AF 447 Search to resume (part2)
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SaturnV, don't forget that clothing tends to billow in currents and as the body moves. Jewelry just hangs there as a relatively heavy lump. Rings have a definite "detent position" on the finger, while clothing is designed for either sex or easy ingress/egress meaning its loose around the body. (I'd almost expect a tight girdle would stay on while even a bra would come off a totally limp body that is starting to decay.) Necklaces might stay on because there is the big head to get around with its ears sticking out to snag the necklace. And so forth.
Sorry Kilomikedelta, the later part of my statement was taken from the Express, i wasn't contradicting myself!
I quote.....
The Express Quotes (UK Newspaper)
Sorry for not being a little more precise with my quote!
I quote.....
The Express Quotes (UK Newspaper)
Sorry for not being a little more precise with my quote!
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Chris Scott, I just caught myself about to say the heading would have been about NNE with engine 1 being port engine coming off just a few ms after engine two. But, indications seemed to be left wing low. So it would some off earliest. That would put the orientation more like ???? I'm not REAL sure one can say much of anything about orientation. One can say that the engines came off within a couple dozen milliseconds of each other, I think. Lemme check here. Call it 113 MPH. That's coincidentally (actually with malice aforethought) 10000'/m or about 167'/s or 6ms/foot. Referencing the thread above the engines are normally about 18 meters too far apart, or about 3/8s of a second at 113 MPH.
Hm, at that rate I'd not think they would come off the plane far enough apart in time to "reverse" the positions of the engines. Presuming left wing down let's see what we get. It appears to be nonsense or an engine that stayed on the better part of a second.
So even taking the presumption that the heavy engines went straight down once broken loose doesn't tell us anything other than maybe it was really right wing low? Then it could have been headed NNE or SSW. I think the MLG will suffer the same problem.
edit: Oops - I didn't visualize very well. It COULD have been heading SE or NW to give roughly that orientation. I still sit by by confusion below.
I'm inclined to say the debris field really is jumbled randomness.
Hm, at that rate I'd not think they would come off the plane far enough apart in time to "reverse" the positions of the engines. Presuming left wing down let's see what we get. It appears to be nonsense or an engine that stayed on the better part of a second.
So even taking the presumption that the heavy engines went straight down once broken loose doesn't tell us anything other than maybe it was really right wing low? Then it could have been headed NNE or SSW. I think the MLG will suffer the same problem.
edit: Oops - I didn't visualize very well. It COULD have been heading SE or NW to give roughly that orientation. I still sit by by confusion below.
I'm inclined to say the debris field really is jumbled randomness.
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kilomikedelta, the crews are professional dive experts. But the usual things they see dead or alive are critters rather than people. I'm not sure there are very many people who've ever brought somebody up or even seen somebody during a deep dive in the ocean. I'd estimate the number as close enough to zero not to matter.
I don't remember if any of the other deep recoveries involved finding bodies. But they might have. Until I hear I'm willing to figure "no".
It's unusual that remoras and other marine critters have not found these bodies. That region of the Atlantic must be really barren. Whales vanish in other deep places in side of 2 years except for skeletons. They take a little longer to vanish.
I don't remember if any of the other deep recoveries involved finding bodies. But they might have. Until I hear I'm willing to figure "no".
It's unusual that remoras and other marine critters have not found these bodies. That region of the Atlantic must be really barren. Whales vanish in other deep places in side of 2 years except for skeletons. They take a little longer to vanish.
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Please be aware that many family members of those sadly lost are viewing this forum for information. I don't think that some of the recent posts are germane to the people flying, designing, or maintaining air transport aircraft that want to make a difference in the future by reading PPRUNE. Just suggesting a little compassion here for the family members.....
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mm43, thank you. I had overlooked that post of yours. But given that position, how to characterize the June 1 search by both Brazil and France and the negative results therefrom: incompetent, or simply inexplicable?
Both countries overflew that position on June 3 as well. Maybe by then, the currents had done their work. But the June 1 search also involved a surface ship, Douce France, searching the area of the LKP, though the exact area it searched has not been publicly revealed, one would think it concentrated on the area north of the LKP in the direction of Tasil.
____________
JD-EE, there are also the earrings. Given the soft tissue of ear lobes, I would be surprised if earrings were still there after a clothes-removing impact and submersion for five plus days.
____________
As for recovery of the bodies, I believed they recovered all the bodies that could be found from TW800.
Both countries overflew that position on June 3 as well. Maybe by then, the currents had done their work. But the June 1 search also involved a surface ship, Douce France, searching the area of the LKP, though the exact area it searched has not been publicly revealed, one would think it concentrated on the area north of the LKP in the direction of Tasil.
____________
JD-EE, there are also the earrings. Given the soft tissue of ear lobes, I would be surprised if earrings were still there after a clothes-removing impact and submersion for five plus days.
____________
As for recovery of the bodies, I believed they recovered all the bodies that could be found from TW800.
In terms of jewellery is there anything anomolous v clothing? I recall the photo's from the Canary Islands CF and some survivors had lost shirts. There was a long discussion here a year or more about this when drift etc was being obssessed about. In terms of a structure destroying event, the forces weren't that big, as witnessