.25°/second
Rate = (1,091 × tan(30°))/120 = (1,091 × 0.577)/120 = 629.5/120 ≈ 5.25°/second. This is slightly faster than a standard-rate turn of 3°/second.
Why the other options are wrong
- A. This overestimates the rate for the given conditions.
- B. This is the standard-rate turn value, not the actual rate here.
- D. This underestimates the calculated rate of turn.
Rate of Turn Calculation
Rate of turn in degrees per second is found using rate = (1,091 × tan(bank))/TAS, showing that rate increases with steeper bank and decreases with higher airspeed.
- Standard rate turn = 3°/second (360° in 2 minutes)
- Higher TAS requires steeper bank for same rate
- Formula constant 1,091 derives from turn geometry
- Rate and radius are inversely related at constant bank
Memory trick: Faster you fly, slower you turn — steeper bank helps you churn!