Originally Posted by
tdracer
OK, fair enough - but at the time they learned of the closure of the destination airport, they are in the middle of the Pacific. If they were closer to the North American mainland, a diversion to somewhere in North America would make sense. As it was, they were closer to home than they were to the primary alternates.
Absolutely agree with your thinking on this.
Yes, "
Planned alternates are exactly for problems at the destination airport. Weather, closed runways etc.", and obviously become of increasing importance as you approach destination and your options reduce since your diversion footprint is becoming more limited, typically by fuel.
OTOH if you learn that your destination is closed when you are several hours away AFAIK there's never been a requirement to slavishly plod on to any one of your filed alternates (either destination alternate or en-route alternate). In that situation to some extent pre-flight planning, including choice of alternates, that was often done simply to satisfy legal fuel requirements at the original destination, all goes in the bin and you start considering all other options.