Qantas 744 Depressurisation

[hetfield]

German online magazine SPIEGEL is quoting an "Expert", "Most probably one of the oxygen cylinders exploded, it doesn't look like corrosion." (My translation).

Loch im Qantas-Jumbo: "Ein solcher Fehler darf nicht passieren" - Reise - SPIEGEL ONLINE - Nachrichten (http://www.spiegel.de/reise/aktuell/0,1518,568216,00.html)

[acmi48]

bbc website tries to be more reasonable -engineers forum ??

BBC NEWS | Asia-Pacific | Engineers 'had fears over plane' (http://news.bbc.co.uk/2/hi/asia-pacific/7526637.stm)

[hardhatter]

:8 speaking from my profession, working for the department of Defense, in the weapons research department, I can say that I am missing one piece of obvious evidence to indicate one reason:

I see no evidence of any shrapnel holes, charring, blackening, blast damage to the baggage and so on.
Even if a pressurised container of some sort ( such as oxygen bottles, aerosol cans etc.) were to fail, it must have left some blast damage and expelled some shrapnel.

AFAIK IMHO it points to either corrosion or puncture of the pressurised skin, to have caused this damage.

But, this just my opinion, based on a few pictures on the telly and on the web. Closer inspection of the damage IRL will show more details. Lets just for the local experts.

cheers.

PS: of course, excellent flying and performance of the crew, hats off! :ok:

[PPRuNe Pop]

The BBC news web page had this gem from one of their knowledgeable writers this morning.

The passengers described hearing a loud bang mid-flight, when the fuselage separated from the plane and caused a rapid decompression of the cabin.


Now that's what I call real stupid uninformed journalism. :ugh:

[whiowhio]

"It is possible that there was some kind of explosive device in the suitcases. There is a hole where there shouldn't be"
...


Flight International Magazine should perhaps consider replacing its Safety Editor?

Whio.

[paulg]

Hmm Jerry B. Now we have a former NASA astronaut confirming existence of UFOs. Any recent sightings in South China Sea? :ugh:

[NSEU]

German online magazine SPIEGEL is quoting an "Expert", "Most probably one of the oxygen cylinders exploded, it doesn't look like corrosion."

Well, there are "experts"... and then there are people who actually know what they are talking about :}

Have a look at the threads after the 744 electrical bus failure a few months ago. Same initial whingeing. "Must have been cheap Asian workers with their staple guns that nearly caused our plane to crash". Whoops, looky here, it was just checked out in Avalon. (Please, don't take my word for it, go and look at the threads yourself.)

I think you need to look back a little further... The rot at Qantas started when the "new world" bosses hacked up Sydney engineering and moved major maintenance to Avalon and sacked a large number of experienced workers. With everything in Sydney, you used to have the international & domestic airports, hangars, stores, overhaul shops, engine lines, technical help offices, etc, all within a few hundred metres of each other.... Now it's a few hundred miles. Need a spare part for an aircraft in Sydney.. no. .sorry.. the part is in Avalon.
Major maintenance (in Sydney) used to be a breeding ground for top engineers... Apprentices and tradesmen had the opportunity to be trained as licenced engineers (c/o the company) and work up through the ranks. Now the same people are probably stuck in dead end/"production line" jobs in Avalon. Morale is probably at an all time low.

[pattern_is_full]

My informed guess: Non-pyrotechnic internal-origination pressure event that blew the cabin skin and then removed the fairing like a champagne cork.

Could be "normal" pressure and a corrosion-weakened skin - or an overpressure source (O2 tank/line, luggage item that popped). Nothing in the pictures yet rules out either, so this must await examination of detailed evidence.

I notice that the Beeb is at last starting to get the msg on "plunge" - a graphic, and an aviation expert's quote, explaining that the descent was standard emergency procedure, now grace their web site.

[whoateallthepies]

Excuse a Rotorheads bloke for posting.
First, congratulations to the crew for an excellent job.

I was intrigued that there is video from "a passenger's mobile phone"? As a member of the SLF community, I thought they should be switched off? Some passenger has survived explosive decompression but ignores the safety brief and decides to risk switching on their phone?! Or am I wrong about this, do Qantas have a "phones OK" policy?

Just wondering

[Blacksheep]

Hmm, all these hats being taken off to the crew for a wonderful job?

Decompression. PNF opens the QRH and begins droning through the SOP that they've rehearsed so often they could do it in their sleep. PF puts the aircraft into the regulation rapid descent, levels out at 10,000' and Bob's yer uncle, time to reprogramme the FMS for diversion to Manila and look up the frequencies. This aircraft was never in any danger of crashing and none of the control systems were affected. The hole isn't even that big, its the missing bit of fibreglass fairing that makes it look more dramatic than it is. :rolleyes:

I know, I know, but its just a Blacksheep doing his customary controversial duty of pointing out an alternative perspective.

Now, time to find out the actual reason why the fuselage burst. As a couple of people have noted, the hole is directly below No. 2 door and the oversized galley just along the side wall there on a QF Longreach 747s. Meanwhile, a very knowledgeable Airframe Technical Services Engineer has pointed out certain evidence of a previous repair in the area concerned.

[Scotsheli]

I'd say based on the very limited evidence available thus far that Mr. Pattern is Full has it about right; some imperfection in that area, possibly long standing, looks to have caused a progressive (and thankfully relatively slowly propagating) pressurization leak, resulting in the failure of the skin and disappearance of the fairing - looks more like a progressive tear through originating from a small source area. Interesting to see the investigation result when it comes out.

Very well done to the crew; trained for it may be, but its always different when you're not 100% sure if there are more little surprises to follow!

[snowfalcon2]

I was intrigued that there is video from "a passenger's mobile phone"? As a member of the SLF community, I thought they should be switched off? Some passenger has survived explosive decompression but ignores the safety brief and decides to risk switching on their phone?! Or am I wrong about this, do Qantas have a "phones OK" policy?

Don't know about Qantas, but many phones have a "flight mode" where the radio is inactive but the camera and other applications can be safely used. Whether that is allowed also during start and landing seems to vary between airlines - some demand all electronic devices to be switched off in those flight phases.

[G-CPTN]

The residue of film-wrap appears visible on the grey 'bag'.
It will have been subject to a lot of airflow from the moment of the depressurisation until landing - that could have damaged the film, rather than something inside the bag which is what I feel you are suggesting.Agreed - I was merely pointing out that there appeared to be film remaining and that indicated that the grey item had originally been wrapped (as suggested as being standard practice for 'loose' items on pallets) and, indeed, that significant 'windflow' would have shredded the film. No suggestion of anything explosive inside the grey 'bag'.

[Capt Kremin]

BlackSheep, as I posted before, this was not a "simple" emergency descent. This crew had many other problems to contend with which shall become known in due course.
Hats off to them.

[Dr Illitout]

The O2 cylinders on the 747-400 I worked on were mounted in the roof of the forward cargo bay, well forward of this area.
The cargo fire bottles were mounted in the side walls also well forward of this area and if my memory serves me right, on the opposite side. The 747 I worked on was not a Qantas a/c but I don't think they are that different.
This fairing is held on by loads of screws of varing lengths. It is possible to put an incorrect length one into the fairing and for the tail of the screw to come into contact with the pressure hull and damage it. Boeing have issued several safety alerts warning of this saying that this could cause a fatigue failure in this area. Maybe??????????????????

Rgds Dr I

[pinkaroo]

Anyone know if this aircraft was at LHR earlier in the week, say Monday? It would be the day the other arriving QF was delayed in BKK for a good few hours.

[Blacksheep]

Simple or complex Capt Kremin, over-dramatisation of airline events does not serve our industry well. As an engineer I prefer to take a more detached view and focus on the real issue, which in this particular incident is why was there a structural failure at that particular part of the fuselage on this particular flight and how shall we ensure that something similar doesn't happen again. That is what is really important here, rather than plunging aeroplanes, crying Cabin Crew and the presence or absence of superhuman heroics at the pointy end.

[nooluv]

"TERROR AS 'HOLED' JET FALLS 20,OOO FEET!"
The headline from the Middlesbrough Evening Gazette...
Must be the best yet.
"Passengers vomited when oxygen masks had to be used".
Thats not a good idea is it?

[theoldbull]

From an "insider" with over 40 years experience on commercial aircraft and 35 working on B747s, please note;- In that area of the fuselage on B747-400s between the right hand cargo lining and the fuselage there are 13 oxygen bottles, the first 7 of which are mounted vertically the remaining 6 are mounted horizontally. It appears that it is possible that one of the horizontal bottles may have let go and with 1750 psi projected itself through the fuselage skin and dislodged the fibreglass wing to body fairing.
Once part of the fibreglass fairing was breached the airflow would make sort work of the entire fairing assy. The location certainly aligns with the oxy cylinders and the damage is consistant with an event as described.

[Mech-prentice]

My new favourite media quote:
"A gush of air hit the plane, ripping a hole in the undercarriage."

Channel Ten (possibly Nine, will check) news anchor.

[Cater]

Funny how all the pictures on the TV show people filming the flight with Moblie Phones Clearly they all had time to get there phones out switch them on and start taking pictures ????

[FlyGooseFly!]

I was travelling SLF in business class on a B.A. 747 way back in 1988 - when suddenly - SHOCK! HORROR! The aircraft dropped like the proverbial stone. All the oxygen masks deploying didn't bother me at all - but the dense white fog and virtually instant cold rush of air had me more than a little concerned as to whether this was a crew controlled matter or gremlins taking over but as I was still alive and the airframe intact I thought there was every prospect I'd live a bit longer. However; the aeroplane seemed to be a glider which was confirmed by several half hearted ignitions which happily for all concerned caught on at the third attempt. I later had a little chat with the 2nd officer - clear air turbulence causing complete flame out - just how low did we get I asked - low enough old chap, low enough !


There was no structural damage in this case and the incident was not reported in the press.

[Pinkman]

It is possible to use a camera on a mobile phone in 'flight safe mode', the pax may not have broken the rules.... this mode just disables RF Tx/Rx so the phone can be left 'switched on'.

Pinkman

[sispanys ria]

I was travelling SLF in business class on a B.A. 747 way back in 1988 - when suddenly - SHOCK! HORROR! The aircraft dropped like the proverbial stone. All the oxygen masks deploying didn't bother me at all - but the dense white fog and virtually instant cold rush of air had me more than a little concerned as to whether this was a crew controlled matter or gremlins taking over but as I was still alive and the airframe intact - clear air turbulence causing complete flame out - just how low did we get I asked - low enough old chap, low enough !
Dense white fog and rush of air following a flame out :bored: ? Sounds like Hollywood movie... how come a lack of pressurization can lead to explosive decompression symptoms ? I experienced engine out and cabin dump at FL280 few years ago and we had quite a reasonable cabin climb rate.

[Rainboe]

I think it is time the Moderators took a bit more control. This thread has run rampart with 100 amateur crash investigators again trolling out all sorts of idiocy. It makes it quite unreadable. why are you leaving garbage like this? How about the plane might have hit something like a mini meteorite? Shooting stars are a reality that can be seen if you are lucky. Why couldn't a plane run into one of these?

PLEASE can we have a bit of silence and just aviation professionals contribute? I actually waded through a lot of the dross here last night and I wish I hadn't- Spotters desperately trying to find if they saw the actual aeroplane at T4 the other day! People with an axe to grind against Qantas about outsourcing all trying to get their bit it. Leave out stupidity, leave out politics, this is an incident review ONLY. I really can't be bothered to wade through keyboard diarrhoea like this- it is making the whole thread unreadable. Professionals are keeping out because of it!

[spinnaker]

Nice work from the crew. I guess some snot nosed investigator come will come along and find something they did wrong in procedure, but in my book, to the crew. :D :D :D

[Torqueman]

I'm with you Old Bull.

Most likely an Oxy bottle letting go.

Looks about the right location.

Though to be certain I'd have to examine it closely which we can not.

So people let's not hang anyone just yet.

The unfortunate thing about all this is how the Qantas management now go into the, 'Damage Recovery/find someone to blame game'.

[Blacksheep]

The horizontal oxygen bottles are mounted at cargo bay ceiling level, above the fire containment linings and about three feet higher than that hole.

[Jerry B.]

Just Google "planes hit by space debris" and you will find out for yourself!!! I wonder who is the idiot here??? A true aviation "professional" would not discount this theory and would not slander the post of another professional!
I am happy to contribute any ideas in the absence of any official findings as are other's on this forum. Maybe, just maybe the investigators will find that something hit the plane, than again maybe it was corrosion, an oxygen bottle, shifting freight etc. etc..

[Phil1980's]

What annoys me is all these people saying it was NOTHING!....No it wasn't to people who were sat in the plane...just because you "know it all" no need to be smug and hate passengers for being worried!

[Hotel Mode]

So this space debris falling from the sky manages to hot the plane not on the top or the front but on the side.. wow. :ugh:

[TWT]

Jerry,

Take another look at the picture.The metal is not folded inwards is it ?

[AMEandPPL]

Funny how all the pictures on the TV show people filming the flight with mobile phones. Clearly they all had time to get THEIR phones out, switch them on and start taking pictures ????

Or did they ? Was that actually specified ? Perhaps these were those digital cameras which take a short period of video - or even a proper video camera ? Nothing illegal about using THEM in flight.

[Teal]

real stupid uninformed journalismAnd more than 24 hours after the incident, the evening news in Australia (Channel 10) is still reporting that the jet was "...seconds from plunging into the ocean..." :ugh:

[Desk Jockey]

Looking at the high detail photo of the breach, is that the head of a golf putter I can see in the lower right of the hole?

It's gold coloured and has a large 'S' engraved on it.
Looks like a NO STEP decal to me.
http://img510.imageshack.us/img510/962/20080726132717hq5.jpg

[Jerry B.]

I did take a look at the pictures. I also read post #273 which got me thinking. Are you curious too???

[Hi_Tech]

In my 38 years as an engineer on Boeing, one thing we have learned is that cracks on structure that is hidden from view from normal inspection fail dramatically. Lap joints on Boeings are a major concern. This Qantas aircraft structure has failed at one such Lap joint, as is clear from the photograph. This area is hidden behind a fuselage fairing that gets opened once in 18 months. Cracks progress over rivet lines and in my aviation carrier I have seen hair line cracks as long as 24 inches and fuselage has not failed like in this incident. So this one must have remained out of sight for a long time. (Remember Aloha 737.)
One has to be patient for the experts to complete their assessment. Jumping to conclusions is amateurish. Some of the posts I have seen are hilarious to say the least.
1. Fuselage fairing failed first!!! It is clear that Fuselage skin popped out with an explosive force. A fiber glass fairing came in the way & it had no chance of holding on. So that was a secondary failure. It will be of ineterst here that when fully pressurised, fuselage skin 1ft x 1ft has a force of half a tonne on it. You can calculate the force on the skin on this failed area.
2. Oxygen bottle exploded!!! There will be a huge fire if that happens. There is no report of that in this case. Again oxygen bottles are not in this area.

The only possible human induced cause in this incident is an explosion of some sort or shifting cargo that made a small damage that resulted in a big failure when aircraft got pressurized fully at high altitude.

[Desk Jockey]

I was on a Trident :E way back when on a pressurisation check.(On ground of course) We were at max diff checking the first safety valve when by esteemed colleague let go of the wrong switch. This resulted in popped ears a dense white fog and the airframe fitter appearing through the fog with the safety valve collar in his hand ready to clout said esteemed person on the bonce. Switch set the other way and popped ears again! (Yes you do get white fog!-and red mist....)

[beamender99]

Longreach - I believe Longreach is the generic name given to all QF 747-400's, just as SIA called their first 747-300's "Big Top ". and their -400's Mega Top. QF delivered their first - 400 non-stop LHR - SYD which is a long reach.
( Sorry if the memory has made a few errors - happy to be corrected


I have always understood that Longreach is the QF generic name, however....

