FlightAware Discussions

Question about significantly different trans Pacific route

New user, joined just to ask this question that has been gnawing at me for the last week!

On March 1, 2021 I flew KAL18 from LAX to ICN. I’ve made this same flight probably a dozen times and always take the right side of the aircraft to look down on the Aleutian Islands, Alaska, Kamchatka, etc. As a former navigator, I’m well aware of great circle navigation. But this particular flight took flew the same latitude for most of the flight, never making it north of the California-Oregon border. The difference in flight paths is so radical that I can’t imagine it could have been very fuel-friendly, and I also noticed that the SOG was around 450 rather than the typical 550 or so. The flight time was 13:41 which isn’t much longer than average, and in fact, the next KAL 18 flight took a great circle route and the duration was 13:55.

Can anyone explain why this might have been done and, also, how the heck did we make it across in less time than the great circle route.

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What were the high altitude winds or the jetstream doing at the time? They can have a huge impact on routes.

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I don’t know, but that sounds like the most plausible explanation. Thank you for your response.

That’s exactly what I was thinking. Jet streams are a bit unusual at the moment I think, hence the weird weather.

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Here’s the winds at just under 40,000 feet on March 1. Some calm areas in the middle of the Pacific.

Remember that there are rules for staying within x hours of an suitable airport, depending on how many engines the aircraft has. The aircraft is listed as a 777-300ER which only has two engines. The lighter wind route may have forced it to go closer to Hawaii to be close enough to stay within the rules.

It looks like it is back to its usual route today

Good one. Thanks for that! Now I know!