A couple of days ago I wrote about how an Air China flight bound from Hong Kong to Dalian rapidly descended by 25,000 feet after the cabin seemed to lose pressure, causing oxygen masks to deploy. This happened about 30 minutes after takeoff, though the pilots ended up continuing the journey to Dalian, and climbing back up to a higher altitude.
There are some updates to this story, and two points that are very, very problematic.
A vaping pilot is to blame for this incident
There were rumors that a smoking pilot may have been to blame for this, though at the time it wasn’t clear what the connection was between the smoking and the supposed depressurization. Now we know.
A senior official with the Civil Aviation Administration of China has told reporters today that the first officer on the flight was smoking an e-cigarette, and wanted to turn off the air recycling fans to prevent the vapor from spreading into the passenger cabin. Instead he accidentally turned off the air conditioning in the cabin, which created the sensation of depressurization.
Initial reports suggest that he did this all without telling the captain (though that doesn’t mean the captain should be off the hook — logically he should have told the first officer not to vape, though unfortunately this seems to be an acceptable part of cockpit culture in China).
Continuing the flight to Dalian was reckless
The smoking situation is bad enough, though the reality is that it’s far too common in China. As far as I’m concerned, the bigger issue is how the pilots responded to this — they chose to continue their flight for hours with oxygen masks deployed. Oxygen masks have a limited amount of oxygen, and once they’re deployed, they release oxygen until they run out.
The plane kept flying for over two more hours, so you can bet that for a majority of the flight there was no emergency oxygen supply. If there were another emergency, people would have been in serious trouble.
There were even reports that towards the end of the flight the crew once again made an announcement telling passengers to put on oxygen masks, though that was quickly dismissed as a false alarm. Imagine if it hadn’t been, though, and the passengers needed emergency oxygen, only to find that there wasn’t any.
As a reader commented on the previous post:
Once the passenger masks deploy, assuming the passengers pull down and put them on (as we’re all told to do before every flight), the chemical reaction that generates the oxygen starts. After about 15 minutes, there is no more passenger oxygen. Ascending above 10,000 feet after the masks deploy is super unsafe because you have no margin of error if you lose cabin pressure at high altitude (though the pilots would be fine; they have a separate oxygen system).
This happened in the US back in 2000 on an Alaska 737. The pilots forgot to pressurize the plane, and when they crossed 10,000 feet alarms went off. At 14,000 feet, the masks deployed. The pilots realized their error, pressurized the cabin, and continued the flight, with masks dangling. The pilots were both fired, and the main reason they were was not so much for failing to pressurize the cabin, but for continuing the flight with no emergency passenger oxygen. Totally against procedures, and potentially fatal if the plane lost pressurization later. I suspect something similar may have happened here.
Now that we have some official information from investigators, we have a better sense of what happened, and this is really screwed up. The vaping first officer is bad enough, though the reality is that smoking and vaping in the cockpit on Chinese airlines is extremely common. The fact that the first officer tried to cover it up in such a reckless way is troubling.
But the way I see it, the most concerning thing that happened here is that the pilots continued the flight for several more hours without any emergency oxygen supply, with oxygen masks deployed. That’s an area where the captain is just as much at fault as the first officer (if not more at fault, since he’s the final authority).
(Tip of the hat to @DanGare)