Final answer:
When weather conditions are not suitable for landing at the destination airport but are suitable for takeoff, a pilot must file an alternate airport.
Step-by-step explanation:
When flying for a 705 Operation, if the weather is above the takeoff minima but below the landing minima for all runways, the pilot is required to file an alternate airport.
An alternate airport is a backup airport that meets the legal requirements for the landing minima. It must be within a certain distance from the destination airport and have its own takeoff and landing minima that are within the limitations of the aircraft and pilot qualifications.
For example, if the weather is below the landing minima for the intended destination airport, the pilot may need to divert to the alternate airport to ensure a safe landing.