Qantas 744 Depressurisation
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The oxy cylinder valve knob is metal with a molded green plastic cover that could have left such a mark.
Thanks for the heads up on the valve.
Rgds.
NSEU
The Reverend
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Machaca,
The picture on #751 would suggest otherwise, i.e. horizontal, if that is the rack of the missing bottle.
-- The missing cylinder resided vertically between stations 800 and 820.
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Hot Dog.. the last pic of post #745 shows the bottle and cabin floor panelling above. Only the tech crew bottles are mounted horizontally (and the other pax ones along the centreline of the cargo ceiling).
If the cargo centreline pax ones let go, they would probably fly sideways, not up/down.
Machaca wins the PPRuNe best technical illustration award
If the cargo centreline pax ones let go, they would probably fly sideways, not up/down.
Machaca wins the PPRuNe best technical illustration award
Cunning Artificer
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I am also reminded that we still don't have a reason for the very large hole in the fuselage, without lesser shrapnel damage holes visible.
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The valve assembly going up and the bottle ejecting down are one plausible explanation for some of the damage signature, but the bottle is mounted vertically between two frames; a section of each of these frames has departed the airframe, what is the failure mode for that to happen?
Note this is just a theoretical possibility which I'm not sure can be entirely discounted yet. Is the composite wing fairing secured to the fuselage otherwise than along its edges, i.e. are there any other tie-rods or other supports affixing it? But if the fasteners are only along its edges, this theory seems to have little merit.
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pacplyer. I can't imagine anyone slapping grease on a control cable that wasn't actually passing through a pulley or fairlead; but who knows. Your point about grease in proximity to an oxygen leak has been made previously but disregarded. I'm not a plumber nor an expert but, many years ago, I had a safety brief in a Naval Armament Depot. Part of that was concerned with Oxygen safety. Having made the point about liquid Oxygen and the formation of LOX Gel from its contact with oil, fat, wax or grease, mention was made of similar hazards from high pressure gaseous Oxygen. Mention was also made of Oxygen in contact with such materials through misuse or leaks. As I remember it, oil and grease could absorb significant amounts of Oxygen, particularly at low temperatures, and form a LOX gel like substance. These substances could be ignited by impact or friction.
What I was told was not in the papers nor on television so could have been complete bowlox; or I could have remembered it wrongly. Anyway, offered for what it's worth.
What I was told was not in the papers nor on television so could have been complete bowlox; or I could have remembered it wrongly. Anyway, offered for what it's worth.
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Great work Mach - but I think I have missed something. ATSB said the O2 bottle is missing - from your EXCELLENT diagram it would appear that the O2 bottle is still inside the fuselage???
As I said, I think I've missed something...
As I said, I think I've missed something...
Grumpy
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If you deleted all of the speculative and stupid contributions to this thread and only left the ones where experts have made a serious discussion of the likely events - you have the ATSB Report.
Well done chaps - and chapeeses.
Well done chaps - and chapeeses.
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.... from your EXCELLENT diagram it would appear that the O2 bottle is still inside the fuselage??? As I said, I think I've missed something...
PS. Top marks Machaca.
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If you deleted all of the speculative and stupid contributions to this thread and only left the ones where experts have made a serious discussion of the likely events - you have the ATSB Report.
I have been an expert in my field for several decades but am still open to ideas from others.
I have experienced the holes in the cheese situation which ensured that I always listened to non experts.
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I'll forgive your rudeness, Forget - I was only trying to qualify what Mach was trying to portray in in the diagram.
Had a CRM eval recently? Damn glad you don't fly on my right.
Had a CRM eval recently? Damn glad you don't fly on my right.
The Reverend
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Machaca, Spanners & NSEU, thank you; I stand corrected. I agree the bottle was vertical in that position but it leaves a lot of unexplained questions still.
I have a total of 18,680 hours operating as a F/E on CV880, B707, L1011, B747-100-200-300 pax and cargo. In 32 years have never encountered a problem with pax or crew oxygen. This incident is a bit of a worry, to say the least.
I have a total of 18,680 hours operating as a F/E on CV880, B707, L1011, B747-100-200-300 pax and cargo. In 32 years have never encountered a problem with pax or crew oxygen. This incident is a bit of a worry, to say the least.
