by DaveSims » Thu Jan 14, 2010 10:23 am
For the big tubes, usually the dispatcher who plans the flight picks the alternates. It will often depend on weather at any approved alternates and many other factors. I once was on a 757 that diverted from Denver to Grand Junction because of weather, which seemed odd at the time. We even had a situation recently here where an aircraft went missed here, could not even shoot the approach at the alternate, and the pilot and dispatcher spent a few feverish minutes trying to decide what to do next, since fuel is not a replenishable resource.
In real life, the airlines are not allowed to even fly the approach, unless the reported weather is at or above minimums for that approach. A standard ILS is usually 200 feet and 1/4 mile.
