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Probe Reveals Oxy Bottle Burst On QF Flight  
User currently offlineStealth777 From United States of America, joined Feb 2006, 375 posts, RR: 0
Posted (6 years 1 month 3 weeks 4 days 6 hours ago) and read 6166 times:

Did a search but didnt find anything but a report that is coming out on Friday investigators found out it was an oxygen bottle that caused the hole in the QF 744 that had to make the emergency landing in MNL in july.

Link to the article:

http://news.yahoo.com/s/ap/20080829/ap_on_re_au_an/australia_qantas

24 replies: All unread, jump to last
 
User currently offlineChrisrad From Australia, joined Dec 2000, 1071 posts, RR: 8
Reply 1, posted (6 years 1 month 3 weeks 4 days 6 hours ago) and read 6157 times:

Here is the link to the actual report
http://www.atsb.gov.au/publications/...2008/AAIR/pdf/AO2008053_Prelim.pdf



Welcome aboard Malaysia Airlines! Winner of Best Cabin Staff 2001,2002,2003,2004,2007,2009,2012
User currently offlineSydscott From Australia, joined Oct 2003, 3123 posts, RR: 20
Reply 2, posted (6 years 1 month 3 weeks 4 days 5 hours ago) and read 6032 times:



Quoting Chrisrad (Reply 1):
Here is the link to the actual report

Still no conclusions as to why the oxygen bottle burst though. There's obviously quite a bit more work going on there to determine theories and causes of it.


User currently offlineScrubbsYWG From Canada, joined Mar 2007, 1495 posts, RR: 0
Reply 3, posted (6 years 1 month 3 weeks 4 days 5 hours ago) and read 5986 times:

some very good pictures in that paper.

It looks now that we must wait to see if they can determine what caused the bottle to fail.


User currently offlineAviators99 From United States of America, joined May 2008, 455 posts, RR: 0
Reply 4, posted (6 years 1 month 3 weeks 4 days 5 hours ago) and read 5984 times:

I hadn't heard that the canister actually entered the passenger cabin before exiting the aircraft. It's really lucky that everyone survived this thing.

User currently offlineZkpilot From New Zealand, joined Mar 2006, 4840 posts, RR: 9
Reply 5, posted (6 years 1 month 3 weeks 4 days 4 hours ago) and read 5926 times:



Quoting Sydscott (Reply 2):
Still no conclusions as to why the oxygen bottle burst though. There's obviously quite a bit more work going on there to determine theories and causes of it.

Yes with some of the more likely possibilites being: a) rough handling by baggage loaders,
b) corrosion on the cylinder/head, c) something knocking the cylinder pre-flight/during flight, d) some other kind of failure of the cylinder (fatigue?).



56 types. 38 countries. 24 airlines.
User currently offlinePhilSquares From , joined Dec 1969, posts, RR:
Reply 6, posted (6 years 1 month 3 weeks 4 days 3 hours ago) and read 5868 times:



Quoting Zkpilot (Reply 5):
Yes with some of the more likely possibilites being: a) rough handling by baggage loaders,
b) corrosion on the cylinder/head, c) something knocking the cylinder pre-flight/during flight, d) some other kind of failure of the cylinder (fatigue?).

The leading theory is an AD that called for a inspection of the retaining brackets. The retaining brackets came loose and aircraft vibration caused the bottle to separate at the cylinder head.


User currently offlineIkramerica From United States of America, joined May 2005, 21544 posts, RR: 59
Reply 7, posted (6 years 1 month 3 weeks 4 days 3 hours ago) and read 5866 times:



Quoting PhilSquares (Reply 6):
The leading theory is an AD that called for a inspection of the retaining brackets. The retaining brackets came loose and aircraft vibration caused the bottle to separate at the cylinder head.

So leading theory is yet another QF maintenance gaff? Or am I reading that wrong?



Of all the things to worry about... the Wookie has no pants.
User currently offlineSydscott From Australia, joined Oct 2003, 3123 posts, RR: 20
Reply 8, posted (6 years 1 month 3 weeks 4 days 1 hour ago) and read 5704 times:



Quoting PhilSquares (Reply 6):
The leading theory is an AD that called for a inspection of the retaining brackets. The retaining brackets came loose and aircraft vibration caused the bottle to separate at the cylinder head.

But if it was a maintenance issue surely other bottle's on this aircraft, and on other aircraft, would have exhibited some sort of damage/defect from this? (I'm by no means a technical expert here!) Or is the theory that this one bracket somehow slipped through the system without proper checking?


