Alternate Airport

An Alternate Airport is an airport designated in the flight plan to which a flight may proceed when landing at the intended destination becomes inadvisable due to weather, runway closure, emergencies, or other factors.

IFR flights generally require a destination alternate if weather at the destination is below certain minima. There are also takeoff alternates (in case of engine failure after departure) and en-route alternates (for ETOPS flights).

• Must meet minimum weather criteria at the estimated time of arrival
• Must have suitable runway length and available approaches
• Fuel planning must include fuel to reach the alternate plus reserves
• ETOPS flights may require two en-route alternates within diversion time limits