The original marketing name was "Stretched Upper Deck"

Fortunately, very late in the day, this was abandoned.
Fortunately - because someone pointed out that it was a very very very bad idea and they should check out the abreviation SUD in medical terms.

Longreach was later adopted and all the PR speak followed.

[TWT]

Jerry,

It looks like a rupture from the inside out rather than something hitting the aircraft from the outside in (e.g.'space debris' as you suggested) is what I was pointing out

[SpannerTwister]

Looks like a NO STEP decal to me.

Don't think so.....

To me it looks like the "S" is the FIRST letter on the decal or whatever.

Immediately before the "S" I can see white, and before the white, a splodge of green......


SpannerTwister

[Leodis737]

Just a quick footnote. NTSB Press release says: "The aircraft has a 5 foot hole in the cargo area forward of the right wing leading edge and there is also some wing damage." Press Advisory (http://www.ntsb.gov/Pressrel/2008/080725.html)

These two low-res photos are the only ones I could find showing the wing:
Manila, lo squarcio nell'aereo - Galleria - Repubblica.it (http://www.repubblica.it/2006/05/gallerie/esteri/aereo-manila/14.html)
Manila, lo squarcio nell'aereo - Galleria - Repubblica.it (http://www.repubblica.it/2006/05/gallerie/esteri/aereo-manila/8.html)

Not much to see. Maybe it's just a reference to the wing-to-body fairing.

[bubbers44]

How about that dead horse to the left of the putter? What an interesting cargo hold. I'm still betting on corrosion or a hairline fracture causing the failure.

[sispanys ria]

I was on a Trident :E way back when on a pressurisation check.(On ground of course) We were at max diff checking the first safety valve when by esteemed colleague let go of the wrong switch. This resulted in popped ears a dense white fog

On the ground you have much more humidity than at higher levels which is the origin of the fog but I would be very surprised that following a flame out you can experience a sudden rush of air apart from the one that may come out of your pants...:E

[ComJam]

Sensationalistic nonsense from the Telegraph this morning...

Apparently the pilots "fought for control" "managed to right the aircraft but not before it had lost 19000 feet" "bravely avoided the local primary school" (ok i made the last one up but it's about the only thing missing!)

Why is it that when an incident like this occurs it's totally beyond the British press to report it correctly...is a de-pressurisation followed by an emergency descent and landing not exciting enough for them?

Idiots.

[beamender99]

Includes....

"Qantas chief executive Geoff Dixon said he was "horrified" after seeing pictures of the hole and said there was no indication of corrosion.

"Our preliminary checks on this indicate there was no corrosion anywhere near where this hole occurred in the aircraft," he told ABC news in Australia. "We really can't speculate on how this happened or causes, but certainly there's going to be a very thorough investigation."

BBC NEWS | World | Asia-Pacific | Engineers examine plane for clues (http://news.bbc.co.uk/1/hi/world/asia-pacific/7526637.stm)

[Jerry B.]

So meteorites now suddenly know the plane's heading?? Do you think they always come straight from the top and the front? So Mr. Physics Professor, think before posting s@*&id comments.

[paulg]

Where is the golf ball then?;)

[Rainboe]

OK then JerryB, after carrying out an atmospheric re-entry, a Slazenger golf driver with a large 'S' on the end zapped into the freight hold and killed a horse that was in there (according to someone else). After all, it was heading SE and things re-enter from the west! BTW, are you any older than 14?

Shall we leave it to professionals to discuss?

I am intrigued at the relatively low altitude of failure. I can't remember with a -400 when the cabin hits max differential pressure. If it was much less than 8.6psi, then the failure would seem to have occurred rather surprisingly early. It would seem to be very well handled by the crew with very stoic passengers- how nice not to hear about screaming and loud prayers! This is certainly not a very hazardous and 'lucky to be alive'/'miraculous' incident as is being painted, but nevertheless extremley competently handled all around. It is good to see how procedures and professionalism being displayed by the whole crew instills confidence in the passengers and results in a textbook ending. I suspect this incident will be examined in CRM matters.

[Baywatcher]

Engineers investigate stricken Qantas jet
July 26, 2008 - 8:55AM
Source: ABC

A team from the Australian Transport Safety Bureau will arrive in the Philippines today to examine a Qantas plane that made an emergency landing when part of its fuselage blew out.
The Boeing 747 jumbo jet was en route to Melbourne from London when a section of the cargo bay was ripped open.
The pilot made an emergency landing at Manila's Ninoy Aquino international airport, and all 349 passengers were flown to Melbourne this morning.
Attention is now turning to the maintenance record of the 17-year-old plane, amid newspaper reports that a large amount of corrosion was found during a major refurbishment of the aircraft in March.
Qantas is yet to respond to the newspaper reports.
Ian Brokenshire from the Transport Safety Bureau says four investigators will look into the cause of the incident.
"They will start to investigate the damage and investigate the maintenance records and other aspects of the flight, including flight data recorded and cockpit voice recorder," he said.

[Desk Jockey]

Only scary thing is putting the rubber jungle back:sad:

[ExSp33db1rd]

Blacksheep said ... .......Hmm, all these hats being taken off to the crew for a wonderful job? Decompression. PNF opens the QRH and begins droning through the SOP that they've rehearsed so often they could do it in their sleep.............

If you have personally Commanded a Boeing 747 through an unplanned emergency descent, I will accept your snide criticism.

I have. Despite the sleepwalking practice, the adrenalin still flows and the lack of precise knowledge of the cause fuels the anxiety.

The crew are trained to do it in their sleep, that's why they did a good job - what's your gripe about that ?

[RRMerlin]

As a customer for the aviation industry's services rather than being involved and a professional metallurgist specialising in high alloy steels, I have had a life-long interest in accident investigation by the aviation industry and I am in no doubt the probable cause of this structural failure will be found. In the meantime we should be thankful that aircraft design, manufacture and crew training have combined to ensure there were no injuries or fatalities.

However, after hearing the latest news items this evening on the Australian media including statements by Qantas executives; I am concerned with the "spin-doctoring" that appears to be underway.

I had contact with the post-accident investigation of Australia's worst rail disaster at Granville NSW in 1977:

Granville rail disaster - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Granville_railway_disaster)

The cause of the accident may be traced back to maintenance cost-cutting by Phillip Shirley; a British "expert" hired by the State Government to "improve" [i.e. significantly reduce the loss or even make a profit] the NSW railway system. Shirley effectively implemented a "bust and fix" maintenance policy and virtually eliminated scheduled preventative maintenance. It took a period of years before the effects of the cost-cutting on track maintenance became apparent. With an impeccable sense of timing, Shirley left the NSW railways not long before the Granville disaster and benefited from political interference in the subsequent inquiry to restrict the amount of blame placed on the Government for the disaster. The subsequent cost of fixing the neglect cost far more than the "savings" achieved by reducing maintenance.

I have a sense of "deja vue" about Qantas and I earnestly hope this incident will make Qantas management take a long, hard look at their maintenance practices, facilities and obligations. It is an old adage that those who ignore the lessons of history are condemned to repeat them. If I were a Qantas executive, I would not want to be seen as Qantas's "Phillip Shirley" and be a contributor to this airline losing its unique status in the aviation industry. From the perspective of a Qantas shareholder, protection of the company's reputation and standing should be the highest priority of the Board along with the long-term survival of the Company. I have grave reservations whether this is the case at the present time.

[Bushfiva]

Found this on net! pretty scary footage!!

With 10 seconds of effort you could have found it in this thread, too.

[Furriskey]

Call me a cynic, but this kind of statement "Our preliminary checks on this indicate there was no corrosion anywhere near where this hole occurred in the aircraft," he told ABC news in Australia." just makes me think that there was corrosion elsewhere of which Qantas were aware.

[pacplyer]

Hi Tech is spot on, imho.

That fairing is not structural, and the boeing CDL may even allow ferry flights with part of it off, not sure, can't remember.

Oxygen bottles or even fire agent tanks exploding are rare, almost unheard of events in aviation (I've never heard of one in flight.) But not impossible due to the possibility of internal tank corrosion. Usually, if there's a thermal expansion problem they will blow out the green "blowout discs" on the side of the fuselage which is their function. Now, they can go off like a rocket in the hangar if tipped over and the brass works get knocked off.... but that's because they aren't secured to anything and the thrust produced by the escaping gas is accelerating your unrestrained, hole-punching newly commissioned "bottle-rocket." But the ship's on board O2 tanks, however, are secured in on board racks aren't they? So If one decides to go into orbit something else must of dislodged it, or it was not secured properly to start with. Pretty unlikely guys if you ask me.

More likely are possible signs of black corrosion on the green zinc chromate where the rivet heads are (dripping downwards) in the photos. It's a common sight on old airplanes in inaccessible locations. On the other hand, it may be a harmless stain and there's no way to tell without a closer inspection.

What is odd about this, to me, is the possibility we are seeing a ULD steel pallet bottom that has been grossly deformed. Many of these containers are steel on the bottom and fastened aluminum on the sides (or in the case of a pallet, just steel.) They are fairly heavy gage on the bottom and FAR regs require the total weight of each individual one to be stenciled on the side for weight and balance calculations. It's surprising to me that an explosive decompression alone could deform such a tough structure if that's what I'm seeing, but clearly it sucked it through the [aft fire curtain] of the [aft lower] cargo compartment to the location it is in now; complete with what you would expect to see, shipping debris, on top of a pallet.

Corrosion or improper repair are the usual suspects in my mind (Ask JAL in tokyo about that.) How many times have you seen an ice bucket quietly leaking into the floor back in galley cart land? How many times have you seen overventing stains behind the lav drain masts?

Note to self: Quit eating those free blue icicles on the lawn every morning at my house under the SID flightpath! :suspect:

[Litebulbs]

Not an expert on ULD design, so a question. Do they have differential pressure protection. If you have a rapid decompression of the hold, (as part of the complete sealed pressure vessel), how quickly can they disperse their pressure, or could the ULD itself, experience an rapid decompression from a potential weak point, after the initial decompression? OK, it would be a minor event due to its volume, but could it be enough to detach part or all of its wall, allowing the baggage that is clearly seen, time to head toward the fuselage hole?

Or the baggage was just strapped down on a pallet!

[SpannerTwister]

ULD's are not "sealed".

Imagine a (ULD-shaped) box, now remove the front of that box and replace it with a fabric curtain.

Given that (even when it's secured) it's effectively "flapping in the breeze", IMHO, if there was a pressurised container in the ULD that "let go", the excess pressure would firstly blow the front flap around, and secondly rip the front flap off, long before there would be any structural damage to the container.


SpannerTwister

[HotDog]

pacplayerbut clearly it sucked it through the aft pressure bulkhead of the lower forward cargo compartment

There is no lower FWD cargo compartment aft pressure bulkhead on the 747. There is a ziplocked neoprene curtain which reveals the cargo fire bottles and the potable water tanks if you un-zippit. The FWD, AFT and BULK cargo compartments are all within the same pressure vessel as the cabin.

[Blacksheep]

- what's your gripe about that ?Nothing. Why quote out of context? Or did you stop reading at the end of the opening sentence? You may wish to read post 263 as well.

I am simply saying there is too much dramatisation of this incident in which the aircraft was never in any danger of breaking up or control being lost. Yes it is dramatic to the general public, but from a professional point of view there are far more serious incidents every day that don't produce such a wonderful photo opportunity, but where the pilots truly deserve our admiration. These incidents usually pass unnoticed outside the industry, because there are no photo opportunies, no screaming passengers, no plunging out of the sky and no primary schools to be saved from a fiery end.

The crew, clenched buttocks or otherwise, followed procedures and landed the machine. Now, a rather interesting engineering investigation will follow. Heaven knows, we may even see an NPRM followed by an AD!

Meteorites, space junk, exploding oxygen bottles, golf putters and dead horses not withstanding. :rolleyes:

[Litebulbs]

So the bags could just progress toward the hole with the mass flow of air going that way? I was not thinking of the potential decompression of ULD's , just why the bags where were they were. I have also been informed by the other half, about the fabric/plastic flap that covers the opening, so a blond moment from me. Sorry.

[pacplyer]

Litebulbs,

Well I'm hoping a sheet metal mechanic who repairs these things will jump in here and comment. I'm not an expert at anything. Just a has-been. ULD's (Underfloor Loading Devices?) are clanky affairs with poorly fitting thin coke "can" doors on the sides that sometimes blow apart on the ramp just from jet blast and high wind. They have imprecise hinges/curtains etc and are just designed to keep dust off or to keep the customer's contents from shifting. They would just simply blow apart save the frame and the steel bottom which appears as that tin colored "strap" in the photo. (It's amazing to me how golf nuts seem to see putters and golfbags everywhere they go ;))

A pallet buildup however would have plastic, netting, straps etc and may be what we're seeing here. But in the torn open region; under this missing faring area, IIRC is a pneumatics crossover bay and should not have anything like this in here. Thus our deduction that it got there through the aft wall of the cargo compartment, which is what you'd expect to see if the spars and stringers failed as forensically described by the engineers in previous posts.

But I am no expert. The above post is; as all my post are: my opinions only. I could be wrong about everything; I'm old.

pac - out

[pacplyer]

Thanks hotdog,

I realize it's all one pressure vessel, but structurally I'm trying to describe that aft wall/curtain area that loaders sleep against in Manila when it's hot. You're right it's not a pressure bulkhead, I misspoke.

pneumatics bays are unpressurized as are the gear wells, right? So the bulkhead is further aft. So all it had to do was transverse a fire curtain.

(trying to remember from 18 yrs ago and my books are 7000 miles away.)

Good work hotdog.

[Ex Cargo Clown]

Well I'm hoping a sheet metal mechanic who repairs these things will jump in here and comment. I'm not an expert at anything. Just a has-been. ULD's (Underfloor Loading Devices?) are clanky affairs with poorly fitting thin coke "can" doors on the sides that sometimes blow apart on the ramp just from jet blast and high wind. They have imprecise hinges/curtains etc and are just designed to keep dust off or to keep the customer's contents from shifting. They would just simply blow apart save the frame and the steel bottom which appears as that tin colored "strap" in the photo. (It's amazing to me how golf nuts seem to see putters and golfbags everywhere they go )

A pallet buildup however would have plastic, netting, straps etc and may be what we're seeing here. But in the torn open region; under this missing faring area, IIRC is a pneumatics crossover bay and should not have anything like this in here. Thus our deduction that it got there through the aft wall of the cargo compartment, which is what you'd expect to see if the spars and stringers failed as forensically described by the engineers in previous posts.

But I am no expert. The above post is; as all my post are: my opinions only. I could be wrong about everything; I'm old.

pac - out

It's difficult to discern what is actually in the whole but having seen the "blown-up" picture it appears that the black bag is indeed on a pallet, and is netted (looks like it was netted too loosely BTW) whereas the red bags don't appear to be netted at all, so may well have spilled out of a bin.

An aircraft unit won't decompress as it's not pressurised, the front curtain on it is designed to keep the bags/freight in and dry, nothing else. As for a container "blowing apart". I don't think so.

As for freight coming through the aft wall of Compartment 2. I think this aircraft may have had more problems than just the hole in the fuselage if that had happened :ugh:

[Litebulbs]

I was not suggesting ULD's are pressurised, but if it was sealed (which it is not, as has been explained apart from fly away kits which are secure all metal bins with locks, or cooled containers) that in a rapid decompression, it would have the potential to be of a higher pressure than the ambient pressure environment around it, which could lead to a rapid equalisation, through a weak point.

However, if the canvas flap just flaps open, then a non event. Hence my apology.

