Hi,

 

I was wondering how reserve fuel works when you have multiple alternate airports during a flight. I know that the fuel minimums require that you have enough fuel to fly to an alternate airport, but what if you have multiple alternates? Do you need enough fuel to be able to fly to all the alternates or just the closest one?

It's a bit of a minefield this as it's done differently by airlines and aviation authorities so there's no one answer. As long as you have enough fuel to fly your original route, make an approach and go missed, divert to your alternate and then land with your 'final reserve' intact, then you're golden. The final reserve varies depending on the rules, but if you use fuel for 45 minutes flight (not a lot in a big jet!) then you can't go too far wrong.

 

If the weather is bad at the planned destination and the alternate looks dodgy then you'd have multiple alternates. You don't AIUI need fuel legally to get to them but any sensible skipper would be taking a lot of gas on a day like that. If the weather is good all round and nothing untoward is expected, then you can dispense with contingency fuel altogether, provided your final reserve fuel adds up to 45 mins.

 

As I said, it falls into PHD level dispatching which is a lot more complex than it might look. We do a pretty comprehensive overview of dispatching and planning a Trans Con USA flight in our upcoming 777 Program *blantant plug*

You would want to have fuel to get to the furthest alternate, not the closest.