Air China Flight Rapidly Descends 25,000 Feet – Were Smoking Pilots At Fault?

Filed Under: Air China

On Tuesday night, Air China flight 106 bound from Hong Kong to Dalian lost pressure in the cabin, causing the plane to descent 25,000 feet in 10 minutes. While that’s obviously a significant descent, I’d note that 2,500 feet per minute isn’t that extreme. In reality it would feel like a steep descent, and not like the plane was falling, or anything. The flight was operated by a four year old Boeing 737-800 with registration B-5851.

Oxygen masks in the cabin deployed after the plane lost pressure about 30 minutes after takeoff from Hong Kong. The plane descended from 35,000 feet to about 10,000 feet, and then eventually climbed back up to a higher altitude to complete the 1,200+ mile flight, though it did stay below 30,000 feet for the remainder of the flight. I guess they determined that it was safe to continue the flight, though it must have been odd to fly for nearly another three hours with the oxygen masks deployed.

We can’t judge the pilots’ actions here until an investigation is completed, though typically you’d divert if a cabin depressurized in this way, out of an abundance of caution, if nothing else (not to mention that it’s really odd to fly with oxygen masks deployed). That’s not to say the pilots necessarily did anything wrong (that remains to be seen), but rather that more often than not that’s what happens.

What’s perhaps most interesting is what some claim is behind the incident. Danny Lee at the South China Morning Post reports that Air China has vowed “zero tolerance” if the crew is found to be at fault. The People’s Daily reports that the pilots are suspected to have been smoking in the cockpit. I’m not sure the connection that has to the depressurization, though it does bring to light a common concern I’ve had with some Chinese airlines.

I’ve written in the past about how smoking in the cockpit seems to be a common occurrence on some Chinese airlines. Smoking for passengers is strictly prohibited, while in Chinese cockpits it seems quite common. It does seem like there are some potential safety issues with pilots smoking in the cockpit, so it will be very interesting to see what comes of this investigation, and in particular, if we see the Civil Aviation Administration of China finally cracking down on this practice.

This will be an interesting one to watch…

  1. Smoking in the cockpit = open the cockpit window to vent = depressurisation warning.

    Wouldn’t be the first time.

  2. Oxygen generators in the plane only have enough capacity for a few minutes, maybe 15. If the oxygen masks were used for hours, it was just for show.

  3. @Derek
    You are right. Oxygen mask released and not enough oxygen. Crew shouldn’t continue flight without enough oxygen for another two hours. They should divert. Big mistake after the first one.

  4. Can’t trust the Chinese. They lie and lie and lie and steal. No wonder Donald trump likes them.

  5. Who cares if they smoke in the cockpit; it’s of zero significance. The only problem…ever… from smoking on planes was as a consequence of the smoking ban, and some idiot decided to smoke in the lavatory and dispose of the cigarette in the paper towel bin.
    I say : let the pilots smoke if it keeps them relaxed and awake.

  6. @Derek

    I don’t think Lucky was implying they were used for hours, but once they deploy they are pretty difficult to put away so they would have been swinging around the whole flight.

  7. @Jason – The first rule of cover up is to keep going for as long as you can so the CVR data will not incriminate you.

  8. Lucky – I know this is off-topic, but you should totally review Shenzhen Airlines’ new long haul service from Shenzhen to Heathrow. A quick Google revealed that their business class looks… Interesting. Maybe you could combine it with a Beijing Capital Airways review from London on the way back?

  9. @paolo smoking in the flight deck is just as dangerous. A misplaced cigarette dropped during an emergency. A ban should mean the entire aircraft. The vast majority of people who are aware there is a ban also assume it extends to crew
    Carelessly dropped cigarettes cause wildfires and deaths on the ground
    Furthermore I along with many others, can smell the smoke even if it comes from behind a closed door
    The residue on the equipment and walls
    The stink of cigarettes on clothes and breath
    Hotels may have non smoking rooms , so you the next crew may not wish to occupy a space where someone smoked

  10. Cant climb back up after oxygen mask drops. Once pax pull their mask towards them, oxygen will be produced in that individual mask. It last only until the chemicals in that mask are out. Supply last at least 12 minutes, and the process cant be stopped.
    So climbing up again leave the pax without oxygen supply in the event of another decompression.
    Those pilots will not set their feet in an Air China cockpit again, provided the story is true.

  11. @Chris_IOW I think the point is that, once deployed, the oxygen masks were depleted. What if there was a true depressurization event afterwards? There would be no emergency oxygen in the cabin and people would suffocate while the pilots descended.

  12. @djibouti Exactly! These things don’t provide oxygen for long and once deployed, that’s it. If the plane had lost pressurization/ oxygenation a second time, it’d have been lights-out for everyone. I can’t imagine how this plane was allowed to continue its flight back at a cruising altitude.

