Malaysia Airlines Loses Contact With 777 en Route to Beijing

[brianw999]

The key issue with oxygen levels is not the amount of oxygen in the atmosphere, it's more to do with the partial pressure of the oxygen within the atmosphere being breathed.

Boyles Law states that "each gas in a mixture of gases will exert its own pressure as if the other gases were not there"

At sea level the atmospheric pressure is about 760 mm mercury. Oxygen forms about 21% of atmospheric air with the other gases being Nitrogen at 78%, Carbon Dioxide at 0.04% and the remainder made up of trace gases.

Oxygen at sea level therefore represents approx 160 mm mercury pressure. The human body requires this partial pressure to allow for the efficient transfer of oxygen across the semi-permeable membranes in the lungs into the blood and pass waste gases such as Carbon Dioxide at a partial pressure of 4.0% from the blood into the lungs for subsequent exhalation. This is known as "Exchange of gases of respiration"

At altitude though the partial pressures start to drop as atmospheric air pressure drops. The atmospheric gases are still present in the same %'age proportions but are now dropping to pressure levels where the exchange of gases cannot be sustained. As altitude increases so the partial pressure continues to drop until the body can no longer sustain the exchange of gases and body cells start to die off. The body is now suffering from Anoxia (No oxygen)
The body cells that are most susceptible to anoxia are brain cells. At sea level if the body becomes anoxic irreversible brain death starts to take place in around 8 minutes. Remember...this is at sea level at 1 atmosphere pressure (760 mm mercury)
At 45,000 feet the atmospheric pressure is only approximately 110 mm mercury with the oxygen component forming just 22mm mercury pressure which is far too low to allow for adequate exchange of gases. Oxygen quite simply does not have enough "push" to get into the blood. At this altitude you will be unconscious in around 5 seconds and start to suffer irreversible brain death in around 30 seconds. You will be clinically irreversibly dead in around 4 minutes. The elderly and children will die first with the fitter teens and 20's year olds lasting maybe another minute or so.

It won't matter if the oxygen masks do come down as they.....
a. don't supply oxygen at a high enough pressure.
b. only last for around 12 minutes and
c. rely on a rapid descent to around 12,000 feet where you stand some chance of breathing.
Even then the respiratorily unfit will still probably die. Are you a smoker ? Bye bye then !!

To summarise what a pilot with evil intent needs to do...

1. Start a climb to 45,000 feet.
2. At approximately 20 - 25,000 feet go onto pressurised oxygen via the pilots pressurised mask (which lasts a damned sight longer than passenger oxygen and is delivered at a pressure conducive with the current altitude)
3. Disable cabin oxygen masks.
4. At 45,000 feet depressurise.
5. Wait about 10 minutes then make a leisurely descent to 12,000 feet and repressurise.
6. Fly to wherever the hell you like, 'aint nobody gonna interfere !

[Gabriel]

According to Ny Times, ACARS was shut down first,

Oh the N.Y. Times said it so it has to be true!

This is official information, not just your usual NYT yadayada.

I suggest you (ask you indeed) to have a look at the latest press conference, and tell us what you think:

https://www.youtube.com/watch?v=i4JaA-bMEWA

[Fear_of_Flying]

The key issue with oxygen levels is not the amount of oxygen in the atmosphere, it's more to do with the partial pressure of the oxygen within the atmosphere being breathed.

Boyles Law states that "each gas in a mixture of gases will exert its own pressure as if the other gases were not there"

At sea level the atmospheric pressure is about 760 mm mercury. Oxygen forms about 21% of atmospheric air with the other gases being Nitrogen at 78%, Carbon Dioxide at 0.04% and the remainder made up of trace gases.

Oxygen at sea level therefore represents approx 160 mm mercury pressure. The human body requires this partial pressure to allow for the efficient transfer of oxygen across the semi-permeable membranes in the lungs into the blood and pass waste gases such as Carbon Dioxide at a partial pressure of 4.0% from the blood into the lungs for subsequent exhalation. This is known as "Exchange of gases of respiration"

At altitude though the partial pressures start to drop as atmospheric air pressure drops. The atmospheric gases are still present in the same %'age proportions but are now dropping to pressure levels where the exchange of gases cannot be sustained. As altitude increases so the partial pressure continues to drop until the body can no longer sustain the exchange of gases and body cells start to die off. The body is now suffering from Anoxia (No oxygen)
The body cells that are most susceptible to anoxia are brain cells. At sea level if the body becomes anoxic irreversible brain death starts to take place in around 8 minutes. Remember...this is at sea level at 1 atmosphere pressure (760 mm mercury)
At 45,000 feet the atmospheric pressure is only approximately 110 mm mercury with the oxygen component forming just 22mm mercury pressure which is far too low to allow for adequate exchange of gases. Oxygen quite simply does not have enough "push" to get into the blood. At this altitude you will be unconscious in around 5 seconds and start to suffer irreversible brain death in around 30 seconds. You will be clinically irreversibly dead in around 4 minutes. The elderly and children will die first with the fitter teens and 20's year olds lasting maybe another minute or so.

