Here's a breakdown:
* En route: This refers to the portion of the flight between the departure airport and the intended destination airport.
* Alternate: This refers to a different airport chosen as a backup plan.
* Why needed: An en route alternate is needed because:
* Weather: Bad weather conditions like low visibility, thunderstorms, or strong winds can make landing at the intended destination unsafe.
* Other emergencies: Technical issues with the aircraft, runway closures, or other unforeseen circumstances might make landing at the original airport impossible.
When is an en route alternate required?
Regulations dictate when an en route alternate is required. Generally, it's necessary when:
* Weather at the destination is below a certain minimum: This varies depending on the airport and the type of aircraft.
* The flight is expected to arrive at the destination after a certain time: This ensures the pilot has sufficient time to divert if the weather at the destination deteriorates.
Choosing an en route alternate:
Pilots consider various factors when selecting an en route alternate:
* Distance: It should be within a reasonable distance from the intended destination, allowing for safe diversion.
* Weather conditions: The alternate airport should have suitable weather conditions for landing.
* Runway length and availability: The alternate airport should have a runway suitable for the aircraft and should not be closed or under construction.
* Fuel requirements: The pilot must consider the fuel needed to reach the alternate airport and continue to the final destination if necessary.
In summary, an en route alternate is a vital safety measure that ensures pilots have a safe landing option in case of unforeseen events at the intended destination airport.