Don your anorak and get technical about airplanes.
#926722 by Solarm
28 Sep 2016, 21:56

Just watching the two flights to Florida today and I began to wonder why the flights are routed in two different paths.

VS 15 LGW to MCO 747 routed north over to the eastern seaboard and then south the VS 5 LHR to MIA 787 looks basically direct over the Atlantic.

there doesn't seem to be any difference in distance or time and the 787 as a twin needs to be within land fall more than the 747 so the routes would seem to be the wrong way round.

Any thoughts/explanations

#926726 by tontybear
29 Sep 2016, 02:09
just because a plane has 2 engines does not automatically mean it needs to fly closer to land.

The 787 is certified to operate within 330 minutes from a diversionary airport.

Some of the route mapping websites show notional rather than actual routes.

Plus there are weather and ATC issues to consider.
#926728 by Solarm
29 Sep 2016, 07:45
Thanks for reply

I completely appreciate your observations

It was just a whimsical ponder of why two flights from London to Florida, taking off at the same time would take such different paths. Weather wouldn't seem to be a determining factor, ATC obviously provided the routes, I was interested if there was a more specific reason , other than a whim of ATC.

Always good to know that a 787 can fly on for 5 1/2 hours after an engine failure especially with the RR issues :-D

#926732 by Hamster
29 Sep 2016, 09:16
Virgin plan their own routes, albeit mostly automated now.

Lots of factors have a part to play in routes taken too, some already mentioned but also things like fuel burn costs, cost of flying within certain airspace areas, minor defects on the actual aircraft and reducing delays to avoid EU comp pay outs! Plus so many more.
#928199 by some guy
02 Nov 2016, 21:59
Not sure about the 330 mins but certainly 180 mins on the 787. It still means you can fly anywhere except remote parts of the south pole and South Pacific.

Regarding routings, here are some factors that can affect route:

1. Cost of fuel
2. Cost of running those engines
3. Cost of overflying certain countries
4. Cost of crew, aircraft and servicing
5. Wind and flight level
6. Operational restrictions
7. Mandatory routing from ATC

We'll never know why the MCO and MIA flight diverged but for the sake of an example, it could be that it was cheaper to operate the 747 (with 4 fuel thirsty engines) over land because it was heavier or didn't have the performance to fly above winds over the ocean. The 787 may have had the performance to climb higher into a lesser headwind over the ocean and, with only two engines, this may have been the cheaper option for that aircraft type on that day with that weight.

Finally, the arrival routing into MCO may have favoured arriving from the north in terms of fuel required. This can trickle back and affect the route 1000's of miles back in the flight plan.

Happy to go into more detail!
Virgin Atlantic

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