Qantas 744 Depressurisation
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Good point loma, Thanks
I've changed it to "hypothetically" and "possible black charing."
But that is the 747 freighter procedure for long range fire. Loose the cabin pressure by driving the outflow valves full open; which starves the fire of oxygen. In our leak/bang theoretical, it's a flash fire that gets extinguished almost immediately. Fire detection may not come into play as they are optical sensors that look for obscuration of the internal light source much like your fire detector at home. Dust raised during loading sometimes sets these things off but not sure about a flash fire? Usually smoke would have to be present for a number of seconds to make them decide it's for real. If the air volume gets evacuated in seconds?
(Cornflakes university is one of the better mail order degrees by the way; highly respected
)
I've changed it to "hypothetically" and "possible black charing."
But that is the 747 freighter procedure for long range fire. Loose the cabin pressure by driving the outflow valves full open; which starves the fire of oxygen. In our leak/bang theoretical, it's a flash fire that gets extinguished almost immediately. Fire detection may not come into play as they are optical sensors that look for obscuration of the internal light source much like your fire detector at home. Dust raised during loading sometimes sets these things off but not sure about a flash fire? Usually smoke would have to be present for a number of seconds to make them decide it's for real. If the air volume gets evacuated in seconds?
(Cornflakes university is one of the better mail order degrees by the way; highly respected
)
Last edited by pacplyer; 30th Jul 2008 at 04:03. Reason: better speculation
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If the failure was at the cylinder neck/valve assembly, then the equal/opposite reaction may have caused the cylinder to pivot at the upper strap mount, forcing the bottom towards the hull and either rupturing or penetrating the hull.
Last edited by Machaca; 30th Jul 2008 at 03:51. Reason: clarification
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There's actually quite a lot of stuff that will spontaneously combust in the presence of pure oxygen (hence the "do not grease" instruction for oxygen pipe and valve gear), so it's quite possible that a small leak and some contaminant on the pipe (maintenance guy with slightly greasy hands handling the pipe, perhaps) could generate that if a leak was blowing oxygen along the pipe from its valve connection. Low temperature would tend to inhibit things from starting, but if it started on the ground it could generate enough local heat to be self-sustaining as the environment cooled off.
I'm not sure how any of that would cause the bottle to rupture though, so it might be an after-effect rather than a cause. (OK, I can think of a way but the probability is only marginally greater than the golf-club-from-outer-space theory that appeared earlier in the thread)
I'm not sure how any of that would cause the bottle to rupture though, so it might be an after-effect rather than a cause. (OK, I can think of a way but the probability is only marginally greater than the golf-club-from-outer-space theory that appeared earlier in the thread)
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Buster
As outlined by pacplyer,the fire detection system works on optical obscuration of sensors by combusted particles. The particles/cabin air is drawn through a chamber via cabin differential pressure. If there is no differential pressure such as in a decompression, there is no sampling and no fire alarm.
Wunwing
As outlined by pacplyer,the fire detection system works on optical obscuration of sensors by combusted particles. The particles/cabin air is drawn through a chamber via cabin differential pressure. If there is no differential pressure such as in a decompression, there is no sampling and no fire alarm.
Wunwing
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Hot Off The Press.
Some FACTS emerging...
4000fpm??? Hardly a 'plunge'!
O2 masks not deploying?? NOT!
http://www.atsb.gov.au/newsroom/2008/release/2008_28.aspx
4000fpm??? Hardly a 'plunge'!
O2 masks not deploying?? NOT!
http://www.atsb.gov.au/newsroom/2008/release/2008_28.aspx
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Further ATSB Press Release
MEDIA RELEASE
2008/28
Investigation into Boeing 747- 400 depressurisation and diversion to Manila, Philippines
30 July 2008
Introduction
As you are aware the ATSB is leading this safety investigation with the assistance of a number of other organisations and agencies, including the Civil Aviation Authority of the Philippines, the National Transportation Safety Board and the Federal Aviation Administration of the USA, the Civil Aviation Safety Authority of Australia, Qantas and Boeing.
Flight Data Recorder
The data from the flight data recorder has been recovered and downloaded. Initial analysis of the data indicates that the aircraft decent from the decompression event at 29,000 feet to the altitude of 10,000 feet, where no masks are required, took about five and half minutes, with an average descent rate of about 4,000 fpm. The ATSB is still verifying and analysing the data on the recorder.
Door
The ATSB can confirm that it appears that part of an oxygen cylinder and valve entered the passenger cabin and impacted the number 2 right door frame handle, thereby moving the handle part way towards the open position. However, the door handle mechanism has been sheared as it is designed to do if an attempt is made to open the door in flight, so the position of the door handle is not representative of the position of the door lock mechanism or the security of the door. The investigation team have confirmed that the door latches were still engaged. Additionally the door is of the plug-type that first needs to be pulled into the cabin, rotated 90 degrees then pushed out to open. So there was never any danger of the door opening.
Cabin Masks
The investigation team have surveyed the passenger cabin including the oxygen masks. The team found that most of the oxygen masks had deployed correctly from the passenger modules and had been pulled to activate the flow of oxygen to the mask. According to the airline, there were 346 passengers on board. Inspection by the ATSB shows that 484 masks had deployed, that is, dropped from the ceiling. Of those, 418 had been activated by pulling on the mask to activate the flow of oxygen. Only a small number of masks appeared to have had the elastic retaining strap adjusted by the passengers. It also appears that a small number of masks did not deploy from the passenger modules. Investigations into this aspect of the accident are continuing.
Interviews are continuing with the cabin crew in relation to this issue. Additionally, the ATSB is preparing a passenger survey that will be sent to all passengers to gather information about their experience of the event. The ATSB also plans to interview those passengers that encountered specific problems either with the masks or the decompression event.
Oxygen System
The investigation team is still examining the oxygen system, including liaising with the manufacturer to determine if the flow of oxygen was adequate for the five and a half minute descent to 10,000 feet, where the masks were no longer required.
ILS
The team have confirmed that the aircrafts three Instrument Landing Systems (ILS) and the anti-skid system were not available for the arrival and landing at Manila. However, evidence to date indicates that all the aircrafts main systems, including engines and hydraulics were functioning normally. The approach to Manila airport was conducted in visual conditions. It should be noted that other pilot navigation instruments (VOR and NDB) were still available to the crew should the conditions not have been visual. Additionally, Air Traffic Control could have provided radar assistance if the crew had required it.
Flight Crew
From the evidence gathered to date it appears that the flight crew have responded to and managed the emergency situation extremely well. It is apparent that they followed the procedures they have trained for in simulators, which ensured the best possible outcome for the aircraft, the passengers and crew.
Notify ATSB
A reminder that the ATSB requests that any passengers that experienced issues during the flight, or those who photographed or videoed the incident, contacts us via email [email protected] , telephone: 1800 020 616, or facsimile 02 6247 3117.
The investigation will need time to review and analyse the evidence collected to date and to plan and undertake further evidence gathering and analysis. It is difficult to say how long an investigation such as this will take. However, a preliminary factual report will be released by the ATSB within about 30 days and, should the need for urgent safety action by any agency be identified, the ATSB will immediately notify the relevant agencies who are best placed to address the issue. At this point, unless there is any significant development in the investigation, further media conferences are not anticipated and further information will be released as part of the ATSBs preliminary report.
Media Contact: George Nadal during business hours & after hours duty officer: 1800 020 616
MEDIA RELEASE : 30 July 2008 - Investigation into Boeing 747- 400 depressurisation and diversion to Manila, Philippines
2008/28
Investigation into Boeing 747- 400 depressurisation and diversion to Manila, Philippines
30 July 2008
Introduction
As you are aware the ATSB is leading this safety investigation with the assistance of a number of other organisations and agencies, including the Civil Aviation Authority of the Philippines, the National Transportation Safety Board and the Federal Aviation Administration of the USA, the Civil Aviation Safety Authority of Australia, Qantas and Boeing.
