Qantas 744 Depressurisation
Intruder
Maybe the answer lies somewhere in the Australian CASA's issuance of an AD for "certain oxygen cylinder supports"!
Well here we are several days later and we still don't know the chicken from the egg, but the roost should be getting a lot of attention.
I still enjoy this thread though as long as we can get a confirmed fact and better understanding in a few threads.
I still don't know what the deal is about shards of an Oxygen bottle being found. What does the words "shards" refer? Is this only the valve which could be entirely secondary as it worked it's way out?
I still enjoy this thread though as long as we can get a confirmed fact and better understanding in a few threads.
I still don't know what the deal is about shards of an Oxygen bottle being found. What does the words "shards" refer? Is this only the valve which could be entirely secondary as it worked it's way out?
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The Captain's wife
SLF with no aviation industry involvement
Am I the only one who thinks the Captain's wife's posting on another blog alluded to above doesn't ring very true?
Unless Mrs Bartels is also an airline pilot, he seems to have regaled it all to her in an extraordinary amount of techie detail and moreover she seems to have remembered all the detail (for e.g. it was 50 tons of fuel dumped, it was the R2 door alarm which activated).
So either it was Cpt B himself who wrote this or it's just another wind up.
What do you pro's think?
If it is genuine, can the professionals draw any clues - e.g. positioning of Antiskid warning circuitry relative to oxygen bottles and holes in fuselage etc.
M63
Am I the only one who thinks the Captain's wife's posting on another blog alluded to above doesn't ring very true?
Unless Mrs Bartels is also an airline pilot, he seems to have regaled it all to her in an extraordinary amount of techie detail and moreover she seems to have remembered all the detail (for e.g. it was 50 tons of fuel dumped, it was the R2 door alarm which activated).
So either it was Cpt B himself who wrote this or it's just another wind up.
What do you pro's think?
If it is genuine, can the professionals draw any clues - e.g. positioning of Antiskid warning circuitry relative to oxygen bottles and holes in fuselage etc.
M63
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Well, that is a new one. A repeat inspection for O2 quantity checking? I am not talking about daily/weekly, but more of an out of phase or MEL requirement. A bit iffy that?! I can imagine why though. We were reminiscing last night, as you do?! and I recalled the time when, as an apprentice, we spent all week on a B747, trying to get the pax oxy ring main to stop leaking. It is a big system.
If you were fault finding, you would imagine the fault to be within the cabin or flight deck, because this is the most probable place of a system disturbance. If you use an oxy charging point, as it appears QANTAS do, you would imagine that the last place the leak could be, would be on the bottle. If it had been changed recently, you would check it, but if not, you would be looking at flight deck masks, or passenger O2 PSU's with a bottle of snoop in your hand.
I still can't work out how the bottle let go though. The regulator valve yes, but bits of bottle?
If you were fault finding, you would imagine the fault to be within the cabin or flight deck, because this is the most probable place of a system disturbance. If you use an oxy charging point, as it appears QANTAS do, you would imagine that the last place the leak could be, would be on the bottle. If it had been changed recently, you would check it, but if not, you would be looking at flight deck masks, or passenger O2 PSU's with a bottle of snoop in your hand.
I still can't work out how the bottle let go though. The regulator valve yes, but bits of bottle?
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Incorrect fasterer length
If the incorrect length fastener , ie too long is installed it will only puncture or push off the sealed anchor nut and not rub on any structure and will still secure the fairing and could cause a minor pressure leak.
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Midland63, if you can find any samples of Pilot B's typing from before and see if there are any trends or patterns that are similar to his "wife's", then it's him. In a completely other forum I belong to we busted a con-artist by checking the typing his "wife" was doing on the forum while "she" claimed he was hospitalized.
"all the sentences would just ramble on, there were never any capitol letters, the sentences would always end with commas, never a period,"
Thus we concluded his "wife" had never keyed a single post to the forum while he was "hospitalized". It was him the whole time.
"all the sentences would just ramble on, there were never any capitol letters, the sentences would always end with commas, never a period,"
Thus we concluded his "wife" had never keyed a single post to the forum while he was "hospitalized". It was him the whole time.
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Litebulbs:
If there was a manufacturing defect (such as a wall void) in the bottle (there's mention somewhere in the thread that it was quite new) then it could have required a few cycles to crack and then split. If it propagated the crack to the valve end early enough then the valve could have been ejected quite forcefully as the bottle broke.
However, if it was such a defect, serious questions would need to be asked of the manufacturing and testing process that let it through.
How are these bottles tested, and how often?
I still can't work out how the bottle let go though. The regulator valve yes, but bits of bottle?
However, if it was such a defect, serious questions would need to be asked of the manufacturing and testing process that let it through.
How are these bottles tested, and how often?
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I don't know anything about composite bottles of the size that would be used on a -400. We use a composite bottle for passenger assist, but our crew portable bottles are still cast (iron) alloy. Heavy and robust. Our recharge bottles again are cast and robust. They need to be, when they are being shipped around. They get a fair bashing around.
Again, we were talking last night about O2 bottles. My mate was telling me about a bottle that had a regulator knocked off in a hangar where he was working. It went off like a torpedo, but the bottle stayed intact.
Again, we were talking last night about O2 bottles. My mate was telling me about a bottle that had a regulator knocked off in a hangar where he was working. It went off like a torpedo, but the bottle stayed intact.
Last edited by Litebulbs; 30th Jul 2008 at 00:56.
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"How and how often often are these cylinders tested?
Hydrostatic testing. Test interval per spec in table, i.e. every 3 to 5 years:
CASP H-Test Info
Hydrostatic testing. Test interval per spec in table, i.e. every 3 to 5 years:
CASP H-Test Info
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Fortunately there appear to have been no cabin crew working in that galley at the time
I imagine that all crew when looking at work positions for other flights will now be wondering whether or not it is wise to work in that galley until the answer is found.....
