If the descent was controlled gliding, the passengers (at least some of them) should be alive upon landing, shouldn’t they? Where are they now?
Which theory could explain the absolute silence?
Even if all passengers were alive at the time of a water landing, getting out of a plane is tricky in the best of conditions. Getting out of a damaged, rapidly sinking plane is very hard or maybe impossible.
Also, if you would get out of the plane, you are then in the middle of the indian ocean with just your life vest and the sharks. You get maybe 3 days, because the water is warm.
And nobody will find you if they don't know where they should be looking. An airplane life vest doesn't have an AIS transponder, only the life rafts/emergency slides do. If those weren't properly deployed, no chance of a vessel finding you. There are reports of shipwreck survivors about ships passing within a few hundred meters of them in calm seas, and failing to see them.
When you get a sailing license, you learn that if a man goes overboard, it's best to be (at east) three. One goes overboard, one orders the other never to let the overboard man out of sight and to point with his arm outstretched in his direction, and the boatman uses the outstretched arm to the man overboard. It is impressive how quickly you lose sight of someone even in light waves.
This is absolutely correct, but is in part due to the complicated nature of getting a sailing vessel to a fixed location in the sea behind the current location of the boat and in such a manner that allows for the boat to be put directly into the wind at the right time to kill forward motion.
Only very small motor boats are agile enough that you can turn on a dime and not loose sight of a man-over-board. And even then, it strongly depends on wind, current and boat speed. Also, orientation on the seas, sense of direction and getting to a remembered position again is very very hard to impossible. Especially when agitated. You might try using compass and GPS, but those are imprecise, overwhelming and useless when there is any kind of waves or current.
It is absolutely vital to keep the man-over-board in sight. Practically no exceptions.
It's possible for the pilot to depressurise the plane and use their dedicated oxygen system to breathe while everyone else on board will pass out after using their individual masks.
Doing so will give them 60-90 minutes of extra air, the passengers' masks don't last that long.
What legitimate reason would a pilot have to depressurize a plane at altitude, incapacitating or killing the passengers? Just wondering if and if so why that system / function is available.
If some part of that system was on fire or an engine was damaged and it was pumping smoke into the cabin. Basically every system can be switched off, sometimes it’s necessary to be able to switch them off completely (normally for pressurisation they would already be on the way to a breathable altitude), or to be able to power cycle something to try and fix an issue.
At the end of the day, there are so many other ways for the pilots to down an airliner and kill everyone, they are ultimately the only people you can’t practically have the system distrust. The only thing you can do is the rule to always have two people in the cockpit but it doesn’t always help.
It's more that they have the ability to control the pressurisation manually in case the automatic system fails.
Ultimately the pilots have to be able to turn anything off that might malfunction.
Also even if you (try to) take capabilities away they are by definition quite smart people and could probably figure a way round if they really wanted to.
Pilots have access to virtually all critical systems on board; if they wanted to kill everyone on board, they could simply fly the plane into a mountain. Pressurization is mostly automatically managed, but if it fails, the pilots must be able to manually depressurize before landing.
Because if you have control of the aircraft you already can kill everyone if you wanted. Manual control of cabin pressure could be useful if the pressurization system malfunctioned and needed to be manually overridden.
All vehicles that can be steered have that possibility, even cars: If there is a steering wheel, it is possible to deliberately crash the vehicle. If it is possible to shut down engines, it can also be used for malicious purposes. In other words, there is always the possibility of using everything for malicious purposes.
On the other hand, the ability to shut down a system that has failed can save everyone on board.
There are approximately 40,000,000 flights each year. Almost all occur without incident. In the entire 120-year history of aviation, only a few accidents have resulted from the pilot intentionally crashing the plane.
Most people can’t breathe at high altitudes due to insufficient air pressure. That’s why airplanes are usually pressurized.
If that extra pressure goes away for whatever reason, people are handed oxygen masks and tanks to help them stay alive. What the GP comment says is that the plane may have been depressurized at one point at high altitude. The pilot’s oxygen mask is usually designed to last longer than any of the other passengers’s masks do. So it’s not entirely implausible that the pilot can still guide the plane into controlled descent, while all the other passengers may have already passed out due to lack of oxygen.
> Most people can’t breathe at high altitudes due to insufficient air pressure.
Not most people. Nobody can breath if the altitude is high enough. There are some individual variability in how high is too high. That is of interest if you go mountaineering, but not really in a situation where an aircraft rapidly decompresses at the altitude MH370 was speculated to be flying at.
> Not most people. Nobody can breath if the altitude is high enough.
Read generously, they're talking about with supplemental oxygen. At 35k feet, even with pure oxygen, many people will not be able to breathe and most will not be able to comfortably. (Above 40k feet, supplemental oxygen no longer works--everybody needs pressurised oxygen.)
(Obviously nobody can breathe above the Armstrong limit, but that isn't relevant with a commercial airliner.)
I think I saw a YouTube video of a guy in a chamber simulating what happens. Basically you have less than 30s before you enter a state of delirium in which it doesn't seem important to put your mask on, so then you die.
That's why they tell you in safety briefings to always put your own mask on before helping others.
fwiw, it’s a really good YT channel. Nice equilibrium between an accessible discourse and going into every important detail. And nice illustrations with what I guess is from flight simulator.