[Ancient Observer]

Some of the contributions to this thread would have made Douglas Adams proud. Why do some contributors engage hyper-improbability drive before typing in their stuff?

[forget]

Purely as a point of interest - any 747 experts there who could calculate, from the size of the hole and good inflow from operating systems, how fast the cabin would climb. Given an immediate max rate descent what's the highest the cabin got to.

[mono]

I'm with blacksheep here. While the crew were perhaps doing this in anger for the first time, they are trained to do so (an earlier comment from an afronted pilot stated they are trained to do it in their sleep - exactly I say!). As an engineer I am trained to fix airplanes. I don't go patting my self on the back everytime I cure a snag and get the a/c on it's way. Pilots and engineers are not there for when things are going well but for when they go wrong!

Enough thread creep.

What we have here is very interesting from an engineering perspective. It is a failure if the pressure vessel, perhaps originating from a lap joint in what looks like the area of a previous repair. Lap joint scribe lines are a know issue with other Boeing types with (IIRC) at least one example being attributed to manufacture rather than maintenance. Of course the previous maintenance history of the a/c will be checked and I personally wonder what disassembly and prep was required for the initial (scab) repair. There are at least 2 frames missing. Were these replaced at some time and failed at their splices?

Also to further confuse the impact/explosive decompression argument. Some of the structure which has blown outwards does indeed appear to have its outer edges curled inwards!!!!

I await the report with interest>

[lomapaseo]

am intrigued at the relatively low altitude of failure. I can't remember with a -400 when the cabin hits max differential pressure. If it was much less than 8.6psi, then the failure would seem to have occurred rather surprisingly early


That's how oil-canning behaves.

it's a case of residual strength vs buckling. If it was pure over-pressure then your thinking would be correct.

[Phil1980's]

@HotelMode........Well Sir...Aeroplanes have special little things on them that turn the plane and a meteor doing a diagonal fall could hit it :p I wasn't being sarcy that much just being playfull :p But I still agree with the meteor idea aswell as others :)

[FlexibleResponse]

I am just a pilot...but I have been around for a little while...so please accept my comments with that caveat.

I would postulate that the failure started at either, the top or the bottom of the fractured area. That would mean the failure mode was preciptated by either of two completely different causes.

1. If the failure stared at the bottom of the rupture area, it can be seen that the margin of the damage started along the fastener lines. This might possibly be the result of high cycle fatigue and possibly induced by corrosion, poor manufacturing, poor repair or just good old age (high cycle fatigue).

2. If the failure started at the top of the rupture area, then I would start to get a little excited. To my inexperienced view, I can see a panel of metal that seems to show clear deformation from a blunt object trying to escape from inside. There seems to be clear evidence of skin overload and tearing in an area that is not related to (or weakened by) the lines of fasteners. The honeycomb filled wing root fairing in the associated area also seems to have failed in overload and subsequently the aerodynamic forces have caused the failure of the fasteners resulting in detachment of the major portion of the fairing.

My gut feel is with the second suggested mode of failure.

In summary, I am suggesting an overload failure from some mechanical source as opposed to high cycle fatigue emanating from an undetected corrosion induced crack or prior damage.

But, of course this is pure speculation on my part. The investigators will enlighten us in due course with the actual failure mode. I hope this adds to the discussion.

[theoldbull]

Referance to Boeing Illustrated Parts Catalog (IPC) 35-20-00-02-001 clearly shows on Manufacturers Serial Number (MSN) 24806 which is VH-OJK that there should be an oxygen bottle showing through the gap between Station 800 and 820 which is where the hole is. Where is it? Did IT cause the rupture? My money is on the fact that it played a major part in this incident.

By the way Hi Tech post 284 implies that if it was Oxy then there would be burn marks. Oxy only explodes or burns if there is an ignition source. It supports combustion but does NOT burn in itself.

Also note that the brown stains that people on this forum are implying is corrosion is in fact a brown anti corrosion compound (possibly LPS 3 or boeshield) that is sprayed on the rivet lines during maintenance. Corrosion in this area of B747s is very rare.

Over and out till the 'sperts finish their investigation.

[pacplyer]

An aircraft unit won't decompress as it's not pressurised, the front curtain on it is designed to keep the bags/freight in and dry, nothing else. As for a container "blowing apart". I don't think so.

As for freight coming through the aft wall of Compartment 2. I think this aircraft may have had more problems than just the hole in the fuselage if that had happened


Right cargo clown,

I agree with you. By "blow apart", I meant "fall apart." I didn't mean to imply that a ULD is a pressure vessel. It is not. It is a flimsy non-air-tight box with no sides but tin foil doors if it even has that. But it is sitting with higher pressure relative to 30,000 feet as is everything inside the pressure vessel. The differential will instantly suck those flimsy doors off along with whatever was inside. More of an external tornado of air moving from the upper decks towards that hull breech and disrupting anything that gets in the way.

But I'm still surprised to see the bottom of the pallet ripped off the flooring pallet locks, and moved aft if that's what that is.

[jimpy1979uk]

The location of the damage is right where two of the Oxygen cylinders are approximately STA 800-840 ref IPC 35-20-00 and was wondering whether the passengers actually had a supply of oxygen as all the bottles are linked in parallel so when the bottle left the aircraft the system would quickly bleed away. Obviously in the intial part of the incident there was sufficient Oxygen in the system to open all the PSU doors in the cabin, this may explain why some of the passengers were feeling sick as nausea is a symptom of altitude sickness.

[lomapaseo]

There have been some really good posts in the last 24 hours making this thread worthwhile reading. Unfortunately they are still embedded along the 10-90 rule of only 10% good. :)

Some of the best have been from examination of the photos with some experience in either loading and/or maintenance. So to continue I have enhanced some more photos hopefully to match up with some early release factuals from the Australian investigators.

http://fromtheflightdeck.com/MEL/QF-Hole-03.jpg

http://fromtheflightdeck.com/MEL/QF-Hole-04.jpg

[John R]

If anyone has time for a question from SLF, could you tell me approximately what the rate of descent would have been in feet per minute for this type of emergency manoeuvre?

Thanks

[Xeque]

At a guess - 20,000 feet in 10 mins = 2,000 fpm or 8 mins at 2,500 fpm

[compressor stall]

Remember with structural damage, descent is unlikely to be at Vmo...more likely at the speed at which the event occurred.

[pacplyer]

Right, but we used to cruise at .84 econ on the -200's,

So if he threw out the boards and if he threw out the gear (I know, I know: the gear speed is what on the -400 mach at alt? but it can be done) it's gotta be a higher decent rate than that....

Surely....

[AnthonyGA]

Some of the discussion here (and even more so in the media) seems to me like a tremendous dramatization of an incident that harmed no one and simply required an emergency landing. Something made a hole in the aircraft, pressurization was lost, the crew did exactly what it was trained to do, the aircraft behaved exactly as it should, landing was uneventful and nobody was hurt at all. It's almost a non-event. But I guess the hole looks good on TV.

People should be reassured by this, in a way, because even though a hole blew open in the aircraft, it still flew just fine, and everyone got down safely with nothing more than an exciting story to tell the grandkids. All the procedures worked. Nobody was ever in any real danger. That's quite unlike what the fictional Hollywood or mass-media verisons of the story might be. Everything worked by the book and everything went fine. Charleton Heston didn't have to be resurrected to fly the plane, and Joe Patroni could still sleep late.

Some media love having a nice big hole to photograph, although it's difficult to sensationalize it very much without any bodies. Fill the screen with the picture, talk about the "dangerous plunge" as if it were an accident rather than a deliberate and controlled descent, try to find a few passengers emotional enough to put on camera, and lower your voice when you mention that nobody was actually hurt (but be sure to mention the ones who vomit).

The only real concerns here are technical and cannot really be adequately addressed until an investigation is completed. Was this incident linked to the age of the airframe? Was it improper maintenance or operation? Was it simply a freak accident? Ultimately what the industry needs to know is the likelihood that it will happen again: if that likelihood is low, no problem, if it is significant, something will have to be done to reduce it to insignificance. Either way, I don't see anything to worry much about.

Personally I rather like the 747-400, so I hope that it turns out to be something Qantas messed up rather than an issue linked to the age or design of the airframe. Sometimes I get the (highly subjective?) impression that people are trying to find excuses to retire 747s just because they've been on the top of the heap for a couple of decades.

[Ex Cargo Clown]

I agree with you. By "blow apart", I meant "fall apart." I didn't mean to imply that a ULD is a pressure vessel. It is not. It is a flimsy non-air-tight box with no sides but tin foil doors if it even has that. But it is sitting with higher pressure relative to 30,000 feet as is everything inside the pressure vessel. The differential will instantly suck those flimsy doors off along with whatever was inside. More of an external tornado of air moving from the upper decks towards that hull breech and disrupting anything that gets in the way.

But I'm still surprised to see the bottom of the pallet ripped off the flooring pallet locks, and moved aft if that's what that is.

I don't have the ULD Technical Manual to hand, but from my experience of AKEs they are pretty sturdy units (unless you punch a whole in one with a forklift :( )

Far more than "tinfoil". To make one fall apart would need considerably more force than a rapid decompression. As they aren't a pressure vessel, I'm sure an 8psi differential would just blow the curtain open, or more likely push the curtain out to release the pressure far slower than a hull breach would.

As for the pallet jumping the locks. Again, I can't see it, the locks and pallet base are stressed to silly levels for turbulence purposes, something like 6g with a full PMC. I really can't see a decompression getting anywhere near those levels. Now if the pallet weren't locked down properly.......

[forget]

it's gotta be a higher decent rate than that....

Of course it is. We started with a very courteous question from a passenger on Rate of Descent, some 'retired buinessman' in Thailand who knows nothing about it posted an answer, you rightly queried it, I agree with your query - and so it goes on.
:ugh:

[Capt Kremin]

Blacksheep and others. No dramatisation here. I'll say it one last time; this was not a canned simulator depressurisation exercise. (Bang, don mask, initiate descent, checklist, land.)This crew had multiple unrelated system failures to deal with subsequent to the depressurisation. The sort of failures that one may criticise in a simulator exercise as being negative training due to being "too unrealistic". They did a helluva job. Nuff said.

[mattpilot]

A little bit of speed/duct tape and its as good as new :ok:

[Xeque]

Yup.
There's been a 'bang', the cabin has de-pressurised, as Captain you have no idea what caused it or what structural damage the aircraft may have suffered, you know you have x number of minutes of passenger oxygen available to get you down to 12,000 feet or so where the air is breathable.
Rather than stress the airframe with a maximum rate of descent one might slow it down a bit to be on the safe side.

[RatherBeFlying]

Looking at Lomapaseo's enhanced photos, I am led to suspect that: the initial rupture was lower down and abrupt -- that piece seems to be missing sucked baggage plugged the initial hole the upper breach is weakened structure that peeled away in a less abrupt fashion to let the air out.

[Rainboe]

It is getting a bit tiring amateur sleuths venting their opinions on what happened and in what sequence! I am happy to read from someone who knows what they are talking about and is in the industry, but please no more armchair opinions! It is becoming a cacophany of opinions from instant amateur self-appointed accident investigators, and there is just no way of picking out the good information from the absolute dross and tosh! We now have people telling us how airline pilots think having never flown a big jet?

Might I suggest anyone with an opinion on what happened preface their posting with what their expertise is please? It is becoming unreadable! 17 pages of which 15 are dross. The 'I must be first with a possible explanation' brigade have struck even here. Shooting stars......love it! But dross, nevertheless.

[stickyb]

Some of the passenger accounts mentioned a "hole appeared in the floor"

Has there been any confirmation of that, or is it just journo-speak?

[peter we]

There are internal pictures earlier in the thread.

[BelArgUSA]

Hello to everyone -
xxx
Captain 747 "Classic" here - also TRI/TRE with 6100 command hours on type...
Not qualified on 400, but I fly the 200s, and have flown 300s, rather similar.
Not a pilot with Qantas.
xxx
In view of the location of the damage, I first suspected explosion of O2 bottles.
Maybe, or maybe not. Who knows at this stage. Investigations take time.
All baggage were likely inside a container. Yet they appear on the picture...
Or were they loaded as bulk...?
I would say maybe corrosion - toilets probably above that area...
I do not know the QF 400 cabin/toilets location and configuration.
xxx
My airline leased former VH-EBA, an old 238, ex QF. Was a high time airplane.
Low cycle it was as well, and in rather good condition.
QF is above average reputation in maintenance. QF crews are professionals.
xxx
Apparently, the incident happened in cruise at FL 290, initial cruise level.
Maybe the cabin was already at its preprogrammed cabin altitude -
So, the cabin pressure differential would have been still low - 6 Psi... ?
xxx
I do not think that the emergency descent was as spectacular as described.
Such a maneuver is generally flown at about 6,000 feet per minute.
Lesser rate even, 5,000 ft/min if flown using autopilot.
Expediate down to FL 140, then shallow descent to FL 100...
Unlikely also that they got the gear down for a steeper descent.
A "clean configuration" is preferable when structural integrity is questionable.
I am certain the flight crew suspected structural problem. I would have.
We practice emergency descents in simulators every 6 months.
Nothing spectacular as a maneuver. If time left, give a PA to cabin...
Obviously, the "rubber jungle" hanging in the cabin is impressive to SLFs.
xxx
I had a different but somehow "similar" incident long ago, flying a 707-321.
The plexiglas lens cover (landing lights) had blown near the RH wing root.
The airplane flew with slight buffets due to disturbed airflow over elevators.
Possible this crew here, got same buffets during the flight into Manila.
xxx
For the rest - I leave the Pprune experts and press reporters decide.
Retiring in 110 days - Probably one of my last posts.
:D
Happy contrails -

[vee-tail-1]

747 "Classic" flight engineer.
Excellent photo of damage over on Flyer. Certainly looks like a corrosion induced failure of the skin under the wing root fairing.

[Xeque]

Thanks BelArgUSA

You answered John R's question perfectly which, strangely, no-one else did. Too busy pumping up their flame guns I guess.

[cambruzzo]

I am interested in comments from those in the know on the impact if any of a greater air pressure differential had this hole developed say at max altitude. It seems to my uneducated mind that the greater the pressure difference the greater the forces when it let go. Could this have been a total loss in that circumstance?

[nonsense]

Oxygen masks failed: passengers | theage.com.au (http://www.theage.com.au/national/oxygen-masks-failed-passengers-20080726-3lem.html)

The Age newspaper is now reporting that passengers' oxygen masks did not operate correctly and quotes:

"However, a source close to the Civil Aviation Safety Authority said exploding oxygen cylinders were the likely cause of the rupture, and would be the main focus of the investigation, as they were stored in the exact location of the explosion and there were no signs of fire."

[GlueBall]

Airframe corrosion not likely. But conceivable corrosion or failure of one of several oxygen bottles mounted along the sidewall. :ooh:

[lomapaseo]

What if it let go at 39,000 instead?

--------------------------------------------------------------------------------

I am interested in comments from those in the know on the impact if any of a greater air pressure differential had this hole developed say at max altitude. It seems to my uneducated mind that the greater the pressure difference the greater the forces when it let go. Could this have been a total loss in that circumstance?

Too many unknown variables (since we don't know the cause yet). If it's a structural failure in the pressure vessel then the altitude pressure differential is likely not significant to the damage. The most significant mitigation to ruptures under pressure is the rib structure in the airplane that limits the size of the hole.

[Ejector]

Does anyone have a link to this plane spotters forum listed below?



BBC NEWS | Asia-Pacific | Plane hole 'not due to corrosion' (http://news.bbc.co.uk/2/hi/asia-pacific/7526637.stm)

'Fingers crossed'

In an online planespotters' forum in February, participants referred to the detection of "serious corrosion issues" in the 17-year-old Boeing 747-438 Longreach during a maintenance check at Avalon airport in March.

