Qantas 744 Depressurisation
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Apparently the flights captain, John Bartels wife had this to say about it on another web site as OZWITCH
Commwealth flying | Neptunus Lex
"You might not recall that my husband was ex-RAN A4. He now flies 747-400. He had the explosive decompression yesterday.
Fun day!
I can give your readers some facts that are solid:
No engines were shut down.
Aeroplane’s controls were unaffected.
Some computer functions and electrics were affected - all 3 ILS shut down and the Capt’s FMC. Antiskid warning came on.
The R2 door alarm activated.
Capt inititated controlled descent from 29K to 10K, which took about 4 mins. Mayday was called (John never ever thought he would have to declare a mayday in his entire career!)
After levelling off, fuel dump of 50 tons was commenced, and plane landed afterwards normally, but used all available runway. Engine #3 was shut down first, then 3 others after and plane was towed to terminal. Passengers disembarked normally via aerobridge.
John praised crew and passengers, who all rose to the occasion.
I have a few pics I can share if you’d like. Let me know, and if any other q’s
Ozwitch"
Commwealth flying | Neptunus Lex
"You might not recall that my husband was ex-RAN A4. He now flies 747-400. He had the explosive decompression yesterday.
Fun day!
I can give your readers some facts that are solid:
No engines were shut down.
Aeroplane’s controls were unaffected.
Some computer functions and electrics were affected - all 3 ILS shut down and the Capt’s FMC. Antiskid warning came on.
The R2 door alarm activated.
Capt inititated controlled descent from 29K to 10K, which took about 4 mins. Mayday was called (John never ever thought he would have to declare a mayday in his entire career!)
After levelling off, fuel dump of 50 tons was commenced, and plane landed afterwards normally, but used all available runway. Engine #3 was shut down first, then 3 others after and plane was towed to terminal. Passengers disembarked normally via aerobridge.
John praised crew and passengers, who all rose to the occasion.
I have a few pics I can share if you’d like. Let me know, and if any other q’s
Ozwitch"
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What about the 2 portable oxy bottles located just fwd of door 2r at the flight attendants seat ? They are in the usually mounted in a box just where the damage in the cabin sidewall was.
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Does the B744 Configuration Deviation List allow aircraft operation without the wing-to-fuselage fairing? If so, we can totally discount the part of the fairing in this incident and concentrate on what made the hole in the pressure hull.
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Does the B744 Configuration Deviation List allow aircraft operation without the wing-to-fuselage fairing? If so, we can totally discount the part of the fairing in this incident and concentrate on what made the hole in the pressure hull.
Resident insomniac
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Article from: The Australian
July 28, 2008 12:01am
QANTAS last night began inspecting oxygen bottles on its Boeing 747-400s after investigators found cylinder fragments embedded in luggage and the cargo hold ceiling of the jumbo jet involved in Friday's mid-air explosion near The Philippines.
While the Australian Transport Safety Bureau was refusing to rule out causes such as structural fatigue for a gaping hole in the Boeing 747-400, aviation sources said oxygen bottle failure was now at the top of investigators' list, The Australian reports.
Aviation sources said the force of the explosion near the base of the aircraft's right wing and underneath a door pushed up the passenger cabin floor as it tore through the metal hull.
They said there were two oxygen bottles in the area near the hole, and a failure was unprecedented.
ATSB spokesman Neville Blyth confirmed last night that a cylinder providing back-up oxygen was missing, but said it was too early to say whether this caused the explosion.
QANTAS last night began inspecting oxygen bottles on its Boeing 747-400s after investigators found cylinder fragments embedded in luggage and the cargo hold ceiling of the jumbo jet involved in Friday's mid-air explosion near The Philippines.
While the Australian Transport Safety Bureau was refusing to rule out causes such as structural fatigue for a gaping hole in the Boeing 747-400, aviation sources said oxygen bottle failure was now at the top of investigators' list, The Australian reports.
Aviation sources said the force of the explosion near the base of the aircraft's right wing and underneath a door pushed up the passenger cabin floor as it tore through the metal hull.
They said there were two oxygen bottles in the area near the hole, and a failure was unprecedented.
ATSB spokesman Neville Blyth confirmed last night that a cylinder providing back-up oxygen was missing, but said it was too early to say whether this caused the explosion.
Igniting Oxygen
For interest. Early 707, supplementary oxygen bottle stowed on Flt. Deck rear wall near Flt. Eng. panel. Flt. Eng. hung his uniform cap on bottle, hat had plastic square inside to prevent hair grease staining the fabric which of course became greasy. O2 bottle valve had slight leak, hat caught fire, fortunately with no serious consequences. Doesn't help present problem but shall we wait for some FACTS now ? Thank you.
Warning Toxic!
Disgusted of Tunbridge
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It's just a cacophany now, isn't it? Suddenly 100 amateur self-appointed accident investigators crawling out of the woodwork, leading the investigation. Horrifying. At least the 'struck by atmospheric re-entering Slazenger golf club' theory is now excluded! I never knew anybody with a keyboard could come across suddenly as a metallurgist/stress fracture expert. And we are supposed to read their 'analysis'?
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Selfloading said:
Naaaaa. Had lots of fairings come off. They're plastic, composite, honeycombe, or thin sheetmetal affairs (or combinations.) Think flimsy. Think light. Think designed by Mr boeing not to be anchored into important structure without the fastner hardware designed to yield or strip free before it would be able to rip apart something as stout as a Frame or longitudinal stringer or spar.
What most SLF don't realize is that Goldfinger and Airport 77 are fiction. A small hole in the skin (if it doesn't break a crossbeam) probably isn't going to cause a rapid decompression. Conversely the 747 is not a boat; it is not water tight. In it's normal state, it is absolutely full of holes, leaks, seals hissing.....
Stick your hand down near a galley door. Chances are you'll feel it. Cold from the venturi effect of air escaping.
Sure, if it came loose, that fairing would flap around and maybe cause some little holes in the skin or screw up something else down stream when it disintegrated or possibly even go through an engine if you're real unlucky, but I can't see it causing that kind of damage.
IMHO, this is either a structural failure of the pressure vessel which took with it everything fastened to either side of the wall (O2 tanks and fairing)
- OR -
a structural failure of an oxygen tank that destroyed the integrity of the frame latticework.
Always suspect problems when engineers realize that the area has been previously repaired (as in this case.)
I give you as a case study, JAL Flight 123. The engineer who approved the repair committed suicide when it became obvious it was designed improperly.
Japan Airlines Flight 123 - Wikipedia, the free encyclopedia
Also there's this:
Safety Promotion Center - Wikipedia, the free encyclopedia
Section 41 and section 43 mods addressed known areas of weakness in the 747 design. The drawing supplied to us earlier in this thread is said by the poster to come from section 42.
These are all just my opinions; I am not an expert.
pac
Dunno, is it not possible the the fairing did not come away in one piece but broke up, and in doing so punctured the pressure hull?
What most SLF don't realize is that Goldfinger and Airport 77 are fiction. A small hole in the skin (if it doesn't break a crossbeam) probably isn't going to cause a rapid decompression. Conversely the 747 is not a boat; it is not water tight. In it's normal state, it is absolutely full of holes, leaks, seals hissing.....
Stick your hand down near a galley door. Chances are you'll feel it. Cold from the venturi effect of air escaping.
Sure, if it came loose, that fairing would flap around and maybe cause some little holes in the skin or screw up something else down stream when it disintegrated or possibly even go through an engine if you're real unlucky, but I can't see it causing that kind of damage.
IMHO, this is either a structural failure of the pressure vessel which took with it everything fastened to either side of the wall (O2 tanks and fairing)
- OR -
a structural failure of an oxygen tank that destroyed the integrity of the frame latticework.
Always suspect problems when engineers realize that the area has been previously repaired (as in this case.)
I give you as a case study, JAL Flight 123. The engineer who approved the repair committed suicide when it became obvious it was designed improperly.
Japan Airlines Flight 123 - Wikipedia, the free encyclopedia
Cause
The official cause of the crash according to the report published by the Japanese Aircraft and Railway Accidents Investigation Commission is as follows:
The aircraft was involved in a tailstrike incident at Osaka International Airport on June 2, 1978, which damaged the aircraft's rear pressure bulkhead.
The subsequent repair performed by the engineers was flawed. Boeing's procedures called for a doubler plate with two rows of rivets to cover up the damaged bulkhead, but the engineers fixing the aircraft used two doubler plates with only one row of rivets. This reduced the part's resistance to metal fatigue by 70%. According to the FAA, the one "doubler plate" which was specified for the job, (the FAA calls it a "splice plate" - essentially a patch), was cut into two pieces parallel to the stress crack it was intended to reinforce, "to make it fit".[10] This negated the effectiveness of one of the two rows of rivets. During the investigation Boeing calculated that this incorrect installation would fail after approximately 10,000 pressurizations; the aircraft accomplished 12,319 take-offs between the installation of the new plate and the final accident.
When the bulkhead gave way, the resulting explosive decompression ruptured the lines of all four hydraulic systems. With the aircraft's control surfaces disabled, the aircraft became uncontrollable.
[edit]Aftermath
The Japanese public's confidence in Japan Airlines took a dramatic downturn in the wake of the disaster, with passenger numbers on domestic routes dropping by one-third. Rumours persisted that Boeing had admitted fault to cover up shortcomings in the airline's inspection procedures and thus protect the reputation of a major customer.[4] In the months after the crash, domestic traffic decreased by as much as 25%. In 1986, for the first time in one decade, fewer passengers boarded JAL's overseas flights during New Years than the previous year.[11]
Without admitting liability, JAL paid 780 million yen to the victims' relatives in the form of "condolence money". Its president, Yasumoto Takagi, resigned, while a maintenance manager working for the company at Haneda committed suicide to "apologize" for the accident.[4]
The official cause of the crash according to the report published by the Japanese Aircraft and Railway Accidents Investigation Commission is as follows:
The aircraft was involved in a tailstrike incident at Osaka International Airport on June 2, 1978, which damaged the aircraft's rear pressure bulkhead.
