Except when a runway use program is in effect, use the calm wind runway when ___.

• A. less than 3 KT
• B. 3 KT or less
• C. less than 5 KT
• D. 5 KT or less

Answer: (C)

The idea being tested is knowing when wind is light enough to treat any runway as calm-wind eligible. In practice, a calm wind runway is chosen when the wind speed is below a small threshold so that wind effects don’t influence takeoff and landing decisions.

Here, the threshold is five knots; if the wind is less than five knots, you can select the calm wind runway unless a runway use program overrides. At exactly five knots, wind effects can become noticeable, so you wouldn’t classify it as calm wind for this rule.

That’s why the best choice is the one stating less than five knots. The other options are either too restrictive (requiring under three knots) or include five knots as calm (five knots or less), which isn’t correct per this criterion.