China Airlines B747 Crash (Merged)
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I am a bit bewildered by the absence of any indication of a structural failure or decompression on the CVR over a multi-second period.
Assuming the FDR data trace is accurate (as well as my eyesight), the first parameter for which data is lost is engine pressure ratio for the #1 engine at 07:27:55. Most other parameters are lost around 07:27:57, with pitch being the last parameter with data recorded, stopping at 07:27:58.
The CVR stops at 07:28:03. Thus, there appears to be an interval of 7 to 8 seconds between initial loss of an FDR parameter and loss of CVR data. This would seem to be adequate time for some indication of a significant decompression to have been recorded on the CVR.
As I understand it, the data cables to the CVR and FDR run along the upper left of the cabin, and the power supply for these runs along the upper right. In a progressive failure, one might still briefly have power to the CVR and FDR and no data, or vice versa.
According to AWST, the Chinese radar recorded beacon returns for 9 seconds after the CVR stopped. If these were from transponder 2, on the secondary radio bus, might this indicate the possibility that the crew had radio power for up to 15 seconds after the FDR ceased to operate?
I have seen no mention of comparing CVR sounds to those on the CVR for JAL. I assume that flight was airborne after the aft bulkhead failure for a sufficiently long time that the tape covering event onset was recorded over.
Assuming the FDR data trace is accurate (as well as my eyesight), the first parameter for which data is lost is engine pressure ratio for the #1 engine at 07:27:55. Most other parameters are lost around 07:27:57, with pitch being the last parameter with data recorded, stopping at 07:27:58.
The CVR stops at 07:28:03. Thus, there appears to be an interval of 7 to 8 seconds between initial loss of an FDR parameter and loss of CVR data. This would seem to be adequate time for some indication of a significant decompression to have been recorded on the CVR.
As I understand it, the data cables to the CVR and FDR run along the upper left of the cabin, and the power supply for these runs along the upper right. In a progressive failure, one might still briefly have power to the CVR and FDR and no data, or vice versa.
According to AWST, the Chinese radar recorded beacon returns for 9 seconds after the CVR stopped. If these were from transponder 2, on the secondary radio bus, might this indicate the possibility that the crew had radio power for up to 15 seconds after the FDR ceased to operate?
I have seen no mention of comparing CVR sounds to those on the CVR for JAL. I assume that flight was airborne after the aft bulkhead failure for a sufficiently long time that the tape covering event onset was recorded over.
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Here are 4 facts, and 4 questions arising from them:
Facts:
(1) There is a notation on the FDR report of a [sound similar to altitude alert] about 20 seconds before the FDR stops.
(2) This sound occurs right in the middle of the drop in the engine pressur ratio [EPR] of the #4 engine, which itself takes about 6 seconds.
(3) During and following this drop on #4, #1 and #3 show slowly rising EPRs over the about 18 seconds.
(4) The Chinese radar recorded returns for about 9 secs. after the last transponder signal recorded by the CAA.
Questions:
(a) What conditions could give rise to an [altitude alert] at 34,000 ft.?
(b) Is there any way that a small drop in an ERP could give rise to an [altitude alert], or an audible alert similar to an [altitude alert]?
(c) Are these EPR changes (#4 down, followed by #1 and #3 slowly increasing) a normal operation? e.g. for trimming purposes. Would this be an auto pilot action?
(d) The CAA recorded no transponder signals for a period of 30+ seconds about 4 mins. before the recorders on the a/c stopped. I am curious to know whether the Chinese radar recorded any transponder signals during this gap.
Facts:
(1) There is a notation on the FDR report of a [sound similar to altitude alert] about 20 seconds before the FDR stops.
(2) This sound occurs right in the middle of the drop in the engine pressur ratio [EPR] of the #4 engine, which itself takes about 6 seconds.
(3) During and following this drop on #4, #1 and #3 show slowly rising EPRs over the about 18 seconds.
(4) The Chinese radar recorded returns for about 9 secs. after the last transponder signal recorded by the CAA.
Questions:
(a) What conditions could give rise to an [altitude alert] at 34,000 ft.?
(b) Is there any way that a small drop in an ERP could give rise to an [altitude alert], or an audible alert similar to an [altitude alert]?
(c) Are these EPR changes (#4 down, followed by #1 and #3 slowly increasing) a normal operation? e.g. for trimming purposes. Would this be an auto pilot action?
(d) The CAA recorded no transponder signals for a period of 30+ seconds about 4 mins. before the recorders on the a/c stopped. I am curious to know whether the Chinese radar recorded any transponder signals during this gap.
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SaturnV ===> I share your bewilderment.