The subsequent repair performed by the engineers was flawed. Boeing's procedures called for a doubler plate with two rows of rivets to cover up the damaged bulkhead, but the engineers fixing the aircraft used two doubler plates with only one row of rivets. This reduced the part's resistance to metal fatigue by 70%. According to the FAA, the one "doubler plate" which was specified for the job, (the FAA calls it a "splice plate" - essentially a patch), was cut into two pieces parallel to the stress crack it was intended to reinforce, "to make it fit".[10] This negated the effectiveness of one of the two rows of rivets. During the investigation Boeing calculated that this incorrect installation would fail after approximately 10,000 pressurizations; the aircraft accomplished 12,319 take-offs between the installation of the new plate and the final accident.
When the bulkhead gave way, the resulting explosive decompression ruptured the lines of all four hydraulic systems. With the aircraft's control surfaces disabled, the aircraft became uncontrollable.
[edit]Aftermath
The Japanese public's confidence in Japan Airlines took a dramatic downturn in the wake of the disaster, with passenger numbers on domestic routes dropping by one-third. Rumours persisted that Boeing had admitted fault to cover up shortcomings in the airline's inspection procedures and thus protect the reputation of a major customer.[4] In the months after the crash, domestic traffic decreased by as much as 25%. In 1986, for the first time in one decade, fewer passengers boarded JAL's overseas flights during New Years than the previous year.[11]
Without admitting liability, JAL paid 780 million yen to the victims' relatives in the form of "condolence money". Its president, Yasumoto Takagi, resigned, while a maintenance manager working for the company at Haneda committed suicide to "apologize" for the accident.[4]
Safety Promotion Center - Wikipedia, the free encyclopedia
Section 41 and section 43 mods addressed known areas of weakness in the 747 design. The drawing supplied to us earlier in this thread is said by the poster to come from section 42.
These are all just my opinions; I am not an expert.
pac
Last edited by pacplyer; 28th Jul 2008 at 10:36. Reason: spelling, disclaimer, better verb-age
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The informed discussion on this is taking place in the Dunnunda forum. Pieces of the pax oxy bottle have been found inside the main cabin. They entered the main cabin via the hole that pieces of the bottle punched through the floor at R2. The bottle was apparently six months old.
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The silver bullet?
According to an update on MSNBC - fragments have been found from a compressed air/oxy tank, specifically the valve, which makes the tank look increasingly like the prime suspect.
Expect the fax machine in your local maintenance office to start churning soon.
Expect the fax machine in your local maintenance office to start churning soon.
Cunning Artificer
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The informed discussion on this is taking place in the Dunnunda forum. Pieces of the pax oxy bottle have been found inside the main cabin. They entered the main cabin via the hole that pieces of the bottle punched through the floor at R2. The bottle was apparently six months old.
Now all we need to know is what initiated the first ever recorded occurrence of an aircraft oxygen cylinder exploding in flight. I'm jiggered if I can think of any initiators off-hand. We can certainly discount maniac firearm owners who want to see "what happens if" like the chaps on You Tube.
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Attn. Nov71
‘O2 escaping at high pressure even from a slow leak, can create high temps (adiabatic ) The presence of a small amount of oil/grease can cause ignition’
Sorry, but you're wrong on this point. Adiabatic expansion (and compression) is a system that applies to confined gases that remain confined throughout the process. Escaping gas is not an adiabatic system. Adiabatic compression makes the gas hot, with no loss of heat to the surroundings; adiabatic expansion sees the gas cooling, but again with no heat transfer.
What we have here is the question of escaping gas, which has nothing to do with an adiabatic system. When you release a CO2 fire extinguisher — the cannister and contents being at ambient temp — the gas that emerges is very cold. This is what happens when any compressed gas is allowed to expand rapidly. The gas absorbs a great deal of heat from the surroundings. The warnings on BOC cylinders are about the danger of combustion in the presence of O2.
Sorry, but you're wrong on this point. Adiabatic expansion (and compression) is a system that applies to confined gases that remain confined throughout the process. Escaping gas is not an adiabatic system. Adiabatic compression makes the gas hot, with no loss of heat to the surroundings; adiabatic expansion sees the gas cooling, but again with no heat transfer.
What we have here is the question of escaping gas, which has nothing to do with an adiabatic system. When you release a CO2 fire extinguisher — the cannister and contents being at ambient temp — the gas that emerges is very cold. This is what happens when any compressed gas is allowed to expand rapidly. The gas absorbs a great deal of heat from the surroundings. The warnings on BOC cylinders are about the danger of combustion in the presence of O2.
Last edited by Vertiginous; 28th Jul 2008 at 13:20.
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Attn. Iomapaseo
‘So why did the lower sections all seem to separate along a rivet line, while the rest was random tearing?’
It takes less force to separate a riveted lap seam than to rip a panel. In other words, if a panel is ripped, this was achieved with a large amount of energy.
It takes less force to separate a riveted lap seam than to rip a panel. In other words, if a panel is ripped, this was achieved with a large amount of energy.