Is it possible to take off and then fly ONE course over very long routes (like JFK-London)?

Question

In other words: could you take-off in JFK, then fly a heading of something like 090, and then for the whole trip, you fly only this one heading, until you arrive in London. Possible, or DO you have to make some (small) curves?

Answer 1

If you went straight east, you would arrive in Portugal or Spain.

Answer 2

Most long haul routes (and probably some shorter ones as well) follow what are called Great Circle routes.

Those are the equivalent of straight lines on a sphere.

Assume the globe is sphere, which is close enough for our purposes here.

Think of it this way:

Tie a string or rubber band around the globe at the equator.

Now, keeping the string stretched, move it around until the origin and destination of the journey lie under it.

That gives you the Great Circle route, which is the shortest one.

In following it, you are going in the "same direction" all the time, but in terms of N,S,E,W it may change in description.

For example, a flight from LAX to LHR starts out going Northeast, but at some point reaches a farthest point north and then starts going Southeast, without actually changing its heading.

JFK-LHR would be more directly east and the effect would not be as great.

Answer 3

It is possible to fly a rhumb line course from JFK to London.

Some rhumb line course formulas (in radian, not degree, measure) are at the online "Aviation Formulary" website.

Answer 4

Yes, you could do this but it would be a longer route than if you flew a great circle route.  Determining this heading, since the magnetic variation is constantly changing would be a challenge, however in theory it is possible.