<Dl> <Dd> While a flight plan is produced for a specific route, flight dispatchers may wish to consider alternative routes . A flight planning system may produce summaries for, say, the next 4 best routes, showing zero fuel weight and total fuel for each possibility . </Dd> </Dl> <Dd> While a flight plan is produced for a specific route, flight dispatchers may wish to consider alternative routes . A flight planning system may produce summaries for, say, the next 4 best routes, showing zero fuel weight and total fuel for each possibility . </Dd> <Ul> <Li> Reclear selection </Li> </Ul> <Dl> <Dd> There may be several possible reclear fixes and initial destinations, and which one is best depends on the weather and the zero fuel weight . A flight planning system can analyse each possibility and select whichever is best for this particular flight . </Dd> </Dl>

When do you have to file a flight plan