It won't matter if the oxygen masks do come down as they.....
a. don't supply oxygen at a high enough pressure.
b. only last for around 12 minutes and
c. rely on a rapid descent to around 12,000 feet where you stand some chance of breathing.
Even then the respiratorily unfit will still probably die. Are you a smoker ? Bye bye then !!

To summarise what a pilot with evil intent needs to do...

1. Start a climb to 45,000 feet.
2. At approximately 20 - 25,000 feet go onto pressurised oxygen via the pilots pressurised mask (which lasts a damned sight longer than passenger oxygen and is delivered at a pressure conducive with the current altitude)
3. Disable cabin oxygen masks.
4. At 45,000 feet depressurise.
5. Wait about 10 minutes then make a leisurely descent to 12,000 feet and repressurise.
6. Fly to wherever the hell you like, 'aint nobody gonna interfere !

Thank you, that last summary would certainly fit what may have occurred.

[BoeingBobby]

This is official information, not just your usual NYT yadayada.

I suggest you (ask you indeed) to have a look at the latest press conference, and tell us what you think:

https://www.youtube.com/watch?v=i4JaA-bMEWA

Not sure what you want me to say, this has all been on this thread this afternoon. They either still don't know squat, or they are not telling us.

[Fear_of_Flying]

Media reports

Unless someone on this forum is on the task force analyzing Malaysian military radar data, then your information comes via the media. At that point, it becomes a matter of weighing the validity and feasibility of each source and report. When different sources start corroborating one another, and forming a cohesive picture, we can be more confident that what we're hearing is true. In this case, even "official" statements are dubious, and are often left being the final corroboration of what we had heard days earlier in media reports, but which had previously been denied.

To me, therefore, it makes little sense to bash CNN, the NYT, or what have you as being invalid sources of information, but it makes just as little sense to claim that because it was reported on CNN, it must be accurate information. Evaluating the information we receive is a process, not a true or false test.

Not to mention, we too tend to take things out of context. For example, the reports on lithium batteries that I saw simply stated that the cargo manifest included a significant shipment of lithium batteries and investigators would have to take that into consideration. It was not the mass media's latest pet theory. Besides, at least by the time I read about the batteries, a preponderance of reports, by that same mass media, was pointing to a malevolent take-over.

[Gabriel]

Brian,

I'm taking this to PM because it's getting too technical and I don't want to spoil the thread, but there must be something wrong with what you say.

If not, passengers who fail to put their masks (or even some smokers that do, according to you) after a sudden loss of pressure in the high 30s / low 40s would die, and they don't, and they don't have permanent damage. After the plane reaches a reasonably breathable level say 5 minutes later just wake up and are fully functional.

[BoeingBobby]

Brian,

I'm taking this to PM because it's getting too technical and I don't want to spoil the thread, but there must be something wrong with what you say.

If not, passengers who fail to put their masks (or even some smokers that do, according to you) after a sudden loss of pressure in the high 30s / low 40s would die, and they don't, and they don't have permanent damage. After the plane reaches a reasonably breathable level say 5 minutes later just wake up and are fully functional.

Gabriel, One of the requirements for a transport category aircraft to be able to make an emergency decent from FL to 14000' in 4 minutes. (So much for Avion's theory but I will leave that alone) So if there is a rapid decompression (And I DO NOT THINK THAT IS WHAT HAPPENED HERE), Pull the speed brakes, gear down and down we go at about 8000' a minute.
Can you say weightless for a little bit? Weeeeeeeeeeeeeeeeeeee!!!!!!!!

[Passion for flying]

I am sorry, but I have been away from the forum until now. After digesting the latest news I have to try a few ideas on the forum members.

As the official standpoint is now that MH370 flew away on a different course it would be interesting to know some previously irrelevant data:

Are there any facts available that proves how much fuel was ACTUALLY uploaded in the aircraft's tanks before departure? Obviously the theoretic range of the 777-200 is larger than provided by the required amount of fuel for the flight to Bejing.
I would hope that the tanker company delivering the fuel to the airplane has been audited by now. Early indications alluded that the aircraft's center tank was empty. Maybe it was not? Would this be noticeable on the climb performance?

