Qantas 744 Depressurisation
Join Date: Jan 2008
Location: UK
Posts: 36
Likes: 0
Received 0 Likes
on
0 Posts
Attn Tweetair post 501
‘What about an oxygen leak from one of the cylinders/pipes?If the leaking oxygen came in contact with grease/oil or anti-corrosive compound would this cause an explosion?’
No. Not unless there is an ignition source or if the temperature is very (inexplicably) high. Forget it. The resulting fire would be spectacular.
No. Not unless there is an ignition source or if the temperature is very (inexplicably) high. Forget it. The resulting fire would be spectacular.
Join Date: Jan 2007
Location: Second star to the right, and straight on 'til morning
Age: 63
Posts: 513
Likes: 0
Received 0 Likes
on
0 Posts
I'm not sure whether or not this is of any relevance, but here is an O2 cylinder explosion video from YouTube; YouTube - O2 CYLINDER EXPLOSION. It doesn't show the explosion happening but explains the consequences which were pretty serious.
Join Date: May 2002
Location: still in bed
Posts: 190
Likes: 0
Received 0 Likes
on
0 Posts
supplementary Oxygen bottles
Boeing is a very safe plane.
go to look where airbus placed the supplementary Oxygen bottles on the A330 ER. on Northwest flights between Narita and Portland...just behind an economy row seats. image if one of these blowout!
go to look where airbus placed the supplementary Oxygen bottles on the A330 ER. on Northwest flights between Narita and Portland...just behind an economy row seats. image if one of these blowout!
Join Date: Feb 2008
Location: England
Posts: 15
Likes: 0
Received 0 Likes
on
0 Posts
As an ex -400 driver I have fought my way through a lot of the 504 posts.
Of these, about 30 contain INFORMED comments about the 400. The rest should keep there comments to something they know about, like their own type, if they have one! ( ie- there doesn't appear to be a cargo door there!).
I wouldn't be at all surprised that there will be an accident report that will tell us the facts.
Happy flying.( to those that do!)
Of these, about 30 contain INFORMED comments about the 400. The rest should keep there comments to something they know about, like their own type, if they have one! ( ie- there doesn't appear to be a cargo door there!).
I wouldn't be at all surprised that there will be an accident report that will tell us the facts.
Happy flying.( to those that do!)
Join Date: Feb 2006
Location: sussex,england
Posts: 16
Likes: 0
Received 0 Likes
on
0 Posts
The cylinders are metal or composite , crew and passenger cylinders are identical in size and you cannot fit composite ones in the cargo roof only in the sidewall...........there is alot of inaccurate speculation on here.......
Join Date: Mar 2001
Location: Wet Coast
Posts: 2,335
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by lomapaseo
You seem to pre-suppose that there is lots of room down there to move arround in and get it (bottle) up to speed.
. I don't know how much distance would be required to generate enough force to penetrate the skin but the video links on here (Mythbusters et al) indicate one going off is definitely not a Good Thing; anywhere. Even less so at 290 in a thin metal tube.
Join Date: Jan 2008
Location: UK
Posts: 36
Likes: 0
Received 0 Likes
on
0 Posts
Attn Planes 49
Newtonian physics, structural engineering principles, gas flow dynamics, materials science &c. are unique to the 74? The likelihood of any incident (other than a bomb) taking place whose causes have no bearing on general aeronautics, plane design and attitudes towards maintenance is extremely slight.
Join Date: Mar 2007
Location: Roguesville, cloud cuckooland
Posts: 1,197
Likes: 0
Received 16 Likes
on
5 Posts
If an oxy bottle has let go, and I believe this to probably be the case considering the damage done, can anyone think of another incident like it? Is it unique in aviation?
Cunning Artificer
Join Date: Jun 2001
Location: The spiritual home of DeHavilland
Age: 76
Posts: 3,127
Likes: 0
Received 0 Likes
on
0 Posts
I still think that an oxygen bottle explosion in that location would result in the blast destroying the floor in the vestibule of No. 2 Door Right, with the top of the bottle coming to rest somewhere in the vestibule area. Compared to the fuselage structure, cabin floors are so flimsy there's no way that the floor will remain intact from a blast that can blow a hole in the fuselage. There's plenty of video of exploding oxygen bottles on You-Tube for those who wish to look, but the question that still won't go away is, in the event of a bottle explosion, what was the initiator? They don't go bang by themselves.
What Kind of Explosion?
It seems to me that there are two possible types of explosion to be considered. One is an explosion powered by combustion of some material and that combustion aided by the presence of a great deal of oxygen. The other is a purely mechanical type of explosion where the tank came apart mechanically. Given that there seems to be no evidence of fire showing in the pictures available to us, are we not dealing with a mechanical, rather than chemical, explosion? If it was a mechanical explosion, what precipitated it? Was it a weakness in the tank caused by either a manufacturing fault, improper installation, maintenance, or corrosion? Or, was it precipitated by some other action such as "explosion" of some of the cargo?
Commenting on a previous post which speculated as to why the O2 bottles are restrained, it should be obvious why all parts of the airplane are restrained.
Commenting on a previous post which speculated as to why the O2 bottles are restrained, it should be obvious why all parts of the airplane are restrained.
Join Date: Nov 2005
Location: Cheshire
Posts: 183
Likes: 0
Received 0 Likes
on
0 Posts
Vertiginous is inaccurate in his assertions. O2 escaping at high pressure even from a slow leak, can create high temps (adiabatic ) The presence of a small amount of oil/grease can cause ignition. (Check BOC warnings for pressurised O2 cylinders. The YouTube slides show the massive heating and damage caused but no flame explosion.
Explosion - rapid expansion of gases at high pressure. Gases do not have to ignite (ball of flame), but if they do, the explosion is worse & things burn. Knock the HP valve off an O2 cylinder laid flat it will not explode (prob) but rocket across the floor. A restrained canister might 'explode'
What if the Quantas oxygen cyl valve had been hit by shifting cargo?
Explosion - rapid expansion of gases at high pressure. Gases do not have to ignite (ball of flame), but if they do, the explosion is worse & things burn. Knock the HP valve off an O2 cylinder laid flat it will not explode (prob) but rocket across the floor. A restrained canister might 'explode'
What if the Quantas oxygen cyl valve had been hit by shifting cargo?
Let's try another tact.
So why did the lower sections all seem to separate along a rivet line, while the rest was random tearing?
That little detail needs to fit in your speculation as well.
So why did the lower sections all seem to separate along a rivet line, while the rest was random tearing?
That little detail needs to fit in your speculation as well.
Join Date: Mar 2008
Location: man
Posts: 48
Likes: 0
Received 0 Likes
on
0 Posts
Can i just ask how the O2 bottles are being joint(two halfs joint from top to bottom or as a cylinder with top and bottom joint)
Are the composite bottles carbonfibre or kevlar???
Are the composite bottles carbonfibre or kevlar???
Join Date: Jul 2006
Location: Australia
Posts: 312
Likes: 0
Received 0 Likes
on
0 Posts
This mornings news indicates that an oxygen bottle is mising which is stowed in the place where the hole is.
Qantas has investigated the complaints from some pax that the system was not working correctly.
Well done captain and crew.
Regards
Col
Qantas has investigated the complaints from some pax that the system was not working correctly.
Well done captain and crew.
Regards
Col
Join Date: Jul 2008
Location: new zealand
Posts: 1
Likes: 0
Received 0 Likes
on
0 Posts
Wing body fairing separation
We have had to replace a Qantas wing to body fairing on one occasion after it was damaged by a catering truck coming down from 2left. They are a custom fit to each airframe no two are extactly alike. The question is whether the fairing left of its own accord or was it pushed? The oxygen bottle loss would probably take place in either event. My guess is the fairing separated aerodynamically and what is shown is secondary damage including the loss of the bottle. As the fairing separated damage to the fuselage at that altitiude was inevitably caused by the differential cabin pressure likely to be 8-6.5psi at crusie alt and the volume of cabin air taking cargo and the bottle out what probably started as a smallest hole enlarging it to what is seen in the photograph. No eveidence of heat
is apparent. The fairing may have been loose or damaged and gone unnoticed.
is apparent. The fairing may have been loose or damaged and gone unnoticed.
Join Date: Jul 2007
Location: My Stringy Brane
Posts: 377
Likes: 0
Received 0 Likes
on
0 Posts
BTNH
Traditional oxygen cylinders are made of steel -- bottom & top caps welded to a segment of tube. Composite cylinders are constructed of filament-wound carbon or aramid fibres over an aluminium liner.
Traditional oxygen cylinders are made of steel -- bottom & top caps welded to a segment of tube. Composite cylinders are constructed of filament-wound carbon or aramid fibres over an aluminium liner.
Resident insomniac
Join Date: Aug 2005
Location: N54 58 34 W02 01 21
Age: 79
Posts: 1,873
Likes: 0
Received 1 Like
on
1 Post
Somewhile back someone stated that it wasn't 'possible' for a (vertically mounted) oxygen cylinder to break loose.
indicates that the 'missing' cylinder was located 120 (cm?) rearwards of STA700 which can be seen on the left of this photograph:-
Has anyone a photograph of a cylinder installation from edge-on (or even 'perspective') without the (sidewall) curtains?
illustrates that there is a bracket fixed to the (curved) sidewall to support the cylinder.
Is it possible (even if not probable) for the oxygen cylinder to fall vertically should the bracket on which it sits break with the result that it falls onto the curved side of the fuselage and sits chafing the external skin weakening the structure (or maybe damages a previous weak patch) which then fails as the pressure outside falls.
In addition, above the 'missing cylinder' location is the door which was claimed to have the 'hole in the floor' (presumably caused by suction during the depressurisation through the hole in the fuselage structure).
indicates that the 'missing' cylinder was located 120 (cm?) rearwards of STA700 which can be seen on the left of this photograph:-
Has anyone a photograph of a cylinder installation from edge-on (or even 'perspective') without the (sidewall) curtains?
illustrates that there is a bracket fixed to the (curved) sidewall to support the cylinder.
Is it possible (even if not probable) for the oxygen cylinder to fall vertically should the bracket on which it sits break with the result that it falls onto the curved side of the fuselage and sits chafing the external skin weakening the structure (or maybe damages a previous weak patch) which then fails as the pressure outside falls.
In addition, above the 'missing cylinder' location is the door which was claimed to have the 'hole in the floor' (presumably caused by suction during the depressurisation through the hole in the fuselage structure).
Last edited by G-CPTN; 28th Jul 2008 at 00:58.
Has anyone a photograph of a cylinder installation from edge-on (or even 'perspective') without the (sidewall) curtains
What I worry about is the possible differences in configuration between the incident aircraft and the pictures.
If the picture is wrong I'll just delete it to avoid confusion.
deleted upon request
Last edited by lomapaseo; 29th Jul 2008 at 18:18.