Flight Data Recorder
The data from the flight data recorder has been recovered and downloaded. Initial analysis of the data indicates that the aircraft decent from the decompression event at 29,000 feet to the altitude of 10,000 feet, where no masks are required, took about five and half minutes, with an average descent rate of about 4,000 fpm. The ATSB is still verifying and analysing the data on the recorder.
Door
The ATSB can confirm that it appears that part of an oxygen cylinder and valve entered the passenger cabin and impacted the number 2 right door frame handle, thereby moving the handle part way towards the open position. However, the door handle mechanism has been sheared as it is designed to do if an attempt is made to open the door in flight, so the position of the door handle is not representative of the position of the door lock mechanism or the security of the door. The investigation team have confirmed that the door latches were still engaged. Additionally the door is of the plug-type that first needs to be pulled into the cabin, rotated 90 degrees then pushed out to open. So there was never any danger of the door opening.
Cabin Masks
The investigation team have surveyed the passenger cabin including the oxygen masks. The team found that most of the oxygen masks had deployed correctly from the passenger modules and had been pulled to activate the flow of oxygen to the mask. According to the airline, there were 346 passengers on board. Inspection by the ATSB shows that 484 masks had deployed, that is, dropped from the ceiling. Of those, 418 had been activated by pulling on the mask to activate the flow of oxygen. Only a small number of masks appeared to have had the elastic retaining strap adjusted by the passengers. It also appears that a small number of masks did not deploy from the passenger modules. Investigations into this aspect of the accident are continuing.
Interviews are continuing with the cabin crew in relation to this issue. Additionally, the ATSB is preparing a passenger survey that will be sent to all passengers to gather information about their experience of the event. The ATSB also plans to interview those passengers that encountered specific problems either with the masks or the decompression event.
Oxygen System
The investigation team is still examining the oxygen system, including liaising with the manufacturer to determine if the flow of oxygen was adequate for the five and a half minute descent to 10,000 feet, where the masks were no longer required.
ILS
The team have confirmed that the aircrafts three Instrument Landing Systems (ILS) and the anti-skid system were not available for the arrival and landing at Manila. However, evidence to date indicates that all the aircrafts main systems, including engines and hydraulics were functioning normally. The approach to Manila airport was conducted in visual conditions. It should be noted that other pilot navigation instruments (VOR and NDB) were still available to the crew should the conditions not have been visual. Additionally, Air Traffic Control could have provided radar assistance if the crew had required it.
Flight Crew
From the evidence gathered to date it appears that the flight crew have responded to and managed the emergency situation extremely well. It is apparent that they followed the procedures they have trained for in simulators, which ensured the best possible outcome for the aircraft, the passengers and crew.
Notify ATSB
A reminder that the ATSB requests that any passengers that experienced issues during the flight, or those who photographed or videoed the incident, contacts us via email [email protected] , telephone: 1800 020 616, or facsimile 02 6247 3117.
The investigation will need time to review and analyse the evidence collected to date and to plan and undertake further evidence gathering and analysis. It is difficult to say how long an investigation such as this will take. However, a preliminary factual report will be released by the ATSB within about 30 days and, should the need for urgent safety action by any agency be identified, the ATSB will immediately notify the relevant agencies who are best placed to address the issue. At this point, unless there is any significant development in the investigation, further media conferences are not anticipated and further information will be released as part of the ATSBs preliminary report.
Media Contact: George Nadal during business hours & after hours duty officer: 1800 020 616
MEDIA RELEASE : 30 July 2008 - Investigation into Boeing 747- 400 depressurisation and diversion to Manila, Philippines
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ATSB announcement
Oxygen cylinder at fault in Qantas emergency: ATSB
full story at Oxygen cylinder at fault in Qantas emergency: ATSB - ABC News (Australian Broadcasting Corporation)
full story at Oxygen cylinder at fault in Qantas emergency: ATSB - ABC News (Australian Broadcasting Corporation)
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ABC Aus Report Headed Oxygen cylinder at fault
Oxygen cylinder at fault in Qantas emergency: ATSB
Posted 41 minutes ago
Updated 21 minutes ago
Air safety investigators have confirmed an oxygen cylinder was to blame for an explosion on a Qantas 747 last week.