Just to live up to my name, it looks to me that the interval between the loss of the FDR and the CVR is nearer to 5 sec. than 7 to 8 secs.:
The engine EPRs seem to have been recorded in the sequence 1-2-3-4, about one report/sec. The last good report I can see seems to be for #1 just before the 07:27:58 gridline. We don’t know the exact times because the numbers on the grid lines on the time axis are rounded off, leading to the grid interval numbers sometimes beng 2 secs. and sometimes 1 sec. The next EPR report should have been for #2 about one second later, but it was never recorded. An altitude report should also have been recorded before the missing #2 was due, but also wasn’t recorded. Vertical and lateral acceleration reports were recorded at 4 per sec., and the first report to be missing would have been made just before the grid line markrd 07:27:58, and very shortly after (maybe less than 1/10 sec. after) the last signal for pitch was recorded, which, as you say, was the last good parameter of any to be recorded. So the FDR stopped millisecs. before the 07:27:58 gridline.
The CVR stopped at 07:28:03 (synchronized time), so the interval between the loss of FDR and CVR is nearer 5 sec., not 7 to 8 secs.
This does not alter the validity of what you are saying. I agree with you, its bewildering. Im just being picky about the numbers.
Question:
What progressive failures could there have been outside the pressure hull which would have allowed apparently normal flight to continue for a time? e.g. in the tail structure or wings. The tail and recorders seem to have finished up 2.6 km NE of the main wreckage, maybe due to drifting in the wind but also maybe not.
Just to live up to my name, it looks to me that the interval between the loss of the FDR and the CVR is nearer to 5 sec. than 7 to 8 secs.:
The engine EPRs seem to have been recorded in the sequence 1-2-3-4, about one report/sec. The last good report I can see seems to be for #1 just before the 07:27:58 gridline. We don’t know the exact times because the numbers on the grid lines on the time axis are rounded off, leading to the grid interval numbers sometimes beng 2 secs. and sometimes 1 sec. The next EPR report should have been for #2 about one second later, but it was never recorded. An altitude report should also have been recorded before the missing #2 was due, but also wasn’t recorded. Vertical and lateral acceleration reports were recorded at 4 per sec., and the first report to be missing would have been made just before the grid line markrd 07:27:58, and very shortly after (maybe less than 1/10 sec. after) the last signal for pitch was recorded, which, as you say, was the last good parameter of any to be recorded. So the FDR stopped millisecs. before the 07:27:58 gridline.
The CVR stopped at 07:28:03 (synchronized time), so the interval between the loss of FDR and CVR is nearer 5 sec., not 7 to 8 secs.
This does not alter the validity of what you are saying. I agree with you, its bewildering. Im just being picky about the numbers.
Question:
What progressive failures could there have been outside the pressure hull which would have allowed apparently normal flight to continue for a time? e.g. in the tail structure or wings. The tail and recorders seem to have finished up 2.6 km NE of the main wreckage, maybe due to drifting in the wind but also maybe not.
Last edited by PickyPerkins; 11th Jul 2002 at 13:15.
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"I have seen no mention of comparing CVR sounds to those on the CVR for JAL.
I assume that flight was airborne after the aft bulkhead failure for a
sufficiently long time that the tape covering event onset was recorded over."
About 32 minutes from failure to crash. Nevertheless it was reported that the
bulkhead rupture was audible on the Collins CVR (which I suppose from the era
was on a 30 minute loop). Also reported audible: a cabin decompression alarm
and the oxygen mask PA announcement.
In theory, data that has been overwritten can be recovered with as little
as 15% degradation. In practice several incidents suggest that the recovery
of data that has been overwritten can be problematic - incidents such as
runway excursions on landing after which the CVR was allowed to continue
taping.
For comparison, the US Govt protocol for "shredding" classified computer
files calls for overwriting each byte four times in a specified pattern.
I assume that flight was airborne after the aft bulkhead failure for a
sufficiently long time that the tape covering event onset was recorded over."
About 32 minutes from failure to crash. Nevertheless it was reported that the
bulkhead rupture was audible on the Collins CVR (which I suppose from the era
was on a 30 minute loop). Also reported audible: a cabin decompression alarm
and the oxygen mask PA announcement.
In theory, data that has been overwritten can be recovered with as little
as 15% degradation. In practice several incidents suggest that the recovery
of data that has been overwritten can be problematic - incidents such as
runway excursions on landing after which the CVR was allowed to continue
taping.
For comparison, the US Govt protocol for "shredding" classified computer
files calls for overwriting each byte four times in a specified pattern.
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225 died
Hey, I have an idea! Let’s think real hard combining our experience, education, and knowledge to try to figure out what happened to something we care very much about and wasn’t supposed to happen. When jump ahead, as we will, of the ‘experts’ who are conducting the ‘investigation’, we can then assist them in their quest for the probable cause should they ask or listen to us as we correspond with the more open minded of them.
