Title text:
We should have you at the gate in just under two hours–two and a half if we get pulled over.
Transcript:
Transcript will show once it’s been added to explainxkcd.com
Source: https://xkcd.com/3124/
Title text:
We should have you at the gate in just under two hours–two and a half if we get pulled over.
Transcript:
Transcript will show once it’s been added to explainxkcd.com
Source: https://xkcd.com/3124/
why was it cold, because they couldn’t maintain an internal cabin atmosphere, including temperature?
Also, I had to look it up, but just wanted to confirm 7000 feet is much lower than typical 737 cruising altitude, which is usually 30,000 - 40,000 feet.
7000 feet is still pretty high and around where oxygen saturation decreases - could you tell any effect? I just assume they were able to still oxygenate the cabin even if they couldn’t go as high 🤷♀️
No pilot or Jet mechanic but afaik the pressurisation is happening with bleed air from the turbines that is then cooled down to comfortable levels. So there is no “heater” for the cabin so to speak as for a warmer cabin you just cool down the bleed air less. As such without pressurisation there is also no cabin heat.
You just casually knew that offhand, and it’s not even your industry??
I am weirdly nerdy about planes. Always wanted to be a pilot as a kid.
7000 ft is relatively common for small planes like cessnas, they don’t even keep pressurized cabins, but It’s fine if you stay low. So there’s nothing wrong with that altitude, but it’s awfully low for a jet. The jet will be flying at low fuel efficiency the whole way and it certainly won’t have much wiggle room if something really goes wrong. (You can lose 7000 ft of altitude very quickly)
ah, I wasn’t sure because I was reading this:
https://en.m.wikipedia.org/wiki/Effects_of_high_altitude_on_humans
it seemed like between 7,000 and
8,00026,000 the air is not suitable, but I figured the pilot wasn’t likely to be taking risks like that, so there must be some explanationedit: mixed up feet and meters
actually, cabins are typically pressurized to around 10,000 ft, not sea level, iirc. so this was actually a higher pressure than is typically experienced in a pressurized cabin.I’m wrong
I got mixed up. the limit for unpressurized cabins is 10,000 ft, so if you’re flying a small plane without supplemental oxygen you can’t go higher than that
Do you have a source for this? My only reference here is hiking at > 10 000 ft (3000 m), and from that I can say that this seems very unlikely: If you stay at 3000 for a couple hours without acclimating first, you will definitely start to feel the effects. To be fair, you’re usually not moving around a lot in an aircraft, but a couple hours at 3000 m can make you feel sluggish and weak, and even a bit light-headed, you could even get a mild headache from oxygen deprivation.
Note that not everyone will see severe symptoms already at 3000 m. Plenty of people can go to 4000 m before seeing significant symptoms. However, given that I’ve never heard of anyone experiencing altitude sickness in a properly pressurised aircraft, it seems unlikely to me that they’re pressurised to 3000 m.