Aviation experts say corrosion could have been enough to have caused the 2.5-3m hole in the fuselage - if even a small section of the plane's aluminium skin was able to break free, the enormous pressures generated at cruising altitude could have done the rest.

[Leodis737]

Rainboe: yet the passengers evidently used oxygen during the descent?

There are some suggestions it failed (at least in parts of the cabin):
Oxygen masks failed: passengers | theage.com.au (http://www.theage.com.au/national/oxygen-masks-failed-passengers-20080726-3lem.html)

Mention of lack of oxygen, some masks not dropping, breathing problems.

[glhcarl]

The Aloha incident was caused by a series of small fatigue cracks that after a period of time joined together to cause the rapid decompression and major structural failure. These fatigue cracks were caused by a voids in the Aloha 737 fuselage lap joints.

If you look at the pictures of the damaged area on the Qantas 747, there is a lap joint running right through the middle of the damaged area. Could a faulty lap joint have caused this failure, I don't know its just a thought.

However, there is an AD that requires all lap joints to be inspected to insure they are sound. But this is done externally using untra-sonic testing and since the area that failed was under the fairing, maybe the area was missed or it was just too much trouble to remove the fairing and do the test?

[xyzzy]

Why is it that when an incident like this occurs it's totally beyond the British press to report it correctly...is a de-pressurisation followed by an emergency descent and landing not exciting enough for them?

Why isn't the safety briefing changed? ``In the event of a loss of cabin pressure, masks will drop from the ceiling. Pull towards you and place the elastic around your head. Fit yours first before helping other people. The plastic bag will not inflate. The plane will then descend to an altitude at which you can breath normally.''

I fly as a passenger regularly, and the closest I've come to ``an event'' was when I was inbound to LHR T4 when the IRA mortars went in. I know, as a hopefully educated passenger, that a fairly rapid descent is a checklist item following depressurisation. Most people don't know that, and they assume that the loss of inflow and/or sudden outflow, plus the masks, has caused the plane to dive uncontrollably, hence all the general purpose hysteria amongst passengers and media.

How hard would the extra sentence in the briefing be? Job done, and the cabin crew will have fewer hysterics to deal with.

[Rainboe]

747 Pilot 18 years
There are some suggestions it failed (at least in parts of the cabin):
Interesting. The finger of blame is starting to point to the bottle, not atmospheric re-entry of golf clubs, or horses wild in the freight hold! Rather than trying to sort out fatigue issues that really require expert examination and testing, I think of more interest is the connection with extraneous factors- in this case oxygen bottles. Individual mask failures are irrelevant, the question is did supply fail to large areas of the cabin?

I think we can do without the sensationalism of yet another aviation 'writer' in the press:
Aviation writer Ben Sandilands said Qantas and its passengers were lucky the disaster happened near an airport. "If it had happened on some other Qantas routes we'd be reporting that they were sending the warships out to pick up the bodies."
More aviation tosh from someone out for a buck! It would just have meant flying for rather a long time at 10,000' to the nearest suitable airport! Even the Pacific has some in those interminable wastes!

[GlueBall]

Rainboe: . . ."Catastrophic bottle failure without ignition?"

You don't need "ignition" for a high pressure bottle to explode. Metal fatigue from corrosion inside the 1600+psi bottle can cause the bottle to violently explode, or corroded pipe fittings can separate with explosive force and puncture the fuselage.

[PC767]

How hard would the extra sentence in the briefing be? Job done, and the cabin crew will have fewer hysterics to deal with

Only for the few punters who listen to a briefing. If they cannot be bothered to understand simple seatbelt instructions then why waste time explaining SOPs.

[ImpairedHearing]

Ejector,

The claim was in the first post in this thread:
QF VH-OJK Corrosion Issues :( — Civil Aviation Forum | Airliners.net (http://www.airliners.net/aviation-forums/general_aviation/read.main/3862862/)

Edit: In advance: In case any toes feel like being stepped on, my sincere apologies for linking to 'that site' :8

[Capot]

hence all the general purpose hysteria amongst passengers and media.Media, yes...The Times of today "20,000 foot plunge after belly ripped off"...etc, usw, ad nauseam.

Passengers, no; evidently no hysteria or panic whatsoever. And lots of mobile footage to prove it. Alarmed, maybe, but who wouldn't be alarmed? Yoiu would have to be pretty stupid or drunk not to be concerned about what was happening, at least for a moment or two, after a loud bang followed by rapid decompression. Flight 103 probably felt much the same to many in the cabin, in the first seconds after the bomb went off. But the trick is suppressing the alarm and appearing calm, and they achieved that very well, it seems.

It's the message that many of us try to get over in various pprune fora; passengers not only pay the crew's wages, they are typically very well-educated in what happens on board an aircraft. They do not deserve the ritual auto-contempt that so many in the industry give them, for example writing without thought ..............general purpose hysteria amongst passengers and media.

[lissyfish]

From the AP one hour ago:

"One person close to the investigation, who was not permitted to speak to the media while the inquiry was under way, said Saturday that “some kind of explosion” might have occurred, because the floor above the cargo hold had been pushed up. Two oxygen bottles that supply the pilots are stored in that area.

Australian investigators, who got their first look inside the plane Saturday, discovered shards of an oxygen bottle throughout the cargo hold and in the floor above, which sits below the cabin, this person said. Officials cautioned that it was too soon to know if the oxygen canister had caused the damage, but theorized that it might have played a role, this person said.

“The dangerous goods manifest is going to be very closely inspected to see if there was anything that might have caused the oxygen bottles to explode,” the person said."

[gas path]

The number of oxy. bottles installed is a customer option! If you opt for the total fit they certainly extend as far aft as sta. 880.
The one or two (customer option!) crew cylinders are mounted horizontally immediately aft of the fwd. cargo door about sta. 700
The bottles are either steel or carbon fibre composite.
Looking at the pictures it certainly appears to have unzipped quite nicely although it does look like there is a section of frame 'gone walkabouts':ooh:
In the lower of the pictures it looks like you can just about see part of the frame bent aft.

[colsie]

My local paper has reported the best comment on this. A passenger is complaining that she saw her bag's hanging out the hole after touch down, and that bags should not be kept in an area where there is a chance of this occurring.:ugh::E:}

[Jamesair]

wasn't there an oxygen bottle explosion on a plane over the Everglades a few years ago? If my memory is correct that cost the lives of everyone on the plane. I think these were being illegally transported from one base to another.

[forget]

Capt Kremin.

.....as I posted before, this was not a "simple" emergency descent. This crew had many other problems to contend with which shall become known in due course.

gas path.

The one or two (customer option!) crew cylinders are mounted horizontally immediately aft of the fwd. cargo door about sta. 700

2 + 2 = ??

[MU3001A]

wasn't there an oxygen bottle explosion on a plane over the Everglades a few years ago? If my memory is correct that cost the lives of everyone on the plane. I think these were being illegally transported from one base to another.

No, that was a consignment of oxygen generators being shipped as cargo, totally different animal.

[Machaca]

http://i337.photobucket.com/albums/n385/motidog/QF30_104051.jpg


http://i337.photobucket.com/albums/n385/motidog/QF30_104023.jpg

[Robert Campbell]

One person close to the investigation, who was not permitted to speak to the media while the inquiry was under way, said Saturday that “some kind of explosion” might have occurred, because the floor above the cargo hold had been pushed up. Two oxygen bottles that supply the pilots are stored in that area.

Australian investigators, who got their first look inside the plane Saturday, discovered shards of an oxygen bottle throughout the cargo hold and in the floor above, which sits below the cabin, this person said. Officials cautioned that it was too soon to know if the oxygen canister had caused the damage, but theorized that it might have played a role, this person said.


The photos on post 358 clearly show a section of fuselage peeled out and up.

Assuming that the O2 tanks are approximately the size or diameter of SCUBA tanks (my assumption), it seems that the bottom part of a tank blew through the fuselage and then tore off the composite wing root fairing.

The weakest part of an O2 or compressed gas tank is at the valve fitting assuming no defect in manufacture.

[fc101]

Xyzzy:

Why isn't the safety briefing changed? ``In the event of a loss of cabin pressure, masks will drop from the ceiling. Pull towards you and place the elastic around your head. Fit yours first before helping other people. The plastic bag will not inflate. The plane will then descend to an altitude at which you can breath normally.''

Due to the possibility of press being on board:

"In the even of a loss of cabin pressure, masks will drop from the ceiling. Pull towards you and place the elastic around your head. Fit yours first before helping other people. The plastic bag will not inflate. The plane will then plummet uncontrollably while the pilot attempts to avoid schools for blind orphans until an altitude at which you can breath normally has been reached."


Serious questions now: if it is an o2 cylinder rupturing (seen a Diving cylinder at around 200bar rupture ... it hurt!*) for some reason then the question is what reasons...what are the conditions like around the cylinders: moisture levels (water ingress similar to Oantas' electrical incident), oil (!!!), hydraulic lines etc? I don't have any good idea about the 747 so could someone (Rainboe?) give us an idea of what can be found in the vicinity of that area.

fc101

*at a distance and it made a mess of the shed where the cylinders were being pressurised - makes me wonder now what they'd have done to my E145...

[Airbubba]

QF has had some conspicuous bad luck with O2 bottles recently, they were filled with Nitrogen on 51 planes a year or so ago. Perhaps just a coincidence, we'll see...

[Dairyground]

Almost 50 years experience as SLF, but no formal training in any aspect of aviation. However, I do have experience of system design in other fields and some exposure to mechanical design.

If I were designing a piping system fed by multiple high-pressure gas bottles, I would expect to connect each bottle through a non-return valve. That way it would be possible to remove a bottle whilst leaving others in place and without depressurising the whole system.

Can anyone advise us whether oxygen gas systems on aircraft in general and on the 744 in particular have such fittings? If they do, that could explain why one bottle could escape without the emergency oxygen system failing completely.

If a free-flying oxygen cylinder turns out to have contributed to this event, can we expect to see AD to move all such potential missile outside the pressure vessel?

[gearhorn]

Jamesair,

I believe the Florida crash was the result of improperly packed emergency oxygen generators (not bottles) that caused a raging fire after one or two were bumped and accidently triggered.

I thought that most if not all drop down oxygen came from OG's but, maybe not.

gh

[Blacksheep]

Oxygen systems are designed in the way you suggest Dairyground. The bottles are lifed and also subjected to regular inspections, being removed from the aircraft and subjected to non-destructive examination and proof testing. It would be very unusual for a bottle to "explode" in service, though it is not completely unknown. As one poster has revealed, the QF "Longreach" configuration includes a customer selectable option for supplementary oxygen bottles. These would be to permit operation on routes where terrain prevents the aircraft from immediately descending to 10,000 feet in the event of de-pressurisation. It seems that this option installs supplementary oxygen bottles mounted in the location where the hull rupture occured.

Placed under deliberate pressure, a poster whom I presume to be a QF management pilot has revealed that the event was not as routine as first appears (such incidents seldom proceed exactly as rehearsed in the simulator) and that the crew had additional un-stated system problems to handle. Perhaps an oxygen system problem is included among these?

[sevenstrokeroll]

oxygen bottles as suspect were mentioned as early as post 22 and 61...

one must ask, if the bottles that supplied that pilots were both ruptured, what the outcome of the flight might have been

can you imagine some poorly paid baggage handler accidently bumping a bottle and having it come apart later that day?

glad they are down safely.

[Rainboe]

The bottles are a major maintenance item only. I don't remember any hatch or access to that part of the aeroplane. The bottles occupy a small space between the central wing carry through box and the rear of the hold. You obviously want as much hold space as possible, so the rear of the hold will come down as close as possible to the wing box. The bottles are quite large. I do not think aircon plumbing comes through here- I think it goes under the wing box- the engineers here will know. I have checked my Pilot Technical Manual, but these are not pilot accessible areas so the manual gives scant information. The bottles feed into a universal cabin ring main, so there would be NRVs at each bottle as well as pressure reducing valves, and a big stopcock on each bottle. Can any divr say what happens if all the gubbins on the end of an Oxygen cylinder blows off suddenly? Or the end blows off? What happens to the bottle?

It did occur to me that the TWA accident began in this general location, but I am quite sure that the investigators would have discovered if a similar cause could be involved. But the bottles are very close to the wing box which is the largest fuel tank on the aeroplane.

[Leodis737]

It is beginning to look like a discussion about oxygen bottles vs oxygen generators could be coming up soon :hmm:

[Phil1980's]

If the Oxygen blew up for the pilots...then how did the pilots breather from the oxygen when the plane de-pressurised?

[Smilin_Ed]

1. I'm not a 747 mechanic.
2. I am an industrial engineer and a retired military pilot.
3. I would expect that, due to their weight, oxygen bottles would be well restrained simply to ensure that they don't bounce around due to in flight G loadings. A unrestrained bottle which lost its top end, valves, etc., would, of course take off like a rocket, but I can't imagine a bottle properly installed in the aircraft would do anything but sit there and vent its contents. On the other hand, wherever the top end was pointed when it came off, it would knock quite a hole in anything it hit (like the pressure hull).

[lomapaseo]

It did occur to me that the TWA accident began in this general location, but I am quite sure that the investigators would have discovered if a similar cause could be involved. But the bottles are very close to the wing box which is the largest fuel tank on the aeroplane.

It was the water bottles that were located there and attracted some attention since it was reported that repairs had to be performed in this area quite some time prior to the accident due to a ruptured water bottle having disrupted the flooring and wiring.

[CHINOOKER]

with regard to the theory that an oxygen bottle failed of it's own accord,well i'm fairly sure that they are pressure tested at manufacture to about 2-3x operating pressure so a bottle failing on it's own would be quite a rare event!
Having personally carried and fitted these to many BA 747/777 aircraft over the past 30 years,i have never known one to "let go" as it were!.
Personally i do not know the Qantas set up on the 400s,so it is possible that there are extra bottles fitted near to the damaged area,which i am led to believe has a galley unit directly above it.
Personally i would go for the following scenario.....Oxygen bottle fitted in position but has for some reason developed a small leak,(insecure fittings/seal failure etc),....contaminant from galley above finds it's way to bottle and "explosion" occurs!!

[PAXboy]

Pax speaking
slats11and we all know Boeing builds em Tonka tough.
I then asked:
Boeing certainly did build them tough 30 years ago. But - do they build them as tough now...?
787FOCAL replied yes. 747 skins, etc are still the same

I understand that 747s are built the same way, due to design spec, but what is the spec of the 787?


Some of the passenger accounts mentioned a "hole appeared in the floor". It is possible that the 2R door (I think it was) was partially unseated by the failure below it. To those inside, the movement of the door would appear to be the primary fauly as it was the only one that they could see. Whereas, it may well have been a secondary failure.

As to pax experiencing nausea - this may have been to do with the oxygen (lack or use of) but also sheer nerves as they had no means of knowing how serious it was and fearing for their life.

One bit of GOOD REPORTING is in the UK paper The Independent. Simon Calder points out that all went according to plan and that you are still safe in the airplane than on the roads. He says:
No other industry is so tightly regulated, nor staffed with such safety-conscious people, as aviation. Life in the danger zone? Take a spin on the M1. But to prolong your life expectancy, take off.
Simon Calder: You're still safer up there than down here - Simon Calder, Travel - The Independent (http://www.independent.co.uk/travel/simon-calder/simon-calder-youre-still-safer-up-there-than-down-here-877791.html)

[Lone_Ranger]

hello, im just a passenger enthusiast with an engineering background earlier in this thread someone pointed out a small area where the skin appears to be folded inwards as if an external impact event initiated the failure,or was at least present, this seems to have been largely passed by in subsequent posts...seems very significant to me

[Litebulbs]

Speculation alert - please read no further if facts are required -

Looking at the pictures in #358, it seems that the luggage visible is of two colours, greeny/black and red. There is no visibly obvious remains of a ULD, but something that looks like a pallet. I have seen stuff bagged up like this when I was on a flight bringing a rescue party back from Bam, after the earthquake a few years back. The equipment was not pallet loaded, but there was some pretty high tech stuff included. No problem with this but again, you would have thought that oxygen generators should be safe to transport, if all precautions were followed.