You can't really "land" in the Indian Ocean in an airliner. There has (famously) been a successful ditching of an airliner in a river, but I don't think there has ever been a successful ditching in the open ocean. Here's the kind of thing you can expect to happen even in much more favorable sea conditions close to the shore:
I don't know why I thought a controlled landing of a plane on water was generally possible. Maybe because of the pre-safety instructions where it sort of implies (maybe it's just me) that if a plane were to land on water, I could just put on a life vest, get the raft and get off. Looking at that footage and the death toll, feels like a miracle even that many people survived.
That makes me wonder if being able to land a passenger plane on water is ever a factor in its design.
> I don't know why I thought a controlled landing of a plane on water was generally possible.
Because it is possible and foldr is incorrect in stating that it is not possible.
On the video he linked panicked hijackers were fighting with the pilots for the controls. Clearly that is not an ideal scenario for any kind of landing. Even more so for a tricky water landing one. But that is more of a reason to avoid hijackers fighting with the pilots, not proof that ditching is impossible.
Water landings are clearly not the preferred way to land. They are very risky. But they are also not as impossible as that comment makes them out to be. Here is a list of them from wikipedia: https://en.wikipedia.org/wiki/Water_landing
I didn't say that water landings in general are not possible (though they are difficult even under ideal conditions). I said that landing in the open ocean is not really something that has been done successfully in a modern airliner.
The closest example I could find in the list you link was the following. But it ditched a few miles from the coast and had much smaller engines than a typical modern passenger airliner. Also, it was a cargo flight with only the pilots on board, and the captain was seriously injured.
Well that would be exactly right. I think people are confused because of some of the language you're using. Ditching is extremely dangerous and usually results in fatalities, but it's not impossible. There's a checklist for it.
You are correct about the difficulty of ditching in the ocean. See Admiral Cloudberg's description of ditching a DC-9 in the Caribbean during bad weather. There were many survivors.
Very interesting article. Worth noting that the position and size of the engines on the DC-9 would likely be more favorable for ditching than that of most modern airliners. The low and very large underwing engines generate a huge yaw force as soon as they contact the water, and it's very difficult to get both to contact at exactly the same time in a rough sea.
The video there seems to indicate that the hijackers flew that plane into the ocean (unless the commentary is inaccurate) so that is probably not as good a ditching as it could have been if the pilots had been flying… But yes it’s going to be a lot worse than the ditching on the Hudson in any case.
No, the pilot can depressurize the aircraft at high altitude.
In such a case, the emergency oxygen masks for passengers will drop, but those are only rated for 15 to 30 minutes.
After that Oxygen runs out, assuming the pilot maintains cruise altitude above 25000ft, everyone onboard will lose conscious via hypoxia within 1 minute, and be brain dead within 15 minutes.
No one (except the pilot) would be alive to see the plane crash.
Pilot can also re-pressurize the aircraft after 30 minutes, and breathe fine. Pilot oxygen masks are meant to last for at least an hour.
It's more insidious. At high altitude the drop masks don't provide enough pressure to maintain consciousness for their full rated duration. It's expected that pilots will descend very quickly after a depressurization event to at least 14000 or below. If he stayed at high altitude the passengers probably went unconscious quickly.
Yes, for those interested in this scenario, check Helios Airways Flight 522. I think that's what happened with MH370, except that the depressurization was deliberate. Most likely a single pilot stayed alive and functioning in the cockpit, eventually repressurizing the aircraft.
Perhaps the pilot's goal was to hide all the evidence as well as possible, to create a perfect mystery. Then a controlled ditching would make sense, although it kind of failed considering the debris which eventually reached Africa.
We only have a clue where it might be because Zaharie likely powered “the AC bus back up…Unbeknownst to him, the satellite communication unit starts to acknowledge the satellite again. This is his one mistake — but it’s a forgivable one, as hardly any airline pilots knew about this system feature before the disappearance of MH370” [1].
Without that, debris would only hint at somewhere in the Indian Ocean, probably.
If the pilot tried to kill all the passengers to cover his tracks and then killed himself, as many here have commented (which TBH is extremely cruel and insidious), why did he bother trying to land the plane at all? Why not just cut the engine and dump it in the sea? People who commit suicide are the most depressed. They don't care what other people think!
Why of all the possibilities, you choose the most vile one and present it as if you know the facts?
I'm not making any assumptions about the pilot's motives or the final circumstances. I just wondered about the implications of a controlled glide, as the paper suggested. Is there any uncertainty, any margin for error? There certainly is.
No doubt, the question is whether it was a catastrophic crash, a glide down, or an attempted controlled landing; there's no way to land on water without some parts coming off. The brunt of the wreckage has never been found.
Also, if you would get out of the plane, you are then in the middle of the indian ocean with just your life vest and the sharks. You get maybe 3 days, because the water is warm.
And nobody will find you if they don't know where they should be looking. An airplane life vest doesn't have an AIS transponder, only the life rafts/emergency slides do. If those weren't properly deployed, no chance of a vessel finding you. There are reports of shipwreck survivors about ships passing within a few hundred meters of them in calm seas, and failing to see them.