  13. Mark nails it. 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.

  14. @djibouti

    Absolutely agree, I wasn’t trying to suggest the actions were anything other than recklous, simply that no one was suggesting they spent 3hrs using the masks!

  15. Lucky, you really need to get over this whole issue with smoking. You are a blogger about airlines, not an anti-smoking activist. You took ONE flight on a Chinese airline where the pilots smoked (according to your nose, you never actually saw them smoke). Now, in this article, you have conflated that one experience into a broad, generalised assertion that ALL Chinese airlines have a problem with pilots smoking — something you have no evidence of beyond that single flight. Your comments are not only wildly exaggerated, but it is also racist to now paint all Chinese airlines with the same derogatory brush. Your articles are generally really great, very helpful and I read them every day. But your periodic whining about smoking makes you sounds like a pampered, spoiled little brat from the first world, sitting in first class.

  16. @Derek Glass
    Oh if you fly regularly on chinese airlines you would know pilots smoking is not an isolated incident. You don’t even need statistics.

  17. @Paulo – Filling up a cabin with poisonous, revolting smoke is indeed a “problem”. Only an arrogant scum-bag would think otherwise.

  18. I regularly smell cigarette smoke on China Eastern. Whatever keeps them awake is fine by me.

    Once oxygen masks are deployed climbing back to cruising altitude is a big NONO.

  19. Shocked at how many people are unphazed by pilots smoking in the flight dec. Both local and global authorities must come down hard on this.

  20. For those of y’all who are curious I just pulled up the Flightradar24 data. CA106 climbed normally to 35,000 feet and at 11:37:15 it leveled out at 35,025 ft for 64 seconds then descended, arriving at 10,050 ft at 11:49:51. It held at 10,050 ft for three minutes then started climbing until 11:56:53, when it reached 14,825 ft and leveled off for 30 seconds, then climbed to 16,725 ft at 12:00:32 and held that for 66 seconds, then climbed to 24,600 ft at 12:07:13 and held that for 35 minutes until climbing to 26,600 ft at 12:44:36. It held that altitude for 2 hours and 20 minutes, when it descended normally into Dalian.

    26,000 ft is generally considered the highest altitude capable of sustaining life, so this seems like a particularly high altitude to continue at after a depressurization warning and only about five minutes at completely safe altitudes. If they had continued at or below 18,000 feet or paused a little longer while climbing back up I’d certainly have more confidence in their decision, but this is suspicious.

    Also, @Derek Glass et al, Ben grew up flying between Tampa and Germany in the smoking section with his family, so I’m sure he understands the concept of smoking safely on a plane better than your average young blogger. Be nice, y’all.

  21. 2500 feet descended per minute doesn’t seem significant, but your assumption is based on an average over 10 mins. More likely that it was a steeper descent than that at some point during those 10 mins.

    Smoking on the plane is gross but super common in pre 80s and even part of the 90s. I don’t consider it to be a safety issue on a flight, a health issue sure.

    Big variance in service and quality of Chinese airlines. As they compete for the same routes in the future, one hopes the worst of them will either disappear or make huge improvements.

  22. @schar
    Two other Chinese airlines, both based in Taiwan (officially, the Republic of China) – EVA air and China Airlines – are good to fly too.

  23. If I made to inhale your cigarette smoke I should be allowed to force you to smell armpit wherever and however long I feel like.

  24. @Paolo, Smoking=a fire somewhere. Fire onboard an airplane while an aircraft is 35,000 in the air is never a good idea. A captain drops a cigarette, who knows? Look at Valujet 592, and nobody was even smoking!

  25. Lucky honestly this is a really irresponsible piece. Maybe some uninformed Chinese news outlets speculates about pilots smoking, but do you need to re-broadcast this nonsense? I don’t think that in the history of aviation there has been a single crash due to smoking. Before the 90s smoking was common – and planes weren’t falling out of the sky then.

  26. Looks like the co-pilot was vaping, which caused the ac to automatically shut:

    “”In the preliminary investigation, the co-pilot was found to be smoking an e-cigarette,” state-owned China News said, citing a news conference by the Civil Aviation Administration of China (CAAC) investigating Tuesday’s incident.

    “Smoke diffused into the passenger cabin and relevant air conditioning components were wrongly shut off, without notifying the captain, which resulted in insufficient oxygen,” it quoted Qiao Yibin, an official of the regulator’s aviation safety office, as saying.”

    As I said – it’s long overdue to come down hard on smoking – and vaping – anywhere on the plane, including (if not mainly!) in the cockpit.

  27. BBC : Seems co pilot was vaping and tried to hide it and shut off ac in error
    Smoking has been prohibited by all including crew in China since 2006. Perhaps tell this to China eastern

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