Now if it turns out that it was exhibition or expedition kit, all sorts of items could be on the pallet. All individually safe and manifested, but who knows?

Speculation over - In the second picture of #358, on the left hand side of the hole, I believe you can see what looks like an O2 bottle. I have had the privilege to hump these things off and on B74's in the past, so I have been up close and personal with them, so I believe that I am at least qualified to suggest that it could be a bottle.

I await a flame!!

[Yorky Towers]

The experts above, are all to busy coming up with the answer......Give it time for the investigators to have their say.!:D

[sevenstrokeroll]

a times online article indicated that the pilots had trouble with their oxygen supply...and that there was a secondary supply

I would like details on that from a 747 guy.

while I can imagine a "walk around bottle" being part of the cockpit stuff, I'd just like to know.

[ExSp33db1rd]

Quote:
- what's your gripe about that ?

Blacksheep # 306..... read #297 and # 329, maybe you didn't mean it that way, but I'm not alone in interpreting your remarks as a snide sideswipe at the crew - uncalled for.

I agree that the whole thing has been over-dramatised, but what's new in that, regrettable or not ? Many years ago "Roger Bacon", the satirical columnist of "Flight" , threatened to load an aircraft with explosive and ignite it over the Farnborough Air Show so that 100,000 "experts" could categorically state that the aircraft was on fire in the air ! Nothing's changed since then. ( Nb "X" is an unknown quantity, and a spurt is a drip under pressure )

Time we all shut up until some facts emerge.

[arcniz]

Idle speculation:

Litebulbs comment about the O2 cylinder visible in post 358 pix #2 looks right to the eyeball. From the same pix, the white harness dimly seen just forward of the green object looks as though it might be a collection of four to six white tubes for carrying O2 toward the cabin.

If another O2 cylinder were located just forward of the green shape in the pic, then its lower end might line up rather neatly with the bottom of the visible hole, and its upper end with the tongue of pressure hull skin bent outward at top of the damage area. A pressure cylinder failure originating near the base of the inside surface would provide rocket power to propel much of the disintegrating cylinder outward and upward in a manner consistent with the observed hole.

How would a high-test cylinder suddenly decide to disassemble in this manner? Perhaps the very same cargo pallet visible in the post-incident pictures included a rock or ice-climbing pick - with a very sharp, hard steel point (or something similar..hard, pointy) and some still unexplained shift of the cargo bulk brought this chisel point in contact with the pressurized O2 cylinder, allowing vibration to hammer away at the surface and eventually causing a stress failure at the lower inside-facing part of the gas container - with results as now may be seen.

[Machaca]

Example of pallet used on lower decks:

http://i337.photobucket.com/albums/n385/motidog/PAGpallet.jpg

[vortsa]

IT WAS NOT AN OXYGEN BOTTLE EXPLOSION.

2 ways an oxygen bottle explodes:-

1. The head fitting (regulator) blows off. In this incident the bottle would take-off like a rocket, and because its orientation onboard the aircraft was in a vertical position then it would have left a big hole in the bottom of the fuselage. And yes they are adequately secured and have over-pressure relief valves and check valves and thermal relief and every other protection device you could think off . So this did not happen.

2. A breach in the wall of the cylinder, very unlikely but lets say for the argument this did happen. This would be equivalent in force to an explosion as large a bomb going off, and depending on the direction of the blast possible shrapnel damage. If blast direction was inside then expect to see the cabin floor being lifted. If the blast direction was outboard then expect to see more damage and not radiating from a small point in the middle of the hole in fuselage.

Oxygen bottles just don't explode like this, if it was contamination from galley waste that triggered the explosion combining with small leak from cylinder then again the regulator is where that would have occurred.

Yes there is at least one bottle missing but only because the structure supporting it has disappeared.

THINK AGAIN.

[taotoo]

Firstly, I have no aviation knowledge.

Maybe I've misread the thread, but I haven't seen reference to what looks like (original photo) a section of the fuselage wall below the black bags, inside the plane, and reversed.

At the bottom, and in the middle of this section, could there be the top of an oxygen bottle + regulator?

[paulg]

According to an article on theage.com.au site

‘a source close to the Civil Aviation Safety Authority said exploding oxygen cylinders were the likely cause of the rupture, and would be the main focus of the investigation, as they were stored in the exact location of the explosion and there were no signs of fire.’

Bottles do not explode spontaneously. They vent if over pressure.

[wing surfer]

the fire bottles for the cargo area around frame 830, (i believe). They are located on the Right hand side within the area of the hull breach, A good source has confirmed that these fire bottle expiry dates are being looked at as well as the last time they were inspected.

[Sleeping Freight Dog]

Looking at the high resolution photos, the red bags appear to me to
be containing rope. This would seem to be again to me that they
are bags containing nets for new pallets/ULDS. When you ship a stack
of pallets, you must have nets for them as well. I know after the
Arrow DC8 accident in MIA, the regulations were upgraded to state that
all nets had to be secured to the pallets in some way. But, when ULDS
are new, the nets have not been attached yet, they are loaded in
sacks and stowed on the pallets for shipment. Or does any one remember
having to get a new net for replacement? You had to open a sack, sometimes red, to get the new net. Could it be these were loaded on a
stack of empty pallets, said pallets shifted and the shifted pallets
hit an o2 bottle behind the interior fairing? By hitting the bottle, I mean
knocked the stem off.

[Vertiginous]

I have a vivid memory of a widely-reproduced photograph of the TWA aircraft on the ground. It landed on its starboard side — curious in itself. Accident investigators would have had a bit of a job to get at the area fwd of the (absent) stbd wing. Conclusive proof of foul play would have been chemical residues from explosives in the hold and around any breach in it; but perhaps they just found evidence of a substantial fire? Were unfiltered enquiry findings ever released?

[paulg]

Yes Sleeping Freight Dog. If a bottle was involved then something else has happened first to damage the bottle.

[peter mcgrath]

If I were designing a piping system fed by multiple high-pressure gas bottles, I would expect to connect each bottle through a non-return valve. That way it would be possible to remove a bottle whilst leaving others in place and without depressurising the whole system.

Can anyone advise us whether oxygen gas systems on aircraft in general and on the 744 in particular have such fittings? If they do, that could explain why one bottle could escape without the emergency oxygen system failing completely.

Very interesting statement, if the valve was situated on/near the bottle and it and its associating piping was damaged then there would be no air at all as it would all leak out.

There was a report in the age that passengers complained on no air...

[shawk]

I believe that Boeing is aware of the potential damage from leaking oxygen bottles and other pressurized sources in the 747 cargo hold.
The 747-8 has a new and interesting pressure relief valve to prevent this sort of damage.
Presumably, Boeing will offer this valve for retrofit.

[wing surfer]

Looking at the pictures and the way the metal has folded, it would appear that the initial fracture of the hull may have come from around the manufacture join.

The metal around this area looks like it has been folded into the airflow before the wing to body panel disappeared the other damage like it has happened after the fact and it has peeled back with the air flow.


something to think about

[Devcon4]

"QF has had some conspicuous bad luck with O2 bottles recently, they were filled with Nitrogen on 51 planes a year or so ago. Perhaps just a coincidence, we'll see..."


Hi there Airbubba,
It was actually only 1 aircraft that had the Nitrogen in the oxy system. Just thought I would clear that up for all.

PS I am a QF LAME.
Devcon

[NSEU]

The 744 passenger oxygen bottles feed into a common manifold. Each bottle has a pressure relief valve (or rather, frangible disc) which allows the bottles' contents to discharge overboard if the internal pressure is too high. The pressure required to activate this relief valve is significantly higher than the typical system pressure (1800psi), but presumably far lower than the pressure required to rupture a serviceable bottle :}

To change a pax bottle on a Qantas 744, you have to close all the other bottles, both in the right hand (Fwd) cargo sidewall and in the (Fwd) cargo ceiling.

Unless I have overlooked something obvious, if one of the bottles ruptured, I would say that the contents of the entire system would start venting. Question to experts: Do the pressure reducers shown in the Boeing Schematics (35-11-00) have inbuilt check valves?

On this type of pax oxygen system, the bottles feed 3 flow-control units. These allow the oxygen to get to the passengers (after being activated by various manual and automatic methods). The oxygen masks drop from the overhead panels via doors which are unlatched by the oxygen pressure surge coming down the lines. Clearly in the videos, the masks have dropped. Ergo... at least some pressure was present. See other PPRuNe message threads for interesting information on the effectiveness of pax oxygen systems. Once the door has released and the mask has dropped, the passenger has to physically pull down on the mask (to allow oxygen to flow from the overhead unit)

I wonder how many of the passengers remembered to pull down on the oxygen masks after paying careful attention to the preflight safety demonstration? There is, of course, automatic announcements during a decompression to remind them ;)

Rgds.
NSEU

[Machaca]

Sleeping Freight Dog -- a closer look shows no bottle under the earlier spotted (Broadreach & Leodis737) frame section that ended up inside and turned around:

http://i337.photobucket.com/albums/n385/motidog/QF30_816.jpg

[Kentot Besar]

This from The Star :

MAS denies Qantas senior pilot’s claims

By LESTER KONG


PETALING JAYA: Malaysia Airlines has refuted a Qantas pilot's allegation that maintenance of the Qantas Boeing 747 that suffered a ruptured fuselage on Friday had been outsourced to Malaysia, as being baseless.
The Australian-based airline has also confirmed the claim to be untrue.
MAS senior general manager Mohd Roslan Ismail in a statement yesterday said that MAS only handled the engineering and maintenance of Qantas’ Boeing 737 aircraft and not the 747.
He added that MAS’ engineering and maintenance division held an excellent track record.
“The increasing number of foreign airlines who outsource their aircraft to us is a testimony to our success in this field,” he said, adding that third party contracts comprise 40% of their business.
In a press conference in Sydney, Qantas head of engineering David Cox said all of the plane's servicing was undertaken in Australia.
An unnamed senior Qantas pilot yesterday told The Daily Telegraph, a Sydney tabloid, that a mid-air calamity on Qantas flight QF30 from London to Melbourne could have been caused by the airline’s outsourcing of maintenance to Malaysia.
A rupture on the fuselage of the 17-year-old aircraft occurred while flying at 8,839m over the South China Sea from a Hong Kong stopover and forced the pilot to perform an emergency landing in Manila at 11am.
None of the 346 passengers and 19 crew were hurt in the emergency landing.
A sheet of metal was torn from the front of the right wing. The plane had received a new interior at Victoria’s Avalon airport in March.



Wow, big claims from a skygod............the QF engineers will be real happy if it's true; no more outsourcing to MAS, SQ and China. So the recent strike for more $s gets a helping hand here!

[pacplyer]

In the second picture of #358, on the left hand side of the hole, I believe you can see what looks like an O2 bottle. I have had the privilege to hump these things off and on B74's in the past, so I have been up close and personal with them, so I believe that I am at least qualified to suggest that it could be a bottle.

I await a flame!!

Litebulbs,

No flame, how about an attaboy? Good eyeball, good recall.

It looks like a white cylinder all right in that picture at the bottom. I used to have some like that in my hangar. Did you ever notice: did they have red base primer underneth the top coat of white bottle coating? I see red scratch marks on the side.

Does this look like a composite bottle in the picture to you? The end doesn't look like metal to me at least.

"Vortsa" said:
IT WAS NOT AN OXYGEN BOTTLE EXPLOSION.

2 ways an oxygen bottle explodes:-

1. The head fitting (regulator) blows off. In this incident the bottle would take-off like a rocket, and because its orientation onboard the aircraft was in a vertical position then it would have left a big hole in the bottom of the fuselage. And yes they are adequately secured and have over-pressure relief valves and check valves and thermal relief and every other protection device you could think off . So this did not happen.

2. A breach in the wall of the cylinder, very unlikely but lets say for the argument this did happen. This would be equivalent in force to an explosion as large a bomb going off, and depending on the direction of the blast possible shrapnel damage. If blast direction was inside then expect to see the cabin floor being lifted. If the blast direction was outboard then expect to see more damage and not radiating from a small point in the middle of the hole in fuselage.

Oxygen bottles just don't explode like this, if it was contamination from galley waste that triggered the explosion combining with small leak from cylinder then again the regulator is where that would have occurred.

Yes there is at least one bottle missing but only because the structure supporting it has disappeared.

THINK AGAIN.

LoL! Despite the dogmatism of "Vortsa" ,(an oxygen bottle vender?:}) that it can't blow up, tank shrapnel has been reported as rumor by one source. As remote as the odds are, it now appears we lost a bottle(s) in this incident. The question of course now is, was the bottle bursting a secondary result of something else impacting it, or did it cause the hull/floor failure in the first place?

This is the first time I've ever heard of a bottle failure in flight...... very odd. Anybody else ever hear of a bottle failure on an inflight jet? (no, Valuejet in the Glades doesn't count.)

[Capt Kremin]

An unnamed senior Qantas pilot


So some engineer rings a tabloid paper and claims to be a senior Qantas pilot? Not only does the Telegraph fall for it, but MAS falls for it and now you do.

How intelligent are you?

[HarryMann]

The plane had received a new interior at Victoria’s Avalon airport in March.

Possibly worth noting!

[wing surfer]

my sources tell me that all of VH-OJK's Heavy Maintenance has been carry out on Australia's soil this aircraft has never been to an outside MRO.

This you can count on as being fact

[lomapaseo]

Machaca

Sleeping Freight Dog -- a closer look shows no bottle under the earlier spotted (Broadreach & Leodis737) frame section that ended up inside and turned around:


I'm not familiar with the terminology being used here. Are you suggestiing that what we see is a piece of outer skin or rather an interior bulkhead :confused:

[Machaca]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2008-0410; Directorate Identifier 2007-NM-362-AD;
Amendment 39-15485; AD 2006-12-10 R1]

RIN 2120-AA64

Airworthiness Directives; Boeing Model 747-400 Series Airplanes

http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAD.nsf/0/64e479c5774b841786257433004f6434/PDF_Field/0.494%21OpenElement&FieldElemFormat=gif (http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAD.nsf/0/64e479c5774b841786257433004f6434/$FILE/2006-12-10%20R1.pdf)


http://rgl.faa.gov/icons/collapse.gif (http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAD.nsf/0/64e479c5774b841786257433004f6434%21OpenDocument&ExpandSection=-3#_Section3)Preamble Information
AGENCY: Federal Aviation Administration (FAA), Department of
Transportation (DOT).


ACTION: Final rule; request for comments.

SUMMARY: The FAA is revising an existing airworthiness directive (AD) that applies to certain Boeing Model 747-400 series airplanes. That AD currently requires inspecting the support bracket of the crew oxygen cylinder installation to determine the manufacturing date marked on the support, and performing corrective action if necessary. This new AD retains all the requirements of the existing AD and expands the applicability of the existing AD to include certain airplanes that are not on the U.S. Register. This AD results from a report indicating that certain oxygen cylinder supports may not have been properly heat- treated. We are issuing this AD to prevent failure of the oxygen cylinder support under the most critical flight load conditions, which could cause the oxygen cylinder to come loose and leak oxygen. Leakage of oxygen could result in oxygen being unavailable for the flightcrew or could result in a fire hazard in the vicinity of the leakage.