Grumpy
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Beamender99
Get a grip - I am talking about contributors who say things like: 'what IF - the cylinder expolded and generated a fire source - WHAT IF - those that assume O2 explodes. WHAT IF - Qantas is trying cover up a crime - WHAT IF -
The experts - maybe including you but I haven't checked your posts - have kept the discussion within the bounds of physics and not the paranormal.
What sort of expert are you?
I'm one too too. Some years as an aviation safety expert.
Gees !!
Get a grip - I am talking about contributors who say things like: 'what IF - the cylinder expolded and generated a fire source - WHAT IF - those that assume O2 explodes. WHAT IF - Qantas is trying cover up a crime - WHAT IF -
The experts - maybe including you but I haven't checked your posts - have kept the discussion within the bounds of physics and not the paranormal.
What sort of expert are you?
I'm one too too. Some years as an aviation safety expert.
Gees !!
OK guys, I give up...
Quote from forget:
Get a grip Chardy. That's where the bottle was. But I'm sure you knew that.
Merely an occasional browser of this fascinating discussion, I'm finally having to admit to being mildly confused like Chardy is (or was at 0906z Thursday). Still can't find any ATSB reference to the "part of an oxygen cylinder and valve (which) entered the passenger cabin and impacted the number 2 right door frame handle" having been found. So has it?
At risk of provoking public humiliation, could someone briefly enlighten me – and any others labouring under similar ignorance – in a slightly less cryptic fashion than the above?
Get a grip Chardy. That's where the bottle was. But I'm sure you knew that.
Merely an occasional browser of this fascinating discussion, I'm finally having to admit to being mildly confused like Chardy is (or was at 0906z Thursday). Still can't find any ATSB reference to the "part of an oxygen cylinder and valve (which) entered the passenger cabin and impacted the number 2 right door frame handle" having been found. So has it?
At risk of provoking public humiliation, could someone briefly enlighten me – and any others labouring under similar ignorance – in a slightly less cryptic fashion than the above?
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Barkly1992
Gee,
I must have gotten lost. Is this the private pilot expert forum? (That's what is listed on your profile bark old boy (PPL)
I thought it was the Flight Deck section of Rumours and News of the professional pilots Rumour network.
No one said anything about a crime being committed; you wildly exaggerate. If it was unclear, my examples where meant to be strictly hypothetical and in no way imply anything that has happened at Qantas. All my posts are just my own opinion only, and unlike you, I do not profess to be an expert. I am just a reader.
But please tell us, oh great sage of aviation safety, HYPOTHETICALLY what happens when a shipper does not declare lithium batteries in boxes loaded next to leaking oxidizer?
Nothing?
I must have gotten lost. Is this the private pilot expert forum? (That's what is listed on your profile bark old boy (PPL)
I thought it was the Flight Deck section of Rumours and News of the professional pilots Rumour network.
No one said anything about a crime being committed; you wildly exaggerate. If it was unclear, my examples where meant to be strictly hypothetical and in no way imply anything that has happened at Qantas. All my posts are just my own opinion only, and unlike you, I do not profess to be an expert. I am just a reader.
But please tell us, oh great sage of aviation safety, HYPOTHETICALLY what happens when a shipper does not declare lithium batteries in boxes loaded next to leaking oxidizer?
Nothing?
Last edited by pacplyer; 31st Jul 2008 at 12:14.
Machaca,
Excellent photos and visual depiction of possible failure mode.
Just one point for clarity...are you saying that:
1. The oxy valve separated and the valve only was vertically propelled by expanding gases vertically into the cabin.
2. That the main body of the oxy cylinder itself then push hard into its' concave base plate but having nowhere to go, it started to rotate on the base plate
3. That the top of the body of the oxy cylinder with the broken and end then rotated inboard towards the centre of the cargo compartment.
4. That the oxy cylinder was then propelled by expanding gases out through the side of the fuselage.
Excellent photos and visual depiction of possible failure mode.
Just one point for clarity...are you saying that:
1. The oxy valve separated and the valve only was vertically propelled by expanding gases vertically into the cabin.
2. That the main body of the oxy cylinder itself then push hard into its' concave base plate but having nowhere to go, it started to rotate on the base plate
3. That the top of the body of the oxy cylinder with the broken and end then rotated inboard towards the centre of the cargo compartment.
4. That the oxy cylinder was then propelled by expanding gases out through the side of the fuselage.