Well, it's not so much that the flight path is 'curved', but the map is distorted. If you viewed the path on a polar stereographic projection it would be much more a straight line (and give you a better idea of deviations from a direct route due to jet streams/etc).

You mean she charges by the hour?

FWIW, the shortest (ie great circle) route from LHR to LAS can be seen here: Great Circle Mapper

Start with the great circle route, and adjust for winds. For example, I took BA48 a couple of months ago SEA-LHR. It usually heads straight NE over Canada, but the winds that day were more favorable for going E to North Dakota (ground speed of 700 knots, according to the map on the IFE) before turning north to catch the track over the Canadian Arctic/Greenland/Iceland to the UK.

But start with a globe and a piece of string.

Looks like a pretty straight line to me.

https://skyvector.com/

I stumbled across this site the other day, with the North Atlantic tracks shown, along with other routes/paths/corridors.

Ah - rather an idealised great circle example...

Below is BA 285 LHR-SFO on 9th Dec - the first mapping is an equal area, the second a Mercator....



Things to note that all equal area projections aren't really equal area (!), and while Mercator is often used, it's terrible at representing the higher latitudes!

BTW - you'll probably notice (or find out) that for TATL flights westbound tend to be on more northerly routings to avoid the (headwinds of the) jet stream, while the eastbound services tend to be further south take advantage of the jet stream (tailwinds).

With regard to jetstream taken into account of the flightpath, here's a map for that route (updated every 4h):
https://earth.nullschool.net/#curren...0.74,51.96,503

Many years ago when I did a lot more flying, I was on a flight with a new colleague going to LOS. He asked why the flight time returning to LGW at the time was longer than the outbound to which my quick and witty reply was �because we�re going uphill going back�. His answer being �Oh, that makes sense� 😬

S

A despatcher once told me flight routes are also designed so that they are never more than an hour's flying time from an airport, as much as possible. So flights across South Atlantic fly close enough to the Azores. Not sure if I remember details absolutely correctly.

Said dispatcher is misinformed I'm afraid.That would burn too much fuel.Most long haul twin engine aircraft are certified for 3 hours from a diversion airport at single engine cruise speed/mach.

That's true for most two engined aircraft which are not rated for extended operations (ETOPS). You need to be within 1 hour diversion flying time on one engine to an airport. Obviously for flights across Europe is isn't an issue. However, I would imagine most aircraft used regularly for trans ocean flights would have a more relaxed requirement. A number of aircraft can be approved for ETOPS ratings where the flying time can be a lot more than 1 hours. Typically I think ETOPS 180 is common - so you can route such that you are within 180 minutes one engine flying time of a diversion airport at all times. Higher ETOPS ratings are possible to I believe.

ETOPS 180 aircraft can be wide bodies such as 777/A330, and narrow body aircraft can also be rated higher. AA uses specific ETOPS rated A321 aircraft from LAX/PHX to Hawaii for example, and BA's babybus would be ETOPS rated.

Probably better explained here https://en.wikipedia.org/wiki/ETOPS the diagram makes it a bit easier to understand.

OK that would explain it. My friend dealt with small private jets.

Hi everyone!

A friend of mine has just pointed me to a strange flight path of this flight (UKL4076) that has been waking him up, always taking this same route. The aircraft takes off from Izmir and the destination is always indicated as Kiev, Ukraine but just before there, it takes a sharp turn to later land in Liege, Belgium. This is supposed to be a military-registered aircraft so, being a total ignorant, I am just wondering whether this is common practice or there really is something strange about it.

I will appreciate any input! :-)

Damn - sorry KARFA - for some reason didn't spot your above post. Apologies.

Predictably it's a bit more complicated than that. There are all sorts of protocols for this but one that you may often see reference to is ETOPS, which stands for Extended range Twin engine Operational Performance Standards. Basically a set of operating procedures to allow twin engined airliners (where the issue or a single engine failure over water / ice is more serious than in a 4 engine bird) to operate safely.



In addition to the requirements about flight time to emergency / alternate fields (which are defined as permitted maxima at single engine cruise speed, based on the exact ETOPS certification the plane has) there are also as I understand it extra protocols around maintainence checks etc. The aircraft even have ETOPS painted on the undersides in strategic spots just so, when they're in hangar getting a look over, there's no confusion as to what needs inspecting and to what level of detail.

So in theory a non ETOPS certified plane shouldn't be flying an ETOPS routing. AA got in trouble with this a while back flying LAX to HNL and had to get another bird out there for the return.

Apparently in aviation slang it can also stand for 'Engines Turn Or Passengers Swim'. Got to love that. But it is not specifically a ruling about flights over water as I understand it - the assessment is on flight time to a suitable alternate. And therefore there are also standards for 4 engine planes (typically ETOPS 180 I think).

As you'd imagine there is lots online on this. The above is merely a summary of the small amount I know about it. If I got any of this wrong, experts please feel free to correct (gently please haha)

There are no etops requirements for 4 engine aircraft.The only requirement is for a suitable alternate.This can be limited by fuel required at 3 engine cruise such as on a trans pacific flight,or sometimes an oxygen limitation if far from anywhere and in the event of a decompression.