DATES: Effective May 7, 2008.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in the AD as of May 7, 2008.
On July 17, 2006 (71 FR 33604, June 12, 2006), the Director of the Federal Register approved the incorporation by reference of Boeing Special Attention Service Bulletin 747-35-2114, dated December 19, 2002.

[aussiepax]

Some posters have alluded to other subsequent failures in this plane.

Does this relate to the cockpit avionics faiiling ?

Pilot relies on skill to land crippled jumbo - Travel - smh.com.au (http://www.smh.com.au/news/travel/pilot-landed-on-instinct/2008/07/26/1216492803343.html)
QANTAS pilot John Bartels landed his stricken passenger jet manually after the auto-pilot and instrument lights were rendered useless by an onboard explosion (sic).

[wing surfer]

Imeo,

the plane is made up of basically stringers and Frames, the stringers run the length of the aircraft, and are connect to the Frames, The frames are the major piece of superstructure that go are the circumference of the Aircraft.

It would appear at first look at these pictures that there is a peice of frame that looks like it has broken away and is sitting at the bottom af the hull breach.

[Nepotisim]

Can everyone stop with the "Corrosion under the galley" statements.

Fact. The galley is aft of door 2 right.

LAME 19 years.

[Machaca]

Lomapaseo

I'm not familiar with the terminology being used here. Are you suggestiing that what we see is a piece of outer skin or rather an interior bulkheadhttp://i337.photobucket.com/albums/n385/motidog/FrameStringers.jpg

Frames are the "hoops" that run the circumference of the fuselage, and to which the longitudinal stringers are connected. The skin panels are then attached to them both.

Yes, it appears to me that object in question is a piece of frame, or a length of skin with a stringer attached that is bent 90º to appear on edge.

[lomapaseo]

Machaca

Frames are the "hoops" that run the circumference of the fuselage, and to which the longitudinal stringers are connected. The skin panels are then attached to them both.

Yes, it appears to me that object in question is a piece of frame, or a length of skin with a stringer attached that is bent 90º to appear on edge.

OK, I was using the word bulkhead for what you call a frame. But I'm still having trouble resolving from the incident picture what you show in the reference picture that you just posted. Could you circle or other wise identify on your reference picture what we think that we are looking at in the incident picture. My belief is this is critical to the chicken and the egg of what failed first

[peter mcgrath]

Yes, it appears to me that object in question is a piece of frame, or a length of skin with a stringer attached that is bent 90º to appear on edge.


So I guess the question is, did the frame at the bottom of the picture that has been twisted 90° get that way before the explosion, or as a result of the cargo shifting after the hull has been sucked into the void?

(edited with frames in correct location)

http://img71.imageshack.us/img71/7773/20080727151703de7.jpg

[pacplyer]

Hey Machaca,

The oxy cylinder we think we are seeing is lying flat horizontally actually on top of the "frame" section you guys are discussing. Go to the absolute lower left corner of the torn skin opening and you can just barely make it out (under Peter's added word "frame".) In the bottom aft corner you can see what appears to some of us as the bottom of the composite bottle (far different from the appearance of the bottom an older style metal bottle.)

See it?

Main Oxygen cylinders on 747-100's and 200's were white, when I flew it. A walk around bottle would be green and is not a part of this conversation.

[HotDog]

The oxygen cylinder assemblies each include a slow openeing shutoff valve, a pressure gauge, and a safety outlet device which bursts before pressure reaches a value that could damage the cylinder, tubing or components. The safety outlet device outlets are manifolded to a line which runs to an overboard discharging port in the airplane skin.

http://i106.photobucket.com/albums/m246/adamtakach/Image0001.jpg

I find it difficult to reconcile the above facts with the bottle burst theory.

[Scissorlink]

Entries on an online aviation forum going back to February revealed that rust had been found during a refurbishment of the 17-year-old aircraft.
One of the posts spoke of "serious corrosion issues" that had delayed its launch date back into service.
"Let's keep our fingers crossed and hope OJK [the aircraft's identification] recovers from her plastic surgery," the forum writer added.

Quote from NZ herald, theyre watching

[HotDog]

The passenger oxygen bottles are restrained in cradle type racks, securely fastened in a horizontal position in the ceiling of the forward cargo compartment. Suggestions of cylinder damage from mishandled cargo or pallet loading is not likely.

[aussiepax]

quote from news.com.au :

Qantas ordered to inspect oxygen bottles | The Daily Telegraph (http://www.news.com.au/dailytelegraph/story/0,22049,24084852-5001028,00.html)

QANTAS has been ordered to urgently inspect every oxygen bottle aboard its fleet of 30 Boeing 747s after a mid-air explosion forced a jumbo to make an emergency landing in the Philippines on Friday.
The Civil Aviation Safety Authority (CASA) expects the inspections to begin by tomorrow and be finished within a few days.

CASA spokesman Peter Gibson said Qantas would be asked to check each oxygen container and the brackets holding the containers.

"It will be a visual inspection and it is a precautionary step," Mr Gibson said.

"The inspection will take a couple of hours for each plane so it will take a few days to do them all."

[Machaca]

Peter -- great image!

Pacplyer -- do you see a bottle end in the photo in post #393? I'm trying to see it, but I'm not making it out.

HotDog -- yes, the bottle supports which are the subject of an AD!

Like our beloved aircraft, even top quality bottles engineered, manufactured and serviced to high standards can fail.

[Kuntrol_Freek]

All this mobile phone footage - and I thought mobile phones were all supposed to be switched off in flight.


Maybe the "explosion" was triggered by a passengers mobile phone ;)

[peter mcgrath]

The oxy cylinder we think we are seeing is lying flat horizontally actually on top of the "frame" section you guys are discussing. Go to the absolute lower left corner of the torn skin opening and you can just barely make it out (under Peter's added word "frame".)


I'm not sure if there isn't actually a second frame (above & below my word "frame") that looks like it has been sliced off at the same horizontal position and pushed 90° just like the frame next to it... same chicken or egg question though...

How much force would be required to slice through 2 frames like that though - and the edges appear to be cleanly sliced through...

[HotDog]

HotDog -- yes, the bottle supports which are the subject of an AD!

Correct, except for the fact that the AD is in respect of the Crew Oxy bottles which are situated immediately aft of the aft sill of the Fwd Cargo door at STA700. The hole in the fuselage is at STA950.

SUMMARY: The FAA is revising an existing airworthiness directive (AD) that applies to certain Boeing Model 747-400 series airplanes. That AD currently requires inspecting the support bracket of the crew oxygen cylinder installation to determine the manufacturing date marked on the support, and performing corrective action if necessary. This new AD retains all the requirements of the existing AD and expands the applicability of the existing AD to include certain airplanes that are not on the U.S. Register. This AD results from a report indicating that certain oxygen cylinder supports may not have been properly heat- treated. We are issuing this AD to prevent failure of the oxygen cylinder support under the most critical flight load conditions, which could cause the oxygen cylinder to come loose and leak oxygen. Leakage of oxygen could result in oxygen being unavailable for the flightcrew or could result in a fire hazard in the vicinity of the leakage.

[NSEU]

The bottles are a major maintenance item only. I don't remember any hatch or access to that part of the aeroplane.

Unless I'm going colourblind, the large green bottles on QF are easily accessible from the inside of the cargo via press-stud & zipper secured fabric panels (glassfibre tape may be seen covering the press studs for extra smoke/fire protection). Green indicates breathing oxygen, rather than pure oxygen. Bottles on QF are occasionally removed for inspection, but as a rule, they are left undisturbed. Qantas tops up its oxygen via a fitting just forward of the Forward Cargo door. In North America, regs makes things rather difficult for servicing as the bottles have to be removed to be topped up. They are somewhat larger than scuba tanks and can be quite heavy and awkward to handle in a confined space.


a times online article indicated that the pilots had trouble with their oxygen supply...and that there was a secondary supply

There is no secondary supply other than the portable bottles in the cockpit (one on the bulkhead, one inside a stowage bin with roll-down door).

Even the so-called Boeing spokesperson got things wrong. There are definitely not "dozens of bottles".

[Brian Abraham]

What sort of corrosion protection is used on the inner surface of the pressure hull? The photo of the piece of metal which has been twisted outwards seems to be bare metal (which I'm positive can't be right, eg must be alodined or etch primer) where an overlay of brown material (paint?) has been eroded.

[woollcott]

Brian, the brown stain is the beloved Ardrox a corrosion preventin coating, similar to waxoyl or LPS 3. Beneath that is a white durethane paint, and beneath that is BMS10-11 primer.
Beneath that is the alodine ( another corrosion prevention treatment) treated skin

[pacplyer]

NSEU said:
There is no secondary supply other than the portable bottles in the cockpit (one on the bulkhead, one inside a stowage bin with roll-down door).

Even the so-called Boeing spokesperson got things wrong. There are definitely not "dozens of bottles".
Today 22:55


Really? There's no automatic shuttle valve between flight crew tanks? That could be considered a "secondary source" even though the crew does not have to select it......

Are you sure that all the lower hold crew oxy supply bottles (fleetwide) are not composite and coulored white? You're positive about this? :E

[fc101]

Rainboe wrote:
Can any divr say what happens if all the gubbins on the end of an Oxygen cylinder blows off suddenly? Or the end blows off? What happens to the bottle?

Extremely unlikely but two things can happen: failure of the valve - never seen this happen but as they're screwed in then this generally means complete failure of the cylinder. There is alledgedly one incident form the 90s in the UK where this happened in a traffic accident - said cylinder took off like a rocket (but sounds like Daily Mail reporting to me)

Cylinder failure: usually seen as a tear in the side of the cylinder. Never known an end to blow off (try this with a bottle of coke) ... while structurally possible the sides are the weakest point.

Diving cylinders must be pressure tested every two years and visually inspected by removing the valve and looking inside every four years. (UK, Europe rules IIRC )

I've never heard of a diving cylinder failing spontanously - after dropping or during filling yes...

The most common form of O2 accidents is getting oil., grease or hydraulic fluid around the valve....

[londonman]

In reply to fc101....

...Diving cylinders must be pressure tested every two years and visually inspected by removing the valve and looking inside every four years. (UK, Europe rules IIRC )

Just because the rules say this, doesn't mean that every cylinder is pressure tested. There are cowboys in every field of human endeavour.

[zumBeispiel]

Missing oxygen cylinder in Qantas plane






July 27, 2008

AN oxygen cylinder is missing from the Qantas 747 jumbo that was forced to make an emergency landing after a mid-air explosion punched a hole in its fuselage.
The Civil Aviation Safety Authority (CASA) is investigating whether an exploding oxygen container was responsible for ripping a jagged hole in the fuselage of flight QF30 from London to Melbourne last Friday.

The Boeing 747-400 was cruising at 8800 metres with 346 passengers aboard when it was shaken by the blast.

But the aircraft managed to land safely minutes later at Manila airport, leaving passengers and crew unhurt but badly shaken.

"It is too early to say whether this was the cause of the explosion," Neville Blyth from the Australian Transport Safety Bureau (ATSB) told a media briefing in Manila this afternoon.

"But one of the cylinders which provides back up oxygen is missing."

Mr Blyth told the conference investigators had found no sign a bomb caused the hole.

"There is no evidence of a security related event here," he said.

"Philippine bomb sniffing dogs have inspected the baggage and found no materials of concern."

CASA spokesman Peter Gibson earlier today discounted a report that corrosion was to blame, but the issue of corrosion in general would be investigated.

Mr Blyth said the investigation would take two to three days and a full report on the findings "should be released in two to three months."

With AFP

[Deaf]

"said cylinder took off like a rocket (but sounds like Daily Mail reporting to me)"

That is exactly what does happen. Saw the results of a nitrogen cylinder which was dropped (~10 ft) breaking off the valve. Went through a couple of glass doors, assorted vegitation and finished up against a wall ~200yds away.

A blast of HP gas from a failed manifold/valve would have quite an effect on the skin and associated structure. Lot of energy in HP gas as shown by the tyre burst in the prototype Bucaneer which disassembled the wing during taxi test.

The tank doesn't need to burst, the gas just needs to get out in quantity at several thousand psi

[Nemrytter]

I've seen a pressurised tank fail (not oxygen, but the pressure level and construction were similar). It had gotten a little ding on the side during transit and while we were filling it the entire side let go, the tank was propelled about 20ft and made a hell of a mess of it's surroundings.

I don't have any experience with aircraft pressure vessels, so I'll limit my comment on that to saying that if one of these oxygen tanks did rupture then it could easily cause all manner of problems, the energy in those things is amazing.

[Keefie]

Interesting though the camera shots by a pax were, they were taken illegally. It may sound niggardly to protest in such circumstances, but even a minor avionics blip in such circumstances could prove fatal:=

[FlexibleResponse]

Illegal camera use
Interesting though the camera shots by a pax were, they were taken illegally. It may sound niggardly to protest in such circumstances, but even a minor avionics blip in such circumstances could prove fatal

See below for "Flight Mode" capable phones:
About Qantas - Newsroom (http://www.qantas.com.au/regions/dyn/au/publicaffairs/details?ArticleID=2005/aug05/3301)

[Long Bay Mauler]

Has anybody suggested that there may have been a metalurgical defect within the body of the oxygen cylinder?

Although defects like this are supposed to be picked up in NDI inspections during manufacture of bottles,its not improbable.

If I remember correctly,this is what happened to a DC-10 engine turbine wheel in the mid 80's.There was a defect subsequently missed numerous times during manufacture and normal overhaul NDI,that eventually failed and destroyed the engine and thus the aircraft.

Any one with experience in manufacture/overhaul of oxygen bottles think this is plausible?

[point8six]

Just a couple of points:-
Boeing 747-400 Flight Crew Training Manual has an illustration of 'altitude versus time' for rapid descent, and interpreting it the descent from FL290 to FL100 takes just over 2 minutes ( the high speed, no structural damage case and the lower speed, gear-down option, apparently little different).

The manufacturer offers the option in the Pax oxygen system of either supply oxygen (i.e. the O2 flows through every mask regardless of number of pax) or demand ( pax are briefed to pull the mask to initiate flow). Perhaps a QF eng. can state which system VH-OJK has? If it is the latter, then some pax reporting a lack of O2, may not have pulled the mask.

On depressurisation or activating the Pax. Oxy switch in the cockpit, an automatic announcement is played and repeated over the PA system. While it sounds loud enough during Cabin Crew pre-flight checks, it may not be very loud during the actual event - perhaps not sufficiently loud enough to get the attention of confused and frightened pax.

[thelummox]

A look at the metal deformation around the edge of the breach gives you some indication that there was possibly a rapid expansion of gas or vapour. The short sections of stringer that remain attached to the folded skin at the top of the photo clearly show signs of sudden outward pressure, witnessed by the torn edges. The skin around the edges of the opening is clearly sharply torn with an outward fold around. Now I wouldn't even offer you a guess ( that's why we pay the ATSB to do a job) but as someone who has spent some quality time on demolition ranges, an uncontained explosion, or expansion, inside a vessel will find it's way via the weakest point to the outside as quickly as possible. Which is why when objects such as cars get sent to a better place, all the fragmentation and remains are sharply torn in the outward direction. There are plenty of industrial engineers and likely metallurgists on the site. The damage to the stringers, the skin and direction of folding should give these guys hours of discussion.

Anyways, despite the unfortunate incident ( I'm sure Geoff Vader still hopes it might buff out!) it stands as a testament to the ruggedness of a design that first flew forty years ago

[aussiepax]

Quote:
Illegal camera use
Interesting though the camera shots by a pax were, they were taken illegally. It may sound niggardly to protest in such circumstances, but even a minor avionics blip in such circumstances could prove fatal
See below for "Flight Mode" capable phones:
About Qantas - Newsroom (http://www.qantas.com.au/regions/dyn/au/publicaffairs/details?ArticleID=2005/aug05/3301)
http://www.pprune.org/forums/images/statusicon/user_online.gif http://www.pprune.org/forums/images/buttons/report.gif (http://www.pprune.org/forums/report.php?p=4291661)


Exactly. Seeing as they were beyond "top of descent" for obvious reasons, all these elctronic devices should have been off, no matter what their status.

[HotDog]

Jagman1: Yes, your concerns have been mentioned on another forum. However, apart from the following answer, QF 747-400s are fitted with extra oxy cylinders for terrain clearance.

Every flight plan calculates all contingency range configurations including engine/critical systems failure and depressurisation. The SYD-EZE route will be planned in accordance with CAR's, CAO's, AIP's etc and the route will be such that the aircraft will have sufficient range to divert to a suitable airport at all stages of the flight. Some posters on this thread have commented that it was lucky that this event did not happen on the previous sector wrt high terrain adjacent to the Tibetan plateau. Every segment of that route has been analysed and "Escape Procedures" have been published (& which both pilots at the control seats have in front of them) to take into account Single Engine Failure, Two Engine Failure and Depressurisation cases. By law, RPT operators are required to comply with these requirements and at no stage is an aircraft going to caught in a no option situation.

[BOAC]

Now the focus appears to be settling on oxy bottles, a few questions please:-

It appears the 747-400 pax oxy is bottle/ringmain supplied unlike the 737 (with individual generators above each seat row). Does each mask need to be pulled to generate flow or is it sufficient (as 737) to pull one in each row?

EDITED TO CORRECT MY COCKUP!

[ExSp33db1rd]

BOAC - My memory would go for individual control valves that have to be pulled, if one activated a whole row, which seat ? or would any one of the 3 ( or 4 ) activate a row, if not, what if the subject seat was unoccupied ?

[ByteJockey]

Question: Do the flight crew only have the 'plumbed in' oxygen supply, or do they also have access to the self-contained units that are provided for the flight attendants? I'm assuming they do but I'm just a SLF etc, so I don't know the answer...

[beaglecp]

This is how Reuters, who distributed the footage, described the circumstances:

Dopesheet:
Amateur footage is filmed by one of the passengers on a
Qantas flight that had to make an emergency landing in
Manila after its undercarriage blew off.

[Little_Red_Hat]

Pax oxy sys on this aircraft, as stated previously, is of the 'stored gaseous type'.

Pulling down on a mask will activate o2 flow to THAT MASK ONLY.

Therefore, if pax are too shocked/innattentive to briefing to REMEMBER this, they may NOT have pulled down on their mask- if it was flapping in front of them my guess is they'd remember the part to grab it and put it on- but possibly forgot the part of "Pull down on it firmly"" in favour of put it on quicklÿ, and ensure the strap is tight"

Most pax wouldn't know what a flow indicator is or how to check for oxy flow. (In this case, bag MAY inflate)

Flow can be shut off at individual units/masks when no longer required. Duration would vary on time of descent, number of pax, demand etc...

Yes, flight crew also have backup in the form of a portable bottle similar to those seen worn by the cabin crew in that video.

[ExSimGuy]

As I recall, on the now-very-old 74s of the BA (ex-BOAC) fleet, Flight-Deck Crew have their own O2 bottles, and pax have further bottles (no O2 generators unless they have been subsequently installed.

In the event of Crew O2 failing, then they could "appropriate" the pax O2 (more important that the crew be fully-aware in an emergency!)

[ExSp33db1rd]

Not terribly relevant, but if I were a pax. expecting to die at any minute, I wouldn't be too bothered about rules relating to not using mobile phones in flight ! Taking pictures might just be the very thing that helps solve the mystery of what happens, and of course there are also those unscrupulous individuals who immediately alert the Press in the hope of getting a pay off for their efforts. Personally I'd ban the things along with the excess fluids and other stuff that the TSA and their World Wide Clones steal from pax. these days.

[greenhornet]

I wonder if the oxy bottle blew, due to contamination or some kind of bottle or HP fitting imperfection, or whether bottle went out due to a structural failure that happened to be beside it. I think perhaps a structural failure due to corrosion, and the bottle mounted there got taken out ? Also, wouldn't it be nice for the rest of the crew to be recognised, I'm sure it was a team effort. The dumass media never seem to understand anything about aviation "the pilot saved the plane as it fell out of the sky" for fuxake!

[pappabagge]

An oxygen cylinder is missing from the Qantas 747 jumbo that was forced to make an emergency landing after a mid-air explosion punched a hole in its fuselage, an Australian investigator said in Manila today.
"It is too early to say whether this was the cause of the explosion," Neville Blyth from the Australian Transport Safety Bureau (ATSB) told a media briefing in Manila this afternoon.

"But one of the cylinders which provides back up oxygen is missing."

Meanwhile, the Associated Press said Blyth told the conference investigators had found no sign a bomb caused the hole.

He said tests for bomb residue were negative and Philippine officials had bomb-sniffing dogs go through the hold, finding no indication of explosives.

Qantas ordered to inspect every oxygen bottle
Qantas has been ordered to urgently inspect every oxygen bottle aboard its fleet of 30 Boeing 747s after the mid-air explosion.
The Civil Aviation Safety Authority expects the inspections to begin by tomorrow and be finished within a few days.
CASA spokesman Peter Gibson said Qantas would be asked to check each oxygen container and the brackets holding the containers.
"It will be a visual inspection and it is a precautionary step," Mr Gibson said.
"The inspection will take a couple of hours for each plane so it will take a few days to do them all."
CASA is investigating whether an exploding oxygen container was responsible for ripping a jagged hole in the fuselage of flight QF30 from London to Melbourne.


:D

[peter mcgrath]

Just been reported on BBC World Service that the investigators are considering a possible explosion on this aircraft as having caused the damage. Apparently an oxygen bottle has gone missing.


If indeed the oxygen bottle has gone MIA can someone tell me what this horizontal white cylindrical object is (behind the stringer & rotated frame)? When the photo is enhanced it becomes quite apparent.

http://img247.imageshack.us/img247/7728/20080727200205ei7.jpg

[digiteyes]

The O2 cylinders in question are definitely those of the pax system.

From the 744 systems manual:

"The passenger oxygen system is a continuous-flow system that automatically provides oxygen for passengers whenever the cabin pressure altitude reaches a nominal 13,875 feet or higher. During the first few seconds, the control unit produces a pressure surge that releases the oxygen mask stowage doors and permits the masks to drop within reach of the passengers"

Given that the pax O2 system had been 'compromised'.. it's probable that insufficient pressure was available to all mask stowage doors, preventing some from opening.

Similarly, insufficient O2 pressure in the distribution system may have resulted in a reduced amount/loss of O2 available at some locations.

This is my opinion only (as a pilot, not as a LAME).

[BOAC]

DELETED DUE TO MY MISREADING:mad:

[greenhornet]

If a high pressure oxygen leak started, a 100% oxygen atmosphere would start a fire with the slightest oil based contaminant or even heat from friction. A blow torch fire would result until the oxy ran out, not a bang. No sign of fire here, so I don't think that happened. An explosion of the bottle is very unlikely also, it is an aircraft quality component that would be regularly inspected/replaced, and I've never heard of a cylinder failing like that? I don't like the look of the way that rivet line has fully seperated from the stringer in the picture. Does anyone know if a cylinder is missing here, or is the cylinder shown in the picture the only one in this area?

[HotDog]

Peter mcgrath, the cylindrical object you refer to looks like an air supply duct to the ACMs. Definitely not an oxygen cylinder which are coloured green (aviation grade breathing oxygen).

BOAC you have misunderstood my post #417. I did not claim the explosion occured near the crew oxy bottles. I merely pointed out the intent of the Boeing AD which refered to the crew oxygen stowage brackets. The hole in the fuselage was well aft of the crew oxygen location.

[empire4]

FYI: oxy bottles are green, fire bottles are silver. The white long bit of metal in the photo i would guess to be the foot rail we engineers stand on to change oxy and fire bottles. they are intergeral to the cargo bay and sit just under the edge of where a container would sit

[BOAC]

Sorry HotDog - I blame it on the current heatwave here:} Posts edited. Thanks for pointing it out.

[fatcat69]

Lets stop saying the word explosion. There is no ignition, no charred remains, no evidence of heat.

At worst there has been a rupture of a green oxy bottle that may have caused a press bubble that cause a failure of the surrounding structure..

So how could this be possible? If the gas in the bottle expanded it would escape through the relief line.. the little green disc you boys and girls check each dept.

If its not that then could the bottle have been allowed to get to zero press introducing moisture to the bottle. It is then recharged and the cycle of corrosion begins from the inside out? All bottles have a hydrostatic test date to ensure this still cant happen.

If the airframe structure failed first it is logical the nearest thing to the hole would be missing being the bottle.

If it was the bottle how did it open up the can and release all the bags?

This is a case for the X Files.

The big white thing looks like a side shot of a floor beam to me, look at a wider angle shot for a reference to the cargo door lwr edge which is floor level...

Too many questions yet to be half right :sad:

[beamender99]

From todays UK Sunday Bellylaugh

The item is headlined:
Inspection found rust on Qantas jet in February

This report is from Sydney by Barbie Dutter

[peter mcgrath]

The big white thing looks like a side shot of a floor beam to me, look at a wider angle shot for a reference to the cargo door lwr edge which is floor level...


Cargo door lower edge seems to be a way below the white cylinder...
http://img180.imageshack.us/img180/4852/20080727213046wv6.jpg

[TWT]

Peter McGrath,

What makes you think the 'white thing' is a cylinder ?

[jhurditch]

The descent procedure is usually a quick check over of the packs, manually selecting outflow valves to closed and then dialing in 10000 into the alt select and then hitting the FLCH. Usually Vmo for max performace so your descent speed is at the barber pole. Speed Brakes extended, gived you ALOT of terrain out the windows, usually stabalised at 4-5500 fpm. even higher sometimes

[headpropeller]

For a few posts it was good to see what the posters' area of expertise was. So, let me state at the start that I have none relating to the subjects on discussion.

Anyhow, having followed this thread for last two days and read most (if not all) post which did not concern themselves with media context, I cannot recall comments on couple of aspect of the damage.

If we were to fold back the three of so main pieces of fuselage skin, where would the centre of the break be? The way I see it - right along the lap joint. Look at the angles the lower and upper tears on the right diverge away from each other. The top part with two stringer chunks reaches down close to lap joint. I'd say, that oxy tank must have hit bullseye. I'd rather side with recent posts - "dislodged and out the hole" tank more plausible than a rocketing one.

Back to the broken skin. On the lower part blown outward, it looks to have an inward folded edge, which also looks to be curved. Or, is this just an illusion on a 2D photo?

Just curious.

[KiloB]

The 'bent outwards' piece of hull near the top of the picture has a suspiciously even and rounded edge on one side. Almost as if it got in the way of a cylinder going somewhere in a hurry!

[LapSap]

Qantas jet probe focuses on missing oxygen cylinder | Herald Sun (http://www.news.com.au/heraldsun/story/0,21985,24085389-661,00.html)

Passengers praised the crew's handling of the incident, but some complained that not all the oxygen masks worked properly.

"The elastic was so old that it had deteriorated. I was trying to get my passport, and every time I got my passport the mask fell off and I started to pass out," architect David Saunders told Fairfax.


I'm worried about David's sense of priorities.:suspect:

[HotDog]

ByteJockey;

1. The AD refers to the Crew Oxy brackets heat treatment procedure.

2. The Oxy cylinders lay horizontal in a U-shaped cradle with
two security brackets locking it down.

3. 4. 5. no longer follow.

http://i106.photobucket.com/albums/m246/adamtakach/Image0001-2.jpg

[Rabid Dog]

Sound speculation though ByteJockey. (to my un-engineering self).

[MUNT]

Usually Vmo for max performace so your descent speed is at the barber pole

Unless the integrity of the airframe is in doubt. I'd suggest having heard the failure as an 'explosive' noise they wouldn't have been decending at vmo.

[jhurditch]

In remark to the passenger quote
Passengers praised the crew's handling of the incident, but some complained that not all the oxygen masks worked properly.

"The elastic was so old that it had deteriorated. I was trying to get my passport, and every time I got my passport the mask fell off and I started to pass out," architect David Saunders told Fairfax.

Despite the fact that the elastic on the mask was deteriorated, David still had oxygen from what I gather. When one bottle goes, dosn't all the O2, secondly, you would only need to check the aircraft and make sure each oxy mask door was open in the cabin. Wouldnt that be enough to explain if the oxy bottle had failed or not?

[Green-dot]

To KiloB:
The 'bent outwards' piece of hull near the top of the picture has a suspiciously even and rounded edge on one side. Almost as if it got in the way of a cylinder going somewhere in a hurry!

Indeed, like if that piece of structure has been punched out. Like many posters have addressed, an O2 bottle does not just rocket out of an aircraft. There is probably more to the sequence of events which a thorough investigation will reveal.

Also, it is not possible to tell from the pictures how large the initial hole was. I do believe, however, a force large enough to punch out the skin also took out the lapjoint and thus, was part of the initial damage done to the structure. Decompression and aerodynamic forces probably made the hole much larger, ripping away jagged pieces of structure which were fluttering in the disturbed airflow due to the shattered fairing which most likely separated from the aircraft at the time of the structural failure.

Regards,
Green-dot

[Seat62K]

LapSap,
Having experienced an emergency landing as a passenger (the real thing, including the "brace" position) I think I may have some insight into the behaviour of the passenger who wanted to get his passport. As we were descending I had what later struck me as possibly inappropriate thoughts, such as "my car keys are in the overhead locker; that means if I'm forced to leave them I'll have to find a alternative way home and return to Gatwick just to pick up my car. Or, as I'm flying again from Gatwick next week, should I just leave my car there?". Perhaps I, too, should have had different priorities...or perhaps this is one ways the mind diverts someone from dwelling too much on the reality of the situation.
P.S. Apologies for the thread drift.

[Speedbird61]

Did anyone notice on the footage that a passenger recorded, the Cabin Crew had a meal cart in the isle, and it looked as if they were serving meals like nothing had happened, anyway looked a bit strange to continue the meal service in the middle of an emergency.

[Scimitar]

(Retired 757/767 captain)

Can anyone tell me (Rainboe maybe?) how the pilots would know that they were not breathing O2 if their cylinder had disappeared? My memory of performing and watching countless Rapid Depressurisation scenarios in the simulator is that the initial actions were;-

Oxygen masks and regulators...... ON, 100% (and the 100% was set pre-flight)

Crew Communications.... Establish.

So long as the flow to the masks was not restricted in some way I'm not sure they would know that there was no oxygen flow. Perhaps the 744 has a crew bottle contents guage or a Status message will appear.

Any ideas folks?

[Litebulbs]

Look at the second picture on post 359. Look at the top left corner of hole, where a major piece of skin is bent upward. You have the green coloured aircraft skin, but inside of that, you can see the slightly darker coloured green, of an O2 bottle still in situ. Now the missing bottle/bottles and relevant supply pipework, would be where the hole is, moving forward to the front of the aircraft. I imagine that passengers may have trouble with their O2 supply, with quite a large percentage of the system missing. I do not suppose Boeing, when designing the system, built in fail safes for completely missing bottles within the system, which also by its very failure, possibly caused the decompression which the system was there to protect against!

As to starting the supply to the mask of each individual passenger and if the design has not changed from -200 days, you would pull the mask towards you and a length of cord attached to both the mask and a plastic pin in the oxygen drop down assembly supply manifold, would be removed, so allowing supply to the mask.

[lomapaseo]

A few general comments.