The jet was forced to make an emergency landing in Manila after a blast blew a hole in the fuselage.
The Australian Transport Safety Bureau's (ATSB) preliminary investigations have also found a small number of oxygen masks in the plane did not deploy.
"The team found that most of the oxygen masks had deployed correctly from the passenger modules and had been pulled to activate the flow of oxygen to the mask," the ATSB said in a statement.
"Only a small number of masks appeared to have had the elastic retaining strap adjusted by the passengers.
"It also appears that a small number of masks did not deploy from the passenger modules.
"Investigations into this aspect of the accident are continuing."
The bureau says it intends to interview Qantas cabin crew and passengers who encountered problems with their oxygen masks.
The ATSB also confirmed that the Qantas flight crew handled the situation well.
"From the evidence gathered to date it appears that the flight crew have responded to and managed the emergency situation extremely well," the statement said.
"It is apparent that they followed the procedures they have trained for in simulators, which ensured the best possible outcome for the aircraft, the
passengers and crew."
The ATSB is asking any passengers who managed to photograph or video the in flight drama to come forward.
Posted 41 minutes ago
Updated 21 minutes ago
Air safety investigators have confirmed an oxygen cylinder was to blame for an explosion on a Qantas 747 last week.
The jet was forced to make an emergency landing in Manila after a blast blew a hole in the fuselage.
The Australian Transport Safety Bureau's (ATSB) preliminary investigations have also found a small number of oxygen masks in the plane did not deploy.
"The team found that most of the oxygen masks had deployed correctly from the passenger modules and had been pulled to activate the flow of oxygen to the mask," the ATSB said in a statement.
"Only a small number of masks appeared to have had the elastic retaining strap adjusted by the passengers.
"It also appears that a small number of masks did not deploy from the passenger modules.
"Investigations into this aspect of the accident are continuing."
The bureau says it intends to interview Qantas cabin crew and passengers who encountered problems with their oxygen masks.
The ATSB also confirmed that the Qantas flight crew handled the situation well.
"From the evidence gathered to date it appears that the flight crew have responded to and managed the emergency situation extremely well," the statement said.
"It is apparent that they followed the procedures they have trained for in simulators, which ensured the best possible outcome for the aircraft, the
passengers and crew."
The ATSB is asking any passengers who managed to photograph or video the in flight drama to come forward.
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Just wondering what corrosion inhibiting compound would do in combination with, say, a tiny leak in the oxygen plumbing? I assume it's a hydrocarbon of some description.
I'm guessing it's not very reactive, however, once the compound dries.
Rgds.
NSEU
I'm guessing it's not very reactive, however, once the compound dries.
Rgds.
NSEU
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I've got some Boeshield T9 at home. I'll spray some, let it dry and then throw it on the fire. Very waxxy substance one dry, my guess is it will still go 'wooshkah' when it hits the heat.
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Fresh off the press
The Australian Transport Safety Bureau (ATSB) said today a piece of the oxygen tank entered the passenger cabin after smashing through the cabin floor and hit an emergency door handle, moving it part way into the open position.
ATSB spokesman Julian Walsh said passengers were not in danger, because the position of the handle did not mean the security of the door was at risk.
Passengers not in danger? Good thing the door handle wasn't a Pax head
The Australian Transport Safety Bureau (ATSB) said today a piece of the oxygen tank entered the passenger cabin after smashing through the cabin floor and hit an emergency door handle, moving it part way into the open position.
ATSB spokesman Julian Walsh said passengers were not in danger, because the position of the handle did not mean the security of the door was at risk.
Passengers not in danger? Good thing the door handle wasn't a Pax head
I don't own this space under my name. I should have leased it while I still could
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I've got some Boeshield T9 at home. I'll spray some, let it dry and then throw it on the fire. Very waxxy substance one dry, my guess is it will still go 'wooshkah' when it hits the heat.
Amazing how the press comments reported above mangle the well chosen words of the ATSB statement.
