When is a second alternate required?

• A. If destination weather is <1,000 ft and 3 SM AND first alternate is <600 ft and 2 SM
• B. Always
• C. Never
• D. Only if fuel is insufficient

Answer: (A)

In IFR flight planning, you set up alternates so you’re never left without a viable landing option if weather turns worse. A second alternate is required when both the destination and the first alternate are forecast to be below the typical minimums that would let you land safely using instrument approaches.

The rule uses common minimums: if the destination is forecast to have less than 1,000 feet of ceiling and 3 miles of visibility, and the first alternate is forecast to have less than 600 feet of ceiling and 2 miles of visibility, you must designate a second alternate. This ensures you have a reliable backup beyond the destination and the first alternate if conditions don’t improve.

That’s why the scenario described matches the requirement: deteriorated forecast at both the destination and the first alternate triggers the need for a second alternate. The other options don’t reflect this specific weather-based planning rule.