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Anyone know whether any persons on board suffered ruptured ear drums?
Those with blocked eustachin ? tubes will have suffered somewhat..
Oh and what alloy is used to make oxy bottles?
Those with blocked eustachin ? tubes will have suffered somewhat..
Oh and what alloy is used to make oxy bottles?
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Folks.
These last days have seen us deleting dozens of posts in an attempt at keeping threads on track, something most of the professional members here say they want. So please, can we keep to the subject in hand?
Humour mixed in with an informative post is fine but anything else is just the thin end of the wedge leading to conspiracy theories, diving bottles and anything else the MS FlightSim brigade want to throw in.
You can't ask us to keep this forum professional and then instigate the rot by posting nonsense.
Thanks
Duck
These last days have seen us deleting dozens of posts in an attempt at keeping threads on track, something most of the professional members here say they want. So please, can we keep to the subject in hand?
Humour mixed in with an informative post is fine but anything else is just the thin end of the wedge leading to conspiracy theories, diving bottles and anything else the MS FlightSim brigade want to throw in.
You can't ask us to keep this forum professional and then instigate the rot by posting nonsense.
Thanks
Duck
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Great post Vortsa,
Thanks for that.
How is the bottle internal corrosion check accomplished? Bora-scope check? Chinese eyeball? Is the inside straight steel or primer?
So a diligent tech would note a [way out reading] of flat (or say, less than 200psi) pressure on the [individual bottle] and not simply re-service it, but have it removed since it inhaled humid air? Is that right? Schedule it to be re-inspected?
Then corrosion takes how long? A week? This mistake happens every month for six months at out stations and Boom?
Sounds like this aircraft was a "leaker" which is not all that uncommon in my experience.
it couldnt be due to internal corrosion or pitting.... ????.
It would have to be due to two other alternatives
1. incorrectly fitted regulator..... but why fail after 6 months ????
2. over pressure... but how could this occur?
1. incorrectly fitted regulator... for a number of weeks now OJK had been flying around with an mel requirement to physically check oxygen pressure every transit....was it leaking??? possibly
The total pressure of all cylinders is summed to give a single reading in cockpit and a single low pressure would not be indicated there the only way to know if the cylinder was low in pressure is when the physical check is done.
2. If this bottle had shown a history of continually under-reading then it would have been replaced earlier due to the requirement of checking every transit for at least 2 weeks. The question of over pressure would only be acceptable if serviced outside of Australia. The servicing procedure here is to service from one single service point and all bottles are then equal in pressure. The procedure adopted by most overseas MRO's is to remove the low bottle/s and service them in a clean environment, which has its merits... but one of the negatives is you you don't have the uniform pressures, and one or more bottles could be over pressure.
Qantas have a standard procedure which requires those persons servicing oxy bottles to complete appropriate training.. we hope that other agents that work on our aircraft are also trained.
It would have to be due to two other alternatives
1. incorrectly fitted regulator..... but why fail after 6 months ????
2. over pressure... but how could this occur?
1. incorrectly fitted regulator... for a number of weeks now OJK had been flying around with an mel requirement to physically check oxygen pressure every transit....was it leaking??? possibly
The total pressure of all cylinders is summed to give a single reading in cockpit and a single low pressure would not be indicated there the only way to know if the cylinder was low in pressure is when the physical check is done.
2. If this bottle had shown a history of continually under-reading then it would have been replaced earlier due to the requirement of checking every transit for at least 2 weeks. The question of over pressure would only be acceptable if serviced outside of Australia. The servicing procedure here is to service from one single service point and all bottles are then equal in pressure. The procedure adopted by most overseas MRO's is to remove the low bottle/s and service them in a clean environment, which has its merits... but one of the negatives is you you don't have the uniform pressures, and one or more bottles could be over pressure.
Qantas have a standard procedure which requires those persons servicing oxy bottles to complete appropriate training.. we hope that other agents that work on our aircraft are also trained.
How is the bottle internal corrosion check accomplished? Bora-scope check? Chinese eyeball? Is the inside straight steel or primer?
So a diligent tech would note a [way out reading] of flat (or say, less than 200psi) pressure on the [individual bottle] and not simply re-service it, but have it removed since it inhaled humid air? Is that right? Schedule it to be re-inspected?
Then corrosion takes how long? A week? This mistake happens every month for six months at out stations and Boom?
Sounds like this aircraft was a "leaker" which is not all that uncommon in my experience.
Last edited by pacplyer; 29th Jul 2008 at 00:01. Reason: better question
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On the Boeing's that I work on now and for crew O2, not pax, the minimum dispatch is 1300psi, so the bottle or bottles would never get to 200 psi. This would be picked up by the engineers or operating crew prior to departure, unless this baby had a serious problem.
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Yeah bulbs,
That's what I'm talking about; a serious leaker. I've walked onboard and found mechanics engrossed in exactly that: leak isolation that delayed departure. The next station was telexed to watch it when it sat overnight, and a logbook sticker to check pressure was issued.
I've also walked on board a/c that were way low, even though the service check was completed just a few hours prior.....
Mr. Murph says gas can escape. When it is way low what is prudent? Tank exchange?
That's what I'm talking about; a serious leaker. I've walked onboard and found mechanics engrossed in exactly that: leak isolation that delayed departure. The next station was telexed to watch it when it sat overnight, and a logbook sticker to check pressure was issued.
I've also walked on board a/c that were way low, even though the service check was completed just a few hours prior.....
Mr. Murph says gas can escape. When it is way low what is prudent? Tank exchange?