The ATSB has NOT said that the oxygen bottle was to blame for the decompression. All that is apparent is that one disintegrated, which leaves open that this was either a cause or consequence.
The ATSB has NOT said that passengers were not at risk from flying debris or the event per se, simply that there was no risk of the damaged door opening.
The ATSB has NOT said that the oxygen bottle was to blame for the decompression. All that is apparent is that one disintegrated, which leaves open that this was either a cause or consequence.
The ATSB has NOT said that passengers were not at risk from flying debris or the event per se, simply that there was no risk of the damaged door opening.
sua cuique voluptas
SLF Alert....
With reference to Machaca's picture on post #703, I'm amazed that there only appears to be one retaining strap near the tank neck. Given the potential for stored energy to move the cylinder mass around this pivot point (as he illustrates) is this the only mechanism used to stop it going walkies? I would have expected at least a lower cup support or a rear vertical spine plus a lower strap system.
Not exactly relevant I know but I wouldn't dream of flying a hot air balloon without two strapping systems on the flight cylinders - and my landings are (usually) not much more violent than a 747's arrival.
I only ask 'cos I'm interested.
Ripline
With reference to Machaca's picture on post #703, I'm amazed that there only appears to be one retaining strap near the tank neck. Given the potential for stored energy to move the cylinder mass around this pivot point (as he illustrates) is this the only mechanism used to stop it going walkies? I would have expected at least a lower cup support or a rear vertical spine plus a lower strap system.
Not exactly relevant I know but I wouldn't dream of flying a hot air balloon without two strapping systems on the flight cylinders - and my landings are (usually) not much more violent than a 747's arrival.
I only ask 'cos I'm interested.
Ripline
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The ATSB can confirm that it appears that part of an oxygen cylinder and valve entered the passenger cabin
It still seems very fortunate that the remaining parts of the cylinder left the hull and did not cause more damage.
No mention of any other parts of the cylinder found onboard
No mention of how much or what else got sucked out.
So was it just the top ?/neck of the cylinder that got detached and the almost intact remainder that exited?
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doorframe damage- we knew this a week ago
Shoot me down for arrogance why don't you, but on 25th July I posted the comments at base of this post.
(Original post: page 9 post number 166).
I had hoped others would debate the point I raised.But the point was ignored.
It would appear my onservations about damage thru the structure and particularly in the door frame were 100 per cent accurate - resultant not causative context of course.
Given the 36 pages of speculation the event has created, I now claim a golden b...ock award for smugness and accuracy of investigative observation. The media missed it too! Yippee. They had to wait for the ATSB to say it 6 days later...
I thank you.
EXTRACT POST 166:
"Of note is that in the internal galley/door 2 right shots, the internal trim on the forward edge of the door psot has been damaged. This may explain a possible initial cabin crew report of a door going or a main door warning light flashing on the flight deck.
Given that the interior door panel/post is showing damage, it is clear that the force of the so far unknown event did go thru the structure adn it is further evidence just how lucky QF are- and how stong Mr Boeing makes a 'plane."
Ends
(Original post: page 9 post number 166).
I had hoped others would debate the point I raised.But the point was ignored.
It would appear my onservations about damage thru the structure and particularly in the door frame were 100 per cent accurate - resultant not causative context of course.
Given the 36 pages of speculation the event has created, I now claim a golden b...ock award for smugness and accuracy of investigative observation. The media missed it too! Yippee. They had to wait for the ATSB to say it 6 days later...
I thank you.
EXTRACT POST 166:
"Of note is that in the internal galley/door 2 right shots, the internal trim on the forward edge of the door psot has been damaged. This may explain a possible initial cabin crew report of a door going or a main door warning light flashing on the flight deck.
Given that the interior door panel/post is showing damage, it is clear that the force of the so far unknown event did go thru the structure adn it is further evidence just how lucky QF are- and how stong Mr Boeing makes a 'plane."
Ends
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Apologies if this has already been mentioned, but would it not be a good idea if the cabin crew mentioned the likelihood of a rapid descent in the event of the oxygen masks being deployed during the safety demonstration, thus depriving the media of the "plummeting towards the ground" stories?