Has there been any disclosure of the calculated TOW, giving a hint of a heavier than resonable figure. There must be a copy of the signed off paperwork in KL-?
If the 'plane indeed was heavier than declared it must have used more runway to become airborne. Maybe a 777 certified pilot/forum member could give us some figures of the difference-? Are there cameras monitoring the airport? Those could possibly provide useful information.

Has there been any disclosure of the freight loadchart or similar which could provide a hint of a valuable cargo or other such item-?

Those are all items that would provide clues to potential foul play and the whereabouts of 9M-MRO, in one piece or other.

[EconomyClass]

As before, I am leaning to hijack. Malaysia has its own jihadist movement. I believe the had a skirmish with government troops not too long ago. All of Asia has Muslim uprisings. Buddhists are even tormenting Muslims in Myanmar. So our tendency to look for activities in places like Iraq and Chechnya conflicts with the actual daily news. I'm entertaining the idea that someone got friendly enough with a pilot to be invited into the cockpit and then struck when the iron was hot. The entire Umma from Morocco to Indonesia is aflame. It was in Manila that the first conspiracy to hijack planes was hatched in the 90's. There were hijacks before to do things like get Muslim prisoners released. But in Manila they were planning suicide attacks.

[brianw999]

Brian,

I'm taking this to PM because it's getting too technical and I don't want to spoil the thread, but there must be something wrong with what you say.

If not, passengers who fail to put their masks (or even some smokers that do, according to you) after a sudden loss of pressure in the high 30s / low 40s would die, and they don't, and they don't have permanent damage. After the plane reaches a reasonably breathable level say 5 minutes later just wake up and are fully functional.

Under normal circumstances, when pressure is lost the passengers get supplemental oxygen via their masks and the aircraft makes an emergency descent. The combination of supplemental oxygen, descent to a higher atmospheric pressure and the fact that accidental pressure loss is rarely total all combine to give passengers a better chance of survival. All those factors combine to provide an increasing partial pressure. Most aircraft cruise at around 32,000 - 35,000 feet where the atmospheric pressure is almost double that at 45,000 feet.

The scenario I was posing for a hijacking relied on decompression at an extreme altitude and remaining at that altitude. Up there you are firmly wedged in the "coffin corner" of human physiology.

[Peter Kesternich]

As before, I am leaning to hijack. (...)

I think we need to define "hijack" for the sake of this thread.

(...) Malaysia has its own jihadist movement. I believe the had a skirmish with government troops not too long ago. (...)

These days, believing is not good enough. What's your source for the skirmish with government troops? As for jihadist movements, every country has them, including the US and any European country with a muslim population.

The entire Umma from Morocco to Indonesia is aflame. (...)

... or so FOX News says

If the disappearance of MH370 was a terrorist hijack, then where are the demands or the claims of responsibility?

[Fear_of_Flying]

As before, I am leaning to hijack. Malaysia has its own jihadist movement. I believe the had a skirmish with government troops not too long ago. All of Asia has Muslim uprisings. Buddhists are even tormenting Muslims in Myanmar. So our tendency to look for activities in places like Iraq and Chechnya conflicts with the actual daily news. I'm entertaining the idea that someone got friendly enough with a pilot to be invited into the cockpit and then struck when the iron was hot. The entire Umma from Morocco to Indonesia is aflame. It was in Manila that the first conspiracy to hijack planes was hatched in the 90's. There were hijacks before to do things like get Muslim prisoners released. But in Manila they were planning suicide attacks.

And I'm leaning more towards pilot take-over, though that's always been my feeling. The fact that the transponder and the ACARS were turned off prior to the pilot's last radio communication, as we've now learned, gives further credence to that possibility. It means that the takeover was already in progress, yet the pilot did not (apparently) provide any covert signal that something was amiss when signing off with ATC.

The next big breaks we should probably be hoping for are a second satellite signal to narrow the search, or information on crew or passengers that may shed light on intentions/planning/motive.

[MCM]

My only issue with BB's theory - you can't disable the passenger oxygen system that easily.

That doesn't preclude his theory - it just requires longer flight at high altitude until the limit of oxy endurance.

Would also depend if the 777 in question uses a gas bottle system, or the more common chemical generator system.

[TeeVee]

i've gotta take issue with all this "if it were terrorist...they would've claimed it since that what terror is all about..." crap

au contraire! look how crazy everyone is right now. running around scared shitless that "terrorists" had the ability to pull this caper off. hell, even the idea that they could've done this is making people nuts. the very idea that the governments appear not to know what happened is certainly a scary proposition to many.

besides, where is this terrorist rulebook that requires them to claim responsibility?

[guamainiac]

Hypoxia or other source from something mechanical? The casual "nighty nite" instead of a crisp call back on the hand off followed by other erratic behavior such as turning off switches. Perhaps the plane flew on with no one home.