[Lou L]

smoke began filling the cockpit, perhaps from a tire on the front landing gear that had ignited on takeoff. The captain immediately did exactly what he had been trained to do: Turn the plane toward the closest airport

If the front tire ignited after takeoff, wouldn't the closest airport be right behind them? That is, the airport from which they just took off?

[KC Burke]

At the link they explain that the analysis takes the originating airport being ruled out into account. 8000 foot ridges are crossed just after take-off and climb to altitude when leaving the main airport. The alternate had an approach without that complication.

Its a good theory and for the sake of the future I hope it turns out correct. Its a straw, but I.m hanging on.