What is the maximum crosswind on a contaminated runway when the contaminant measure is greater than 150?

• A. 10 kts
• B. 12 kts
• C. 20 kts
• D. 15 kts

Answer: (D)

When a runway is contaminated, directional control and braking are less effective, so the safe crosswind limit is reduced. The contaminant measure quantifies how severe the contamination is; as it rises, the surface grip and braking degrade, requiring tighter limits to keep the aircraft controllable during landing and rollout. With a contaminant measure greater than 150, the established safety limit for crosswind is 15 knots. This value provides a margin that accounts for the degraded surface, helping prevent loss of control in a crosswind on a slippery runway. Smaller limits (like 10 or 12 knots) would be unnecessarily restrictive at this contamination level, and a higher limit (like 20 knots) would not be considered safe given the surface conditions.