NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Frank Reed
Date: 2024 Dec 16, 20:33 -0800
David C, you wrote:
"I keep a watch on air traffic across the Southern Ocean from Austalia/NZ to Santiago."
Yes, those New Zealand to Santiago, Chile flights are excellent examples of the diversity of options available. Another pair to look at with even more extreme variety is San Francisco to New Delhi.
You're not the only one who was keeping notes on those flights. You mentioned flightradar24, which is a successful, very popular website and app (I use both regularly). There's another nice website, flightaware.com, that collects and displays track data for all flights available, and there are daily changes --a couple of examples attached (if you visit the site, scroll to the bottom of any numbered flight page to find recent flight "history". Sometimes SFO-DEL flights travel fairly close to the great circle and pass over eastern Siberia and Alaska. Other days they fly over Greenland and central Russia. Note that these Air India flights have a commercial advantage over US flights since India has not participated in sanctions against Russia and is able to shorten flight time significantly by flying over Russia. It may be that no other airlines, besides Air India, are currently flying this route direct.
As you note there's a standard that I didn't mention in my previous post that is comparable to flight exclusion zones. It's the "engine out" rules for two-engine aircraft. How long is a commercial airliner allowed to be out-of-range of a safe diversion airport with only one operating engine? The ETOPS limits have been expanded in the past few decades and vary by aircraft type and regulatory authority. There's some detail in the Wikipedia article on ETOPS specifically addressing those Santiago–Auckland–Sydney flights that you mentioned.
Last-minute addition: poking around just now on flightradar24, I see there's a cargo flight outbound from Antarctica (screen cap attached). It's amazing that flights like this are almost routine ...and amazing that we have live tracking on them from anywhere on Earth.
Frank Reed
