If you were sitting on this airplane (below) waiting for take off, would you be as seemingly calm as the passengers in the picture?

jfk airplane fog

(Photo: Imgur)

Perhaps you’re wondering why no one is attempting to frantically exit the plane or why those oxygen masks haven’t dropped from the ceiling.

The image, taken by a passenger on the flight this week out of New York’s John F. Kennedy airport, isn’t actually showing smoke. As the redditor fliccolo states on the social news site, it’s fog.

“It’s the ac pumping out fog from going thru [sic] a bunch of rather violent storms so hot air/ cold air combo of instant interior clouds,” fliccolo wrote.

Another redditor explained more about what’s going on:

For those wanting to know how aircraft ac works: Basically air is bled from the engines about halfway of its compressor stage and is about 400F or 200C degrees.

Obviously this needs to be brought down. This happens in ac unit that uses the outside air that is pretty cold. On the ground and low altitudes a fan is also driven by the hot air for extra cooling. By doing this extra energy (read heat) is taken from the engine bleed air. After the cooling process the air should be around 7c or 45f. Great for cooling. But at flight level air needs to heated. This can be done by several methodes [sic].

Most common is taking the air after the first cooling radiator, which now is pretty hot, and use a second point to slightly heat the air going into the cabin. Also note that the outside air and the Engine bleed air that is going into the aircraft never physically mix. All cooling and heating is done by radiators, and regulated automatically by the airco pack. The flight crew can only tell how hot or cold they want it to be.

[...]

Also all AC unit’s in a aircraft have a water-separator of some sort, so i’m still wondering how that much fog got into the aircraft

Fliccolo later explained that the fog stuck around until the plane reached cruising altitude.

“It was at the top of my chest sitting down. I’m of average height so… It was freaky,” he wrote.

Fliccolo said other passengers were a bit perturbed by the otherwise harmless fog as well.

(H/T: Daily Mail)