Originally posted by brianw999
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Malaysia Airlines Loses Contact With 777 en Route to Beijing
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Originally posted by HalcyonDays View Post(...) As the prior discussion about Arabic versus Malay showed, I do sense some misunderstànding about the nature of Malaysia as a country and as a society.
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Originally posted by Brainsys View PostAhem is this part of the moderator training programme here? Delete buttons are easier ...
Simply clicking a button just seems to be such an understatement to me.
If it 'ain't broken........ Don't try to mend it !
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Originally posted by brianw999 View PostAnd if that did'nt work ? Have you ever tried to strangle someone ? It's not as easy as the films might suggest.
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Originally posted by guamainiac View PostSo before you bought the farm you'd put yourself out with an axe?
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Originally posted by BoeingBobby View PostI am pretty sure we were talking about what might have been the method used to dispatch the first officer. Or the Captain might have sent him to the back to get some coffee right before he depressurized the aircraft and put them all to sleep!
....Like at 40K you might have a few seconds of consciousness (emphasis on few) to get to some O2, while at 45K you'd have closer to nothing?
...then again, I'm struggling with the physiology...I can hold my breath for 30 seconds- I don't know that the O2 held in my blood is going to switch to unavailable that instantly...
(again, all this is still somewhat moot if he were to lock the door and/or gradually depressurize with the 02 system deactivated.)
My bottom line question is if 45K gives you some meaningful time advantage over high 30's/410/whatever- it can't bee too much but then again 5 sec vs. 1 sec (Or 15 sec vs. 5 sec...whatever) might be worth something to the bad guy...Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.
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Way things are going, we may never get to find out which scenario is actually accurate. Always amazes me that even when it is certain there's no one alive, so many nations, even ones with no involvement jump in with no consideration of cost. At 30 days, it seems the entire would wants to know!!
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Originally posted by 3WE View PostI've been wondering about that 45,000 ft thing from the hair splitting standpoint...
....Like at 40K you might have a few seconds of consciousness (emphasis on few) to get to some O2, while at 45K you'd have closer to nothing?
...then again, I'm struggling with the physiology...I can hold my breath for 30 seconds- I don't know that the O2 held in my blood is going to switch to unavailable that instantly...
(again, all this is still somewhat moot if he were to lock the door and/or gradually depressurize with the 02 system deactivated.)
My bottom line question is if 45K gives you some meaningful time advantage over high 30's/410/whatever- it can't bee too much but then again 5 sec vs. 1 sec (Or 15 sec vs. 5 sec...whatever) might be worth something to the bad guy...
The time of useful conciseness at FL 350 (their assigned and last reported cruise altitude) is 3 - 5 minutes. Yes at FL450 that would be down a couple of more seconds but I really don't think it would matter much. If you knew that the aircraft was depressurizing, and it was not happening too fast you might be able to hold your breath for 30 seconds to a full minute if you are in shape. If he blew it fast or there was an explosive decompression the air would be sucked out of your lungs so fast you would not be able to catch your breath.
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Originally posted by 3WE View Post...then again, I'm struggling with the physiology...I can hold my breath for 30 seconds- I don't know that the O2 held in my blood is going to switch to unavailable that instantly...
Your hart pumps oxygenated blood to the tissues (for example the brain), where the cells use part of the O2 to burn (oxidize) hydrocarbons. The blood also absorbs the resultant CO2 and H2O (byproducts of this oxidation process). This low O2, high CO2 blood returns to the hart where it is pumped to the lungs. In the lungs they pass through a porous membrane. On one side of the membrane we have blood with low O2 and high CO2. On the other side, air with high O2 and low CO2. By a process of difusion (where partial pressures of the different gases tend to equalize at both sides of the membrane) the blood releases CO2 to the air in the lungs and absorbs O2 from it. Then this O2 re-enriched blood goes back to the hart and pumped back to all the body (including the brain). However, only a bit of the O2 in the air in the lungs actually go to the blood, so the air in the lungs still have quite a bit of O2 that can keep you alive and conscious for a couple of minutes without breathing (that's why exhaled air is good for RCP). Not only that, but even if there was no or little air at all in the lungs (for example, if you exhaled all of it as much as you could), the "low O2 blood" still has a good bunch of O2. That's why you can keep alive without breathing for a while (but not as long) even if instead of holding your breath you exhale all that you can.
Now, in the event of a sudden loss of pressure a couple of things happen that make it much worse than holding your breath:
1- As BB said, it's very hard (if possible at all) to "hold your breath" with 1 atm of pressure inside your lungs and nearly 0 outside. The body is not a pressure vessel.
2- If you don't or can't hold your breath, or if you keep breathing, the result is worse than exhaling all that you can under normal pressure: The pressure of the air in the lungs will equalize with that of the ambient air: very very low. The resultant partial pressure of the gases in that air will be reduced proportionally too. So your "low O2 blood" reaching the porous membrane in your lungs will find, at the other side, air with even lower O2 partial pressure, much lower, and instead of gaining O2 it will lose it. A lot of it. Low O2 blood loosing a lot of its remaining O2 before being pumped to your brain. That's a recipe for disaster. It's not that the air in your lungs is not rich in O2. The proportion of O2 will be roughly the same than at sea level. But its density is so low that there is little of everything, including O2 (but also for example CO2, and your blood will be "cleaned" of CO2 better than under normal conditions, but that will not help take more O2 to your brain).
(The credit for this explanation goes to Brian)
--- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
--- Defend what you say with arguments, not by imposing your credentials ---
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Originally posted by BoeingBobby View PostHey Gabriel, I think you missed your calling! You should have been a biology teacher!
I get it that your lungs are suddenly "sucking" O2 out as fast as they can so that the "refreshed" blood is now suddenly O2 lacking...
But I'm still not seeing what happens to the blood that's between the lungs and the brain...that blood was loaded up and sent down the pipe and we know from simple Scuba diving that it isn't going to boil off...
And apologies- I did not mean "hold your breath"...I meant BECAUSE I CAN hold my breath for 30 seconds in constant pressure, doesn't that mean that the "downstream blood" has perhaps 30 seconds worth of O2 stored up...
And thanks for Bobby's reply because when I first heard of the 450 followed by 12-whatever, I could not think of any useful reason to go above the 30's...that's a pretty good sleeping altitude...in fact, perhaps you have side stepped my question...
Is there any plausible reason to go to FL450...any scenario where 5 vs 1 sec might make a difference...and in a "brainstorming" context...I don't THINK there is, but who knows.Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.
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Originally posted by 3WE View PostBut I'm still not seeing what happens to the blood that's between the lungs and the brain...that blood was loaded up and sent down the pipe and we know from simple Scuba diving that it isn't going to boil off...
--- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
--- Defend what you say with arguments, not by imposing your credentials ---
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Originally posted by 3WE View PostOk, to split hairs, it's chemistry, not biology...gas solution dynamics.
Sometimes I think you like to argue with people just to argue. sheesh!
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Originally posted by 3WE View PostIs there any plausible reason to go to FL450...any scenario where 5 vs 1 sec might make a difference...and in a "brainstorming" context...I don't THINK there is, but who knows.
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