User currently offlinePhilSquares From , joined Dec 1969, posts, RR:
Reply 9, posted (6 years 1 month 3 weeks 4 days 1 hour ago) and read 5688 times:



Quoting Sydscott (Reply 8):
But if it was a maintenance issue surely other bottle's on this aircraft, and on other aircraft, would have exhibited some sort of damage/defect from this? (I'm by no means a technical expert here!) Or is the theory that this one bracket somehow slipped through the system without proper checking?

Here's the AD AD.nsf/0/64e479c5774b841786257433004f6434/$FILE/2006-12-10%20R1.pdf" target=_blank>http://rgl.faa.gov/Regulatory_and_Gu...004f6434/$FILE/2006-12-10%20R1.pdf


User currently offlineLTBEWR From United States of America, joined Jan 2004, 13138 posts, RR: 15
Reply 10, posted (6 years 1 month 3 weeks 3 days 21 hours ago) and read 5495 times:

I just read the ATSB preliminary report from the above link. Very well done, answers some of our preliminary questions as well as understaning how this incident happened as well as how the O2 tanks are located and mounted (something I never knew before). Let us hope further investigation, as they are supposed to do, will help figure out what happened and to reduce the rare risk of such events in the future.

User currently offlineA10WARTHOG From United States of America, joined Jul 2004, 325 posts, RR: 0
Reply 11, posted (6 years 1 month 3 weeks 3 days 18 hours ago) and read 5325 times:



Quoting Ikramerica (Reply 7):
So leading theory is yet another QF maintenance gaff? Or am I reading that wrong?

AD can often be limited to P/N installed, Serial number of the part installed, manufacturing dates, serial number of the aircraft, etc. If the plane falls out of the range of the AD then you are go to go. I believe this is what QF has said.

Maybe there was a screw up on there end or maybe the AD needs to be widen.


User currently offline2175301 From United States of America, joined May 2007, 1074 posts, RR: 0
Reply 12, posted (6 years 1 month 3 weeks 3 days 18 hours ago) and read 5234 times:



Quoting PhilSquares (Reply 6):
The leading theory is an AD that called for a inspection of the retaining brackets. The retaining brackets came loose and aircraft vibration caused the bottle to separate at the cylinder head.

I disagree with that theory that the bottle separated at the cylinder head.

The failure as characterized is something like the bottom blowing off the bottle, not the head. A significant portion of the bottle (at least a full diameter totally round portion) was propelled upwards, and the investigators so far believe it to have been a substantial portion of the bottle. That is what would happen if the bottom - or a lower section of the bottle blew off. If the valve or the head blew off then the bottle would have been propelled down, and only the head would have been propelled upwards. The head alone would not have created the diameter of the damage found.


What is the most likely place for a bottle to fail - at the welds. The vast majority of pressure vessel failures in the pressure vessel industry are weld related failures. It is very rare for the base metal to fail in a crack like mode (although you can erode or corrode a hole). It is quite possible, with many documented cases, for a weld defect to start a crack that propagates along the weld, and once a crack reaches critical lengh it propagates at the speed of sound in the material.

Another common failure mode is from induced stresses at a rolled or formed transition. Some pressure bottles have roll formed ends (to minimize welding). That transition point from straight side to the start of the curve is a prime area for an issue if not done correctly. Also, if their is a sizable material defect at that point - and then it reached a critical size - it is likely that the crack would propagate around the cylinder at the roll transition (circumferential cracking). I have some marvelous pictures at work of several forms of circumferential cracking in heat exchangers.


User currently offlineIkramerica From United States of America, joined May 2005, 21544 posts, RR: 59
Reply 13, posted (6 years 1 month 3 weeks 3 days 17 hours ago) and read 5188 times:



Quoting A10WARTHOG (Reply 11):
Maybe there was a screw up on there end or maybe the AD needs to be widen.


Gotcha. Thanks for the clarification.  Smile



Of all the things to worry about... the Wookie has no pants.
User currently offlineHAWK21M From India, joined Jan 2001, 31684 posts, RR: 56
Reply 14, posted (6 years 1 month 3 weeks 3 days 17 hours ago) and read 5146 times:

Just got that link to the preliminary report vide Email.Need to go through it in detail.
Glad the report is out.
regds
MEL



Think of the brighter side!
User currently offlineOkie From United States of America, joined Jul 2003, 3101 posts, RR: 3
Reply 15, posted (6 years 1 month 3 weeks 3 days 12 hours ago) and read 4316 times:

Just read the report.

With the loss of the cylinder it is going to make it tough other than assumptions as to what caused the cylinder to fail.


