Final answer:
If your destination airport doesn't have an instrument approach, you will need an alternate airport.
Step-by-step explanation:
If your destination airport doesn't have an instrument approach, you will need an alternate airport.
An instrument approach is a specific procedure that pilots use to land at an airport when the weather conditions are poor or visibility is limited. It requires the use of navigation aids and instruments to guide the aircraft to the runway.
If an airport doesn't have an instrument approach, it means that pilots cannot safely land at that airport in poor weather conditions.
Therefore, the requirement for an alternate airport is necessary in case the weather conditions deteriorate at the destination airport.