It was the co-pilot, actually. So long story short, one of the pilots wanted to smoke from his vape device. He didn’t want passengers to smell the smoke, so the co-pilot closed the ventilation system for a minute so the smoke would stay in the cockpit. That’s where it all went wrong though, since he didn’t actually close the ventilation system.
What the co-pilot did instead was accidentally shut off the entire air conditioning system for the whole plane. You might think “well that’s ok, the passenger will just be warm for a few minutes.” No, actually, since when the air conditioning was shut off, oxygen levels in the plane started falling. Oxygen wasn’t being pumped in like normal. That’s when the plane’s computers assumed there was some sort of depressurization. Suddenly, the pilots were plunging in elevation, as per standard in depressurization events. The plane dropped 25,000 feet in just 10 minutes.
Oh, on top of the rapid descent, the oxygen masks deployed too. Now let me just say, no matter the situation, when the masks come down, it’s scary. Especially as you’re falling 25,000 feet in just 10 minutes. That’s about 28 miles per hour, down. That doesn’t seem that fast, but that’s fast. Good news though is that nobody was hurt, and the flight was able to continue to its destination. There’s no smoking on airplanes for a reason, folks,. and that includes vaping too. See some more info on the story here.