A jet propelled oxygen tank takes a fair amount of travel distance in meters or yards to get up enough velocity to punch through aircraft skin. (reference the Mythbuster documentation on TV)

Exploding oxygen tanks leave smaller fragments behind to pepper the inside skin.

The support for the oxygen tanks is very likely to be compromised when the fuselage ruptures nearby.

Explosive decompressions create pressure gradients across nearby large area surfaces which in turn cause them to accelerate outward towards the hole.

To my knowledge no investigator is saying the oxygen containers ruptured first.


Anybody got any better schematics or pictures to corral this discussion:)

[DarkSoldier]

Did anyone notice on the footage that a passenger recorded, the Cabin Crew had a meal cart in the isle, and it looked as if they were serving meals like nothing had happened, anyway looked a bit strange to continue the meal service in the middle of an emergency.

I think they were clearing the trays away rather than serving them...

[Desertia]

Australia's Civil Aviation Authority (CASA) said Qantas has agreed to inspect oxygen bottles on its fleet of 30 747s.

CASA spokesman Peter Gibson said: "There are two cylinders located pretty much exactly where that hole appeared."

He added: "We do know there were two oxygen bottles in that area, we do know they're a main focus of the investigation, and we think it's prudent to put safety first, to get inspections done now rather than wait any longer."

Smug grins all round then from people who suggested tanks in the first place.

I still like meteors myself, there's a new Airport movie in that, surely :8

[Xorthis]

Despite the fact that the elastic on the mask was deteriorated, David still had oxygen from what I gather. When one bottle goes, dosn't all the O2, secondly, you would only need to check the aircraft and make sure each oxy mask door was open in the cabin. Wouldnt that be enough to explain if the oxy bottle had failed or not?

Afaik passenger emergancy oxy is delivered from chemical oxy generators directly attached to the masks above the passengers. You have to pull the masks down firmly to release a fireing pin which starts the chemical reaction. The larger oxy tanks are for the crew's masks as these passenger oxy gens only work for about three minutes, just enough time for the crew to decend to 10,000ft.

[sevenstrokeroll]

as pilots, the donning of the oxygen mask is a vital part of our training...but there has been very little in the way of...OXYGEN NOT FLOWING...what do I do now?

certainly manipulating the toggle switches...but to have it fail and then get out the walk around bottle is alot to ask.

I do think the whole planeload was lucky that the plane was at FL290 and not higher.

While I know the everglades/valujet crash was due to the oxygen generators (and fuel...tires in cargo hold), few may remember that the lines to the oxygen regulator had been compromised even prior to flight.

I sure hope the brave QANTAS pilots had actually checked their oxygen masks before flight by placing them on their face and breathing...under pressure.

[digiteyes]

Xorthis,

If you scroll up to my post #443, it explains the 747-400 passenger oxygen system.

It is a reticulated system using stored O2 cylinders, not generators.

[Vertiginous]

Splendid graphics, Peter! Looks like a stringer to me. As to which one, we have plenty of choice. :) If it failed concurrently with everything else, would it not be in the South China Sea right now? This seems to suggest that it got wedged inside at this interesting angle before the failure of the skin.

[Yamagata ken]

"The reason for our retirement was electrical failure. The con-rod broke through the side of the block and destroyed the alternator. "

Ho hum. The reason why the oxygen bottle is missing is because the piece of airframe to which it was attached is somewhere at the bottom of the Pacific.

[I Just Want To Fly]

Cabin Crew here.

As far as I am aware, the decompression happened during or immediately after the meal service, meaning 365 would have had their layups. I agree that the crew were most likely clearing in those lay ups.

Personally, I would have gone through with our big garbage bags, and just chucked it all in, EasyJet style. I think we could clear in a 744 in about 10 minutes that way.

Following the descent, it may have been considerable time before landing into MNL. I presume the a/c also flies at slower speed at 10,000. Another theory is they were serving juice or water. Keeping the crew busy during an emergency is very important as it helps us remain calm and therefore more able to calm and reassure the pax. Not sure I'd do it on a cart though.

Congrats to all the crew, my thoughts are with all my friends who fly for the Q!

[lomapaseo]

Splendid graphics, Peter! Looks like a stringer to me. As to which one, we have plenty of choice. If it failed concurrently with everything else, would it not be in the South China Sea right now? This seems to suggest that it got wedged inside at this interesting angle before the failure of the skin.

Except if it failed at a rivet line along the skin then the outer skin is compromised as well.

I am still hoping that some of our graphics artists could transpose that fuzzy piece in the incident picture to overlay the clear interior reference photo that Machaca posted.

[SUB]

All wet areas and bilges are painted white, notice alot of bare aluminium skin on the upper folded peice (inner surface), could that paint be missing due to oxygen blast onto the skin, how else does this paint go missing or removed ?? Zoom up and have a look.

[Vertiginous]

There's been a suggestion that some sort of fire or pyrolytic reaction is implicit in an 'explosion' — that chemical explosives are needed, and scorch-marks will ensue. This is not the case. An explosion is any rapid and uncontrolled evolution of gas. It doesn't matter what the gas is, or how you achieve it.

An explosive is a material which, when detonated, undergoes an extremely rapid chemical reaction involving the evolution of a colossal volume of gas very quickly. Detonation is the process of raising the chemical system above the energy level required for the reaction to take place.

An extremely large volume of gas being rapidly liberated from a fragmenting cylinder is an explosion.

As to the likelihood of fire being associated with an O2 leak, it's not compulsory: if there's no ignition source to hand, there will be no fire. There are materials that will spontaneously combust in pure O2, but we're not likely to see any of those in the hold of an aeroplane.

Finally, yes, a rocketing gas tank would need to accelerate for a few metres to knock a hole in a seam, but that folded-up bit of fuselage is interesting nevertheless. Were there any gas tanks in that hold other than the ones that were (theoretically) bolted to the sides? Any scuba enthusiasts on board?

[tristar 500]

I know it`s some years since i worked on the Qantas 747-400 but some points need answering from memory.

1st There are several bottles in the rack 6 or 8 from memory. there is a non return valve between each bottle so the loss of one especially at the end of rhe line would not drain all the others.

2nd The way the bottles are secured it is very uinlikely that the bottle exited the aircraft in one peice, I would suspect a bottle failed & the shrapnel caused the damage.

3rd The crew have their own supply of oxygen totally seperate from the pax supply.

tristar 500

[bcgallacher]

Early 747 had the passenger O2 bottles horizontal in the roof of the forward cargo area opposite the door - later 747 have the bottles mounted vertically in the right sidewall of the cargo area aft of the crew bottle stowage .

[pappabagge]

"...the system, which also by its very failure, possibly caused the decompression which the system was there to protect against!"

Nicely put!:D

[Dairyground]

From the passenger video from post #154, it appears that the FA were handing out trays and serving drinks rather than clearing up - see about 40 seconds in for a tray being handed to seat D or E. There is also a shot that seems to show a coffee pot being wielded.

This was all happening after the "plunge", as the seat-back display shows altitude 10002 feet and ground speed 348 miles per hour. Another video in the same set shows the seat C passenger still with a tray and altitude going down through abot 9500 feet.

With the order of an hour to go to Manilla and things more or less stable, it seems reasonable that the cabin crew should maintain normal service. That would give everyone less time to worry!

[birrddog]

With all this talk of oxygen bottles making the hole, incl. the Frames/Stringers/Skin/Cargo, etc. that did exit the hole....

I am amazed, especially noting the location of the damage that no other part of the aircraft was hit by the debris....

Is this luck or are there reasons why this would not occur?

I'd happily accept luck!

Well done to the crew, and glad everyone made it down safe.

[Furriskey]

On the very few occasions since I started flying (TAROM, Bucharest 1958) when I have been frightened, I too have had inappropriate thoughts, although these have seldom concerned the whereabouts of my passport. In the current case can I just say, without being excoriated by Rainboe, that this incident has simply served to increase my trust in the 747 as one of the safest machines ever to grace our skies.
Almost unbreakable. I for one will miss them sadly when they are gone. And I remember with particular gratitude being whisked out of a riotous Jakarta not so long ago on a Qantas SP. Great plane, great crew.

[PaperTiger]

Finally, yes, a rocketing gas tank would need to accelerate for a few metres to knock a hole in a seam, but that folded-up bit of fuselage is interesting nevertheless.If we are to believe the report of the first 'clunk' (20 mins ex-LHR), is it not possible that was the alleged bottle dislodging ? After which it could have rolled around down there sustaining increasing damage until it finally let go from an undetermined position; conceivably the necessary 'several metres' from impacting the skin.

Speculation. So sue me.

[lomapaseo]

Speculation. So sue me.

My lawyer will be contacting you shortly

You seem to pre-suppose that there is lots of room down there to move arround in and get it up to speed

[Blacksheep]

You seem to pre-suppose that there is lots of room down there to move arround in and get it up to speed There seems to be a lot of pre-supposition that an oxygen bottle exploded, when the only fact we have is that one is merely missing.

Gas tank explosions are exceedingly rare and as far as I can recall we've never had one explode in the air. The very few occasions where bottles have failed were during in-situ ground charging (which is possibly the reason why we don't do that any more.) Anyone who watched the Mythbusters going about their hilarious business would know not only how difficult it is to break the neck off a gas bottle, but how slowly it accelerates when you do succeed. Impressive it may be, but a rocket it isn't. The bottles in an aircraft are securely clamped into place in any case. When the mythbusters tried busting a bottle as in the Jaws movie, their stunt required several attempts with a 30.30 carbine to get the bottle to burst - with a dead square-on hit to the long edge. Most hits either bounced off or simply punched a bullet sized hole through which the gas escaped with a loud hiss. Gas bottles are tough.

The final point is that an oxygen bottle explosion is extremely violent. An oxygen cylinder explosion, apart from being sufficient to blow a hole in the fuselage, would certainly have blown out the cabin floor (which is simply a lightweight honeycomb sandwich) above the area. We don't see such damage.

If the investigation shows that the fuselage rupture was indeed due to an oxygen bottle exploding, then we have a very serious problem. The bottle is missing - what was its failure mode? Without knowing that we don't know how to prevent a repetition.

[Vertiginous]

I thought the investigators found bottle débris? I swear I read that on this thread. I can't seem to find it now. I think I've got a headache coming on...

[Blacksheep]

It was alleged, but we don't see any in the photograph, despite that wall of luggage stuffing up the hole. One would expect at least some shrapnel stuck in the baggage.

[G-CPTN]

If we are to believe the report of the first 'clunk' (20 mins ex-LHR), is it not possible that was the alleged bottle dislodging ? After which it could have rolled around down there sustaining increasing damage until it finally let go from an undetermined position; conceivably the necessary 'several metres' from impacting the skin.Stopover in Hong Kong.
Would cargo hold door be opened?
(I assume that baggage not for/from Hong Kong would remain in situ, therefore any derangement of the oxygen cylinders wouldn't therefore be noticed?)
Is the area where the hole appeared part of the cargo hold? (I understand that it might be 'curtained-off')

There appeared to be a hole in the cabin floor (I think I saw a picture). Is this directly above the structural hole? Could this be explained by 'suction' from the evacuation of the cabin air through the breach in the structure? There was talk of papers etc flying around the cabin.
OTOH, any upward rupture of the cabin floor would indicate an 'explosion' of some sort (I'm not suggesting a chemical detonation, merely rapid expansion of a gas, as occurs when a child's balloon bursts).

The 'bent back inwards' edge of that failed skin (front of 'hole' http://i24.photobucket.com/albums/c19/GroupCaptain/PhilippinesPanel.jpg
http://i24.photobucket.com/albums/c19/GroupCaptain/PHILIPPINESx2crop.jpg
from:- http://media.aftenposten.no/archive/00816/PHILIPPINES-PLANE___816172a.jpg ) suggests that there was a larger piece attached immediately post-'failure' that was subsequently blown backwards by the airstream before (eventually) being w*nked off (bending backwards and forwards as you would to 'break' a piece of metal by fatigue failure), leaving an inwards bending edge.

[Rainboe]

B747 Pilot 18 years
Just to clear up some points. The B747 does not use individual seat row oxygen generators. There are Passenger and Crew oxygen bottles in separate systems, feeding ring mains- the passenger one goes right around the aeroplane, the crew one just to the Flight Deck. There is no interchange of supply, and the crew one cannot be fed from the passenger system. The passenger system in a full aeroplane may only have a capacity for about 25 minutes, the flight deck crew system considerably longer, but it is a smaller bottle which supplies up to five people. There are no easily to hand alternative supplies on the flight deck. If your ring main system did not work, you would be unable to get to another supply. As for indications that the pilot supply is supplying oxygen satisfactorily, on each pilot's oxygen supply panel where he gets his mask, there is a yellow cross shaped device that changes size as he takes oxygen each breath giving a visual indication that oxygen is flowing. With the commotion of what is going on in the background, I have never known anybody check this in an emergency. Sticking ones head in the forward hold, there is no sighting of oxygen bottles at the rear. I assume access would be through the rear face of the hold somewhere. I have no idea what it looks like or how the bottles are mounted, but they are all fitted with stopcocks and overpressure venting systems, and feed into a common main, therefore they must have NRVs and PRVs individually.

[lomapaseo]

I thought the investigators found bottle débris? I swear I read that on this thread. I can't seem to find it now. I think I've got a headache coming on...

I hope that you don't beleive everything that you read on here :)

About the only thing that you can trust is that relased by the official investigators which in this case is the Australian ATSB. You also have to treat with caution even words like "they are looking very closely at...." being paraphased by news media.

and for gosh sakes this forum is just a discussion forum with many "what ifs" and "probably was" to fill in the blanks in our minds.

at the minimum it at least shows that we care about the subject

[lissyfish]

Vertiginous, see #354 re the initial Bottle Debris quote from the NY Times:

One person close to the investigation, who was not permitted to speak to the media while the inquiry was under way, said Saturday that “some kind of explosion” might have occurred, because the floor above the cargo hold had been pushed up. Two oxygen bottles that supply the pilots are stored in that area.

Australian investigators, who got their first look inside the plane Saturday, discovered shards of an oxygen bottle throughout the cargo hold and in the floor above, which sits below the cabin, this person said. Officials cautioned that it was too soon to know if the oxygen canister had caused the damage, but theorized that it might have played a role, this person said.

...it is just an anonymous source though. So take it for what it is....

[snowfalcon2]

Here is a good picture of the forward cargo hold, in this case from a Virgin 747-4Q8. You can see the cargo door in the foreground. I presume the oxygen bottles are behind the vertical sidewalls furher aft. Those familiar with the 747, feel free to comment.

Photos: Boeing 747-4Q8 Aircraft Pictures | Airliners.net (http://www.airliners.net/photo/Virgin-Atlantic-Airways/Boeing-747-4Q8/0312850/L/)

[grimmrad]

Excuse my ignorance in advance - but nobody mentioned the little door hanging open only a bit towards aft of the whole...?
(interested SLF, no pilot or engineer)

[Machaca]

http://i337.photobucket.com/albums/n385/motidog/QF30-Cargo-Hold-01.jpg



http://i337.photobucket.com/albums/n385/motidog/QF30-Cargo-Hold-03.jpg



http://i337.photobucket.com/albums/n385/motidog/QF30-Cargo-Hold-02.jpg

[Machaca]

Snowfalcon2

The photo you reference (thanks!) leads me to believe the bit of cloth with the letters STA in the incident photos is a portion of the beige nomex/pbi fire curtains with the station label affixed to it.

[norodnik]

I know it's not exactly an O2 bottle, but for those of you not well versed in either physics or comprehension of explosive forces, here is a short video of a well understood substance when it decides it wants to leave the bottle:

YouTube - Dangerous Cole (http://www.youtube.com/watch?v=l_2-8whcDB8)

I am sure you can use a little imagination to understand the possible cause of the hole!

[Tweetair]

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?