How far away can the departure alternate be located for a 2-engine aircraft?

• A. Within 1 hour, in still air with 1 engine inop
• B. Within 2 hours, in still air with 1 engine inop
• C. Within 30 minutes
• D. Any distance

Answer: (A)

The key idea is how far you can place a departure alternate when planning an IFR flight in a twin-engine aircraft. For a two-engine airplane, the rule is that the departure alternate must be within one hour of flight time from the departure airport, assuming still air and with one engine inoperative. This ensures you can reach the alternate quickly if you lose one engine and need to divert soon after takeoff, keeping the plan within a safe, predictable performance envelope.

So the distance is limited to one hour of flying time under those engine-out conditions, which makes the option stating “within 1 hour, in still air with 1 engine inop” the best choice. The other options either propose too long or too short a distance or no limit at all, which aren’t aligned with this planning requirement.