FAA Airline Transport Pilot (ATM)Aircraft Performance and Weight and BalanceEasy
A pilot is landing on Runway 21 (heading 210°M). The current wind is reported as 240° at 30 knots. What is the crosswind component the pilot must account for?
- A20 knots
- B15 knots
- C26 knots
- D30 knots
Show answer & explanationAnswer & explanation
Correct answer: B. 15 knots
The wind angle relative to the runway is 240° − 210° = 30°. Crosswind component = wind speed × sin(angle) = 30 kt × sin(30°) = 30 × 0.5 = 15 knots. The headwind component would be 30 × cos(30°) ≈ 26 knots, which is a separate value often confused with the crosswind component.
Why the other options are wrong
- A. Not a value produced by the sine/cosine relationship for this angle.
- C. This is the headwind component (30 × cos30°), not the crosswind.
- D. This is the total wind speed, not the resolved crosswind component.
Crosswind Component
The portion of reported wind acting perpendicular to the runway, found using wind speed multiplied by the sine of the angle between wind direction and runway heading.
- Crosswind = wind speed × sin(wind angle off runway)
- Headwind = wind speed × cos(wind angle off runway)
- A 90° crosswind angle produces the maximum crosswind component
Memory trick: SOH-CAH-TOA: Sine gives the Side (crosswind), Cosine gives the Coming-at-you (headwind).