Besides exemption 3585, when is a second alternate needed?

• A. Marginal weather at destination and alternate at minimums.
• B. Always.
• C. Only when the destination is closed.
• D. Never.

Answer: (A)

planning for alternates in IFR flight is about ensuring you have a backup landing option if the destination’s weather becomes unusable. Exemption 3585 loosens the two-alternate requirement in many cases, but it doesn’t remove the need for a second alternate when the forecast at the destination is marginal and the chosen alternate only meets minimum weather requirements. In that situation, you need a second alternate with higher minima to guarantee a viable option if the first backup isn’t usable due to weather or approach constraints. So, the condition described—marginal weather at the destination and an alternate at minimums—is when a second alternate is required.