Can commercial airliners fly over central Antarctica during winter?

Question

For example, if an airline decided they wanted to run year round flights on the great circle from Perth to Buenos Aires with a commercial airliner (e.g. A380 or B747), would they be able to do so? Or would it be too cold to fly?

I'm aware that there are a few sightseeing flights during the summer over Antarctica, but the winter temperatures in central Antarctica are lower than anywhere else on Earth (with surface air temperatures occasionally reaching around −90 degrees Celsius).

Edit: To clarify, by "winter" I mean the coldest time of year, i.e. roughly May to September.

Answer 1

Surface air temperatures aren't really going to be relevant for an airliner. The temperature of the troposphere doesn't vary that much. In fact, the troposphere is warmer at the poles (from Wikipedia Troposphere):

At middle latitudes, tropospheric temperatures decrease from an average of 15 °C at sea level to about −55 °C at the tropopause. At the poles, tropospheric temperature only decreases from an average of 0 °C at sea level to about −45 °C at the tropopause. At the equator, tropospheric temperatures decrease from an average of 20 °C at sea level to about −70 to −75 °C at the tropopause.

Sightseeing flights are indeed run during the summer months, but that is because it's actually possible to see things, not because it's any warmer. It wouldn't be very interesting to do a sightseeing flight in darkness.

The biggest obstacle to doing winter commercial flights over Antarctica is the lack of suitable alternate places to land in the event of an emergency.

Answer 2

They could, if only they were allowed to.

From

§ 121.161 Airplane limitations: Type of route.

(a) Except as provided in paragraph (e) of this section, unless approved by the Administrator in accordance with Appendix P of this part and authorized in the certificate holder's operations specifications, no certificate holder may operate a turbine-engine-powered airplane over a route that contains a point—

(1) Farther than a flying time from an Adequate Airport (at a one-engine-inoperative cruise speed under standard conditions in still air) of 60 minutes for a two-engine airplane or 180 minutes for a passenger-carrying airplane with more than two engines;

(2) Within the North Polar Area; or

(3) Within the South Polar Area.

However, AC 120-42 contains a rationalle on minimum range operations, and explains that twin engine range restrictions started a long time ago, and that turbine engine technology is now so reliable that number of engines is not the limiting factor anymore. From 202 b.:

All long-range passenger-carrying airplanes, regardless of the number of engines, needed a viable diversion airport in the case of onboard fire, medical emergency, or catastrophic decompression. Ensuring availability of en route alternate airports, adequate fire fighting coverage at these airports, and fuel planning to account for depressurization are sound operational practices for all airplanes, including three- and four-engine airplanes.

And AC 120-42 202 mentions that it may be possible for airlines to cross the Antarctic region in the following circumstances:

c. Those areas not supported within 180-minute diversion authority tend to be routes over remote areas of the world that are uniquely challenging to the operation. These areas include the South Polar Region, a small section in the South Pacific, the southern South Atlantic Ocean between South America and Africa, the southern Indian Ocean and the North Polar area under certain winter weather conditions. The additional operational challenges of these routes are equally demanding of all airplanes, regardless of the number of engines, and include such issues as extremes in terrain and meteorology, as well as limited navigation and communications infrastructure. Support of a necessary diversion and subsequent recovery in such areas demands added training, expertise, and dedication from all certificate holders.

I could not find any direct flights from Australia to Buenos Aires, all go via New Zealand or further. And those flights would avoid the shaded areas on the map I would imagine.

This answer has looked at the flight path of a Qantas flight from Sydney to Santiago, which uses Tahiti as a diversion airport. A flight over Tahiti is much more northern: