The Aircraft Turbulence Thread reminded me of this:
I was waiting for a bus on Friday after work, and as I watched, I saw no less than seven aircraft leave their cloudy trails at great heights in the sky, to add to the two trails that were already there.
One aircraft passed over relatively lowly, so that I saw the glint of the sun on the aircraft’s body, and I could clearly see the individual streams from each engine exiting into the air and turbulently joining together.
It was clear that the strams were actually moving backwards as they exited, and slowing down as they hit the surrounding air, not just moving forward slower than the aircraft. Interesting and oddly beautiful.
There seemed to be a lot of aircraft in the same general area at the same time. I was about 15 km southwest of the Toronto airport at the time; my first thought was that they were going to or from the airport, but aircraft arriving and leaving Toronto follow definite paths* at much lower altitudes.
These planes were all high up and moving in completely-different directions.
My question: Is there some kind of junction of the airways that leads a lot of planes to pass high over Toronto? Or was this just a random occurrence, just “ships that pass in the night”?
Such as about a hundred metres above the intersection of Derry and Hurontario. You can practically count the rivets.
Large jets fly what are known as Jet Airways, and there are definite intersections that all aircraft on instrument flight plans will fly directly over.
These intersections are typically determined by bearing and distance from various radio navigation beacons, or sometimes by flying directly over a beacon.
When taking off or landing at an airport, aircraft fly published ‘approaches’ which start at one of these intersections and then proceed inbound to the airpot, or they fly a published departure which may have them fly the runway heading until they reach a certain intersection, at which point they will turn onto the heading which takes them onto the airway for the flight.
Smaller aircraft flying visual flight rules can just fly direct from point A to point B, and don’t have to worry about the airways or intersections. They may still tend to congregate in small areas, because there are “VFR Reporting Points” in most controlled airspaces that are usually prominent landmarks on the ground.
It may look chaotic from the ground, but IFR aircraft are separated by a lot of distance, and are stacked into horizontal planes 2000’ apart. So even if it looks like two airplanes are heading directly for each other, there will be be at least a 2000’ vertical separation between them. You just can’t see that from the ground.
Toronto? Try the Gulf of St. Lawrence around Anticosti Island. Most days it looks like a freakin’ plane freeway up there.
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