If we wait, as suggested, it will be years before any action and in the intervening time, more die.
If we wait, we are considering our intelligence as worthless and not worthy of contribution.
If we wait, it means we don’t care.
So, I search out any information in the world about explosive decompression/inflight breakup events in Boeing 747s.
I correspond by email and letter to authorities and media who ask or in position to fix the problem once identified.
I hope for objective investigators unmoved by political bias or personal ambition.
I trust the answer to the question of why the event happened will come sooner than later.
Let’s think real hard combining our experience, education, and knowledge to try to figure out what happened to something we care very much about and wasn’t supposed to happen.
That’s my idea.
If we wait, as suggested, it will be years before any action and in the intervening time, more die.
If we wait, we are considering our intelligence as worthless and not worthy of contribution.
If we wait, it means we don’t care.
So, I search out any information in the world about explosive decompression/inflight breakup events in Boeing 747s.
I correspond by email and letter to authorities and media who ask or in position to fix the problem once identified.
I hope for objective investigators unmoved by political bias or personal ambition.
I trust the answer to the question of why the event happened will come sooner than later.
Let’s think real hard combining our experience, education, and knowledge to try to figure out what happened to something we care very much about and wasn’t supposed to happen.
That’s my idea.
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JohnBarrySmith:
That is without doubt the best idea I have seen on Pprune in quite some time. If we look back over air crashes in the past 60 years we will find very few that are without a political agenda of some kind. We only have to look at the finger pointing with the mid-air over Europe.
It is up to us collectively to pressure authorities to find and report the truth to advance safety.
Geoffrey Thomas
That is without doubt the best idea I have seen on Pprune in quite some time. If we look back over air crashes in the past 60 years we will find very few that are without a political agenda of some kind. We only have to look at the finger pointing with the mid-air over Europe.
It is up to us collectively to pressure authorities to find and report the truth to advance safety.
Geoffrey Thomas
The Reverend
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I doubt if anyone has the experience and knowledge or the facilities of the investigators who are searching for the answers to this tragedy. A little knowledge (as demonstrated by a lot of the posters here) is a dangerous thing and of no help whatsoever to the official investigation. Especially the conspiracy theorists! So why don't we just wait until all the pieces are found to enable the assembly of the jigsaw?
Last edited by HotDog; 14th Jul 2002 at 08:02.
>I doubt if anyone has the experience and knowledge or the facilities of the investigators who are searching for the answers to this tragedy. A little knowledge (as demonstrated by a lot of the posters here) is a dangerous thing and of no help whatsoever to the official investigation. Especially the conspiracy theorists! So why don't we just wait until all the pieces are found to enable the assembly of the jigsaw
<
Not necessarily true on many counts. A little knowledge of facts also helps to quiet conspiracies. If the facts versus the BS are not sorted out here, do we expect the general public to sort them out afterwards.
On the other hand I do agree that there is way too much speculation and agenda seeking throughout PPrune regarding investigations with little facts.
<
Not necessarily true on many counts. A little knowledge of facts also helps to quiet conspiracies. If the facts versus the BS are not sorted out here, do we expect the general public to sort them out afterwards.
On the other hand I do agree that there is way too much speculation and agenda seeking throughout PPrune regarding investigations with little facts.
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More knowledge
Speculation is not a dirty word. There is a time for it and that time is now. There is a mystery about China Airlines Flight 611 and we are all on level ground with any ideas. As far as ‘experts’ go, good, let them do what they have to do and let us ‘nonexperts’ do what we have to do.
I offer as an example of ‘nonexperts’ the Campbells of New Zealand whose son died in United Airlines Flight 811 in February 1989. Only through their efforts was the actual cause (cargo door) of the hull rupture of an early model Boeing 747 in flight that had a sudden sound followed by a power cut to the recorders (sound familiar) retrieved from the bottom of the ocean and, sure enough, the experts from NTSB, Boeing, United, etc, were wrong, wrong, wrong. The experts at NTSB had to write an entirely new AAR, 92/01, to supercede the old wrong one.
They were motivated. I am motivated. Those of us that contribute to this forum with ideas, facts, rebuttals, speculation, and even sarcasm, are motivated. We care. Indifference is the enemy. Let those who wish to wait a few years, read the press reports, hear the rumors, and then think they know what happened, let them do what they want to do.
I object to those indifferent persons suggesting to us who care that we become indifferent also as in ‘Hey!... here's a novel idea. How about saving all this keyboard stroking until the investigation is over” and ‘So why don't we just wait until all the pieces are found to enable the assembly of the jigsaw?’ and ‘On the other hand I do agree that there is way too much speculation and agenda seeking throughout PPrune regarding investigations with little facts.’
