FAA Aircraft Dispatcher (ADX)Flight Planning and PerformanceHard
An aircraft is flying with a true airspeed of 240 knots. The wind is 25 knots striking the aircraft at a 60-degree angle relative to the course. What is the approximate wind correction angle required?
- A12 degrees
- B8 degrees
- C5 degrees
- D3 degrees
Show answer & explanationAnswer & explanation
Correct answer: C. 5 degrees
WCA = arcsin[(wind speed × sin(wind angle)) / TAS] = arcsin[(25 × sin60°)/240] = arcsin[(25 × 0.866)/240] = arcsin(21.65/240) = arcsin(0.0902) ≈ 5.2°, rounding to approximately 5 degrees.
Why the other options are wrong
- A. 12 degrees would require a much stronger crosswind component.
- B. 8 degrees overstates the correction needed.
- D. 3 degrees underestimates the crosswind effect.
Wind Correction Angle (WCA) Formula
WCA is calculated as the arcsine of the crosswind component divided by true airspeed: WCA = arcsin[(Wind Speed × sin(Wind Angle)) / TAS].
- Crosswind component = Wind Speed × sin(wind angle)
- WCA = arcsin(crosswind component / TAS)
- Heading = True Course ± WCA depending on wind direction
Memory trick: 'Sine the wind, divide by speed, arcsine gives the need.'