Originally Posted by
quintic
I was checking the UA89 flight status today, and found it flying eastbound. I though it is used to be westbound transpacific flight. Is it common? How does the airline/pilot decide which way to fly?
It's actually northbound over the pole. Depending on how the wind alot is blowing on that day, the initial heading out of EWR is often slightly to the east. (Wind aloft between 40N-65N lattitude can be very strong west to east, particularly in the winter months).
One example EWR-PVG flight a few years ago:
