Qantas 744 Depressurisation
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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
Beneath that is the alodine ( another corrosion prevention treatment) treated skin
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NSEU said:
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?
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
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?
Last edited by pacplyer; 27th Jul 2008 at 07:53.
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Rainboe wrote:
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....
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?
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....
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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.
...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.
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Fromt The Australian newspaper: Missing oxygen cylinder (not?) in Qantas plane
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
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
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"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
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
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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.
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.
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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
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
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
About Qantas - Newsroom
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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?
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?
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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.
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.
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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
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
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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
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.
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
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.
The Reverend
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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.
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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!
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!
Last edited by BOAC; 27th Jul 2008 at 11:09.
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 ?
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Flight crew oxygen sources
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...
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Phone footage
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.
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.
Last edited by beaglecp; 27th Jul 2008 at 09:21.
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B747 300 & 400 Pax Oxy
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 quickl˙, 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.
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 quickl˙, 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.
Last edited by Little_Red_Hat; 27th Jul 2008 at 09:15. Reason: PC hiccups!
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747 O2
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!)