Note that the goal of the authors above is that we ‘speculators’ we who put up web sites with data points and possible interpretations, we who beg for information from those on the scene like Firehorse for some hard data, we who research past accident reports for clues, we should shut up. We should wait. We should stop talking, typing, and in effect, stop thinking.
Now, I’ve been thinking of motives of why those of us who contribute with ideas to solve the mystery of China Airlines Flight 611 do what we do.
My motive is I am a survivor of a sudden fatal jet airplane crash whose life was saved by my pilot who died. I am repaying a debt to him.
Would I be as interested in a train crash? No. A ship sinking? No. How about a robot cargo early model Boeing 747 with no one on board that takes off and has an inflight breakup at 34000 feet about a half hour after takeoff which leaves a sudden sound on the CVR and quick power cut to the recorders? Yes.
So it is the accident to the airplane itself that interests me most. Why did the plane come apart in the air? There are only a few finite realistic possibilities. All can be ruled in or out by examination of evidence.
Dear Firehorse, what is the examination of the three most likely areas of a hull rupture for China Airlines Flight 611, the forward and aft cargo door midspan latches and the aft pressure bulkhead?
Please don't let the door slam shut on the details of the civilian air crash in peacetime with no military or secret connections.
A little knowledge is very important because it leads to a lot of knowledge.
I offer as an example of ‘nonexperts’ the Campbells of New Zealand whose son died in United Airlines Flight 811 in February 1989. Only through their efforts was the actual cause (cargo door) of the hull rupture of an early model Boeing 747 in flight that had a sudden sound followed by a power cut to the recorders (sound familiar) retrieved from the bottom of the ocean and, sure enough, the experts from NTSB, Boeing, United, etc, were wrong, wrong, wrong. The experts at NTSB had to write an entirely new AAR, 92/01, to supercede the old wrong one.
They were motivated. I am motivated. Those of us that contribute to this forum with ideas, facts, rebuttals, speculation, and even sarcasm, are motivated. We care. Indifference is the enemy. Let those who wish to wait a few years, read the press reports, hear the rumors, and then think they know what happened, let them do what they want to do.
I object to those indifferent persons suggesting to us who care that we become indifferent also as in ‘Hey!... here's a novel idea. How about saving all this keyboard stroking until the investigation is over” and ‘So why don't we just wait until all the pieces are found to enable the assembly of the jigsaw?’ and ‘On the other hand I do agree that there is way too much speculation and agenda seeking throughout PPrune regarding investigations with little facts.’
Note that the goal of the authors above is that we ‘speculators’ we who put up web sites with data points and possible interpretations, we who beg for information from those on the scene like Firehorse for some hard data, we who research past accident reports for clues, we should shut up. We should wait. We should stop talking, typing, and in effect, stop thinking.
Now, I’ve been thinking of motives of why those of us who contribute with ideas to solve the mystery of China Airlines Flight 611 do what we do.
My motive is I am a survivor of a sudden fatal jet airplane crash whose life was saved by my pilot who died. I am repaying a debt to him.
Would I be as interested in a train crash? No. A ship sinking? No. How about a robot cargo early model Boeing 747 with no one on board that takes off and has an inflight breakup at 34000 feet about a half hour after takeoff which leaves a sudden sound on the CVR and quick power cut to the recorders? Yes.
So it is the accident to the airplane itself that interests me most. Why did the plane come apart in the air? There are only a few finite realistic possibilities. All can be ruled in or out by examination of evidence.
Dear Firehorse, what is the examination of the three most likely areas of a hull rupture for China Airlines Flight 611, the forward and aft cargo door midspan latches and the aft pressure bulkhead?
Please don't let the door slam shut on the details of the civilian air crash in peacetime with no military or secret connections.
A little knowledge is very important because it leads to a lot of knowledge.
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1) One has a growing sense that Firehorse may have had his hose plugged by those who do not like to have info leaking out through an unofficial pipe.
2) Well put, JohnBarrySmith! Right on.
.
2) Well put, JohnBarrySmith! Right on.
.
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Re: More knowledge
Vice Transport Minister Chang Chia-chu .......
....... A C-130 transport aircraft involved in the rescue mission also spotted a door from the ill-fated aircraft, Chang said.
Was this an isolated door?
http://au.news.yahoo.com/020526/19/8ro5.html
....... A C-130 transport aircraft involved in the rescue mission also spotted a door from the ill-fated aircraft, Chang said.
Was this an isolated door?
http://au.news.yahoo.com/020526/19/8ro5.html
Not hearing much about this one lately. I can certainly understand that Firehorse might not be able to continue posting here (alas !) but what about media coverage ? What's going on with the recovery effort ??
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Dear PickyPerkins, I am unable to read the private message as directed below. Please email me at [email protected]
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