TP 236 - why no great circle route

Old Sep 9, 19, 10:09 pm
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TP 236 - why no great circle route

If you look at the Great Circle map of SFO-LIS, the circle goes into Canada over North Dakota, o er NewFoundland, and drops down the Atlantic into LIS.

But the actual flight 236 basically stays in the US the entire route, skirts of St. Johns, and the drops into LIS.

Is there any reason they donít stick to a more circle route?
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Old Sep 9, 19, 10:35 pm
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I don't have a logic behind it but IB SFO-MAD also similarly follows the routing. I just took a look at GCMAP and it's not too far off from the routing. Could be a traffic pattern or weather pattern related.
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Old Sep 9, 19, 11:20 pm
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What about the reverse? Could be optimizing for the jet stream.
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Old Sep 10, 19, 7:32 am
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The reverse -237 , seems to stay super low, even some days entering the states from massachusetts
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Old Sep 10, 19, 8:15 am
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Originally Posted by returnoftheyeti View Post
If you look at the Great Circle map of SFO-LIS, the circle goes into Canada over North Dakota, o er NewFoundland, and drops down the Atlantic into LIS.

But the actual flight 236 basically stays in the US the entire route, skirts of St. Johns, and the drops into LIS.

Is there any reason they donít stick to a more circle route?
The fastest and most efficient route won't necessarily be a great circle due to wind, traffic, and other considerations (restricted space, bad weather, operational needs, etc).
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Old Sep 10, 19, 3:35 pm
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Almost certainly the jet stream on that specific day. The route of any long-distance flight can vary a lot from one day to another based on wind patterns.
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Old Sep 10, 19, 8:10 pm
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As this is pertaining to a TP flight, we'll move this to the TP forum.

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Old Sep 11, 19, 12:56 pm
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My best guess, avoiding overflight fees in Canada. looking at the actual route over past days, common theme seems to be maximizing the distance flown within US airspace (see 5th of Sep).

If i'm reading the below correctly TP is exempt from any overflight fees within US airspace on that SFO flight

Fees in U.S.-Controlled Airspace

The FAA charges overflight fees to operators of aircraft that fly in U.S.-controlled airspace, but neither take off nor land in the United States.
As soon as they would cross over to Canadian airspace those fees pile-up.
For Canadian airspace there is a charge based on MTOW (basically per aircraft type) and distance See appendix C-2 and C-3 for examples.

Back to the actual route taken, on the 9th of Sep that jet stream must have paid off in less fuel burn vs the overflight fees.
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