Then after reading the report a few neurons start slamming together and make you go Hmmm.... what if a cylinder failed on TWA 800.  stirthepot 

Okie


User currently offlineIkramerica From United States of America, joined May 2005, 21544 posts, RR: 59
Reply 16, posted (6 years 1 month 3 weeks 3 days 12 hours ago) and read 4042 times:



Quoting Okie (Reply 15):
Then after reading the report a few neurons start slamming together and make you go Hmmm.... what if a cylinder failed on TWA 800.

It didn't though. So what's the point of speculating?

Exploding oxygen cylinders are different than exploding fuel. Different kind of explosions entirely...



Of all the things to worry about... the Wookie has no pants.
User currently offlineWithaK From Australia, joined Apr 2007, 255 posts, RR: 0
Reply 17, posted (6 years 1 month 3 weeks 3 days 11 hours ago) and read 3820 times:

It is absolutely amazing that that oxygen bottle didn't hit anyone. It seems like the bottle exited the cabin through the same hole it entered. Then again that's not all that surprising given the amount of air rushing though that hole. Without the offending bottle I fear that finding out the exact cause of this failure will not be known particularly if the bottle itself failed.

Kris


User currently offlineAviators99 From United States of America, joined May 2008, 455 posts, RR: 0
Reply 18, posted (6 years 1 month 3 weeks 3 days 7 hours ago) and read 2985 times:



Quoting Ikramerica (Reply 16):
It didn't though. So what's the point of speculating?

Exploding oxygen cylinders are different than exploding fuel. Different kind of explosions entirely...

Perhaps he meant that a ballistic O2 bottle could create a spark near the fuel tank?


User currently offlineIkramerica From United States of America, joined May 2005, 21544 posts, RR: 59
Reply 19, posted (6 years 1 month 3 weeks 3 days 7 hours ago) and read 2896 times:



Quoting Aviators99 (Reply 18):
Perhaps he meant that a ballistic O2 bottle could create a spark near the fuel tank?

Not sure how this is any more likely than a shorted/frayed wire doing so.



Of all the things to worry about... the Wookie has no pants.
User currently offlinePRFLYER From United States of America, joined Feb 2008, 308 posts, RR: 0
Reply 20, posted (6 years 1 month 3 weeks 3 days 6 hours ago) and read 2765 times:

Where is this QF 744 now? Where is it being repaired?

User currently offlineOkie From United States of America, joined Jul 2003, 3101 posts, RR: 3
Reply 21, posted (6 years 1 month 3 weeks 3 days 6 hours ago) and read 2728 times:



Quoting Aviators99 (Reply 18):
Perhaps he meant that a ballistic O2 bottle could create a spark near the fuel tank?

Actually, I was thinking
1. Penetrated the tank creating a spark and also introducing O2 to the fuel air mix as well.
or
2. In the QF incident wiring bundles were damaged which could introduce a high voltage spark into the low voltage wiring harness for fuel sensors.

The cylinder in the QF incident seemed to have considerable energy to go through a floor, break a door operating mechanism, damage wiring bundles, through the overhead panel and back out the hole as well as damage the fuselage and fuselage fairing. (that is a lot of energy)

I do not have any idea if such a possibility existed therefore  stirthepot  , however the center fuel tank is in close proximity of the O2 cylinders as well as wiring bundles.

Okie


User currently offlineHAWK21M From India, joined Jan 2001, 31684 posts, RR: 56
Reply 22, posted (6 years 1 month 3 weeks 2 days 22 hours ago) and read 2584 times:

For a type flying for so many years this being a 1st similiar incident is surprising too.
regds
MEL



Think of the brighter side!
User currently offlineBAflyer From United Kingdom, joined Mar 2005, 72 posts, RR: 0
Reply 23, posted (6 years 1 month 3 weeks 2 days 21 hours ago) and read 2520 times:

Surely this has to go down as one of the most ironic incidents of all time.

The very device that is fitted to the aircraft to save your life in the event of a depressurisation actually causes the depressurisation.

Has any other incident / accident been caused by faulty safety equipment?



Most frustrating part of being an atheist - Never being able to say "Told you so".
User currently offlinePRFLYER From United States of America, joined Feb 2008, 308 posts, RR: 0
Reply 24, posted (6 years 1 month 2 weeks 4 days 20 hours ago) and read 2219 times:



Quoting PRFLYER (Reply 20):
Where is this QF 744 now? Where is it being repaired?

To answer my own question, someone posted a picture of this A/C on another website. It is still in Manila being repaired by Boeing assisted by LTP.

http://img.photobucket.com/albums/v48/markpaul/IMG_0047.jpg


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