Qantas Manila ATSB Preliminary report out
I find the explanation of the sequence of events perfectly plausible right up until the bit where the cylinder (or bits of it) retraces its steps and exits the aircraft. That's all I'm saying.
Also what rate of airflow would be expected through the hole in the passenger deck created by the top of the bottle and what area of influence would that airflow have on loose items in the surrounding area?
I would expect any fragments of bottle would have been moved by that airflow down through the hole in the passenger deck and then out through the fuselage as the ATSB explains. That is "not rocket science". Also you have to remember that the pressurisation system would have been pumping a lot of air in trying to maintain the selected press diff.
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Unfortunately, in that link the poster lost all credibility for having any analytical skills with his statement
So atmospheric moisture can get into a pressurised cylinder?
Surely, the point of having a minimum pressure limitation is to make sure the pressure never gets down to zero. Then, if the valve is left open, moisture could get inside and cause corrosion.
Internal corrosion could be a possibility, though.
Every aircraft type I've ever flown has had a minimum oxygen pressure below which you should never allow the contents to drop. The reason for that is simply that, at low pressures (say <300psi) moisture then readily gathers inside the bottle and it can then corrode undetected from the inside out
Surely, the point of having a minimum pressure limitation is to make sure the pressure never gets down to zero. Then, if the valve is left open, moisture could get inside and cause corrosion.
Internal corrosion could be a possibility, though.
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We were always told by the company not to let the Oxygen bottles drop to zero because that would then allow the ambient air to enter the bottle which would then require the bottle to be purged...
If there is sufficient pressure left in the bottle it would stop any of the outside moisture laden air to enter when the valve is open and the bottle is in use.I was told that the air used to fill the bottle was medical air and that has no moisture content for the very reason of stopping or helping prevent corrosion inside the bottle.
Jaba....normal ambient air has a high moisture content which is is not the same as the air used in medical O2 bottles....
So this quote makes sense...
If there is sufficient pressure left in the bottle it would stop any of the outside moisture laden air to enter when the valve is open and the bottle is in use.I was told that the air used to fill the bottle was medical air and that has no moisture content for the very reason of stopping or helping prevent corrosion inside the bottle.
Jaba....normal ambient air has a high moisture content which is is not the same as the air used in medical O2 bottles....
So this quote makes sense...
Every aircraft type I've ever flown has had a minimum oxygen pressure below which you should never allow the contents to drop. The reason for that is simply that, at low pressures (say <300psi) moisture then readily gathers inside the bottle and it can then corrode undetected from the inside out
Lowerlobe; it is not air but oxygen used in medical and aviation bottles.
Additionally, the comment does not make sense. Simple physics tells us that with any pressure hgher than atmospheric pressure in the bottle, no outside air or moisture could possibly get in.
I believe the company tells you to not let the bottles below 100PSI. This is because it is enough (being higher than atmospheric pressure) to keep air from entering the bottle.
And i don't see any problem with the idea the bottle was sucked out. Imagine the amount of air rushing through a relatively small hole, i suspect the air velocity would be more than high enough to blow the bottle towards the hole and out into the atmosphere.
The thing i find amazing is how many people love to suspend reality and common sense and indulge in the most ridiculous conspiracy theories!
Additionally, the comment does not make sense. Simple physics tells us that with any pressure hgher than atmospheric pressure in the bottle, no outside air or moisture could possibly get in.
I believe the company tells you to not let the bottles below 100PSI. This is because it is enough (being higher than atmospheric pressure) to keep air from entering the bottle.
And i don't see any problem with the idea the bottle was sucked out. Imagine the amount of air rushing through a relatively small hole, i suspect the air velocity would be more than high enough to blow the bottle towards the hole and out into the atmosphere.
The thing i find amazing is how many people love to suspend reality and common sense and indulge in the most ridiculous conspiracy theories!
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Honestly ..some people can't see the forest for the trees....
...Is that not what i said...
Lowerlobe; it is not air but oxygen used in medical and aviation bottles.
Additionally, the comment does not make sense. Simple physics tells us that with any pressure hgher than atmospheric pressure in the bottle, no outside air or moisture could possibly get in.
I believe the company tells you to not let the bottles below 100PSI. This is because it is enough (being higher than atmospheric pressure) to keep air from entering the bottle.
Additionally, the comment does not make sense. Simple physics tells us that with any pressure hgher than atmospheric pressure in the bottle, no outside air or moisture could possibly get in.
I believe the company tells you to not let the bottles below 100PSI. This is because it is enough (being higher than atmospheric pressure) to keep air from entering the bottle.
With the aircraft at cruise pressure diff, what rate of airflow would be expected through the hole in the fuselage created by the bottom of the bottle and what area of influence would that airflow have?
Lowerlobe...read your own post. Specifically
"the air used to fill the bottle was medical air"
and "the air used in medical O2 bottles"
Before you accuse me of being picky, air and oxygen are quite different. Air is a mix of nitrogen (78%), oxygen (21%) and other gases. It is like saying water is Hydrogen gas...
The quote does not make sense, the quoted poster has picked a random number that shows his lack of understanding of simple physics. There is actually no danger of moisture getting in the cylinder while pressure is above 14.7psi (atmospheric pressure at sea level). The 100 psi recommended as minimum is presumably to allow a buffer, and an easy number to remember for crew.
So no, it is NOT what you said.
"the air used to fill the bottle was medical air"
and "the air used in medical O2 bottles"
Before you accuse me of being picky, air and oxygen are quite different. Air is a mix of nitrogen (78%), oxygen (21%) and other gases. It is like saying water is Hydrogen gas...
The quote does not make sense, the quoted poster has picked a random number that shows his lack of understanding of simple physics. There is actually no danger of moisture getting in the cylinder while pressure is above 14.7psi (atmospheric pressure at sea level). The 100 psi recommended as minimum is presumably to allow a buffer, and an easy number to remember for crew.
So no, it is NOT what you said.
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I still think that Medical O2 being compressed and charged into a bottle will not contain any H20 to begin with so I think at any pressure, 500PSI or 50PSI there is no water present.
I may be very wrong, but until someone can verify this with absolute refernce to something we can all see for ourselves it is most likely to be a myth.
A Chocky Frog to anyone who enlightens us otherwise!
Cheers
J
I may be very wrong, but until someone can verify this with absolute refernce to something we can all see for ourselves it is most likely to be a myth.
A Chocky Frog to anyone who enlightens us otherwise!
Cheers
J
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Medical/Aviation and Welding oxygen - big differences in Water content
Aviation oxygen should be IAW MIL Spec MIL-O-27210. This spec requires the oxygen to have no more than 2 millilitres of water per litre of gas.
CAA and FAA and presumably CASA air safety inspectors always tell aero-medevac operators to replace any medical oxygen bottles found aboard air ambulances with the aviation equivalent. And the medicos continue to carry their normal medical oxygen cylinders.
CAA and FAA and presumably CASA air safety inspectors always tell aero-medevac operators to replace any medical oxygen bottles found aboard air ambulances with the aviation equivalent. And the medicos continue to carry their normal medical oxygen cylinders.
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Speedbirdhouse.....right again and pedantic is an understatement...
Sprite..I suggest you read more carefully....In the last sentence I said...
Sprite...here is a trick quesion.....what do you think I meant by Medical 02 and what is a Pedant?
Jaba...What we are saying is that IF the bottle is allowed to empty or is not filled with Medical 02 ( for sprite's benefit) in the first place or at some stage (by accident) then there might be moisture present in the bottle which we all agree is not a good thing and might be a reason to suspect internal corrosion.
Instead of a chocky frog.....how about a Kit Kat
Sprite..I suggest you read more carefully....In the last sentence I said...
used in medical O2 bottles
Jaba...What we are saying is that IF the bottle is allowed to empty or is not filled with Medical 02 ( for sprite's benefit) in the first place or at some stage (by accident) then there might be moisture present in the bottle which we all agree is not a good thing and might be a reason to suspect internal corrosion.
Instead of a chocky frog.....how about a Kit Kat
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Run out of Kit Kat's...... how about a black Jelly Bean.!
I wonder if that means there will be a black market for sweets with artificial food colourings and preservatives in the UK like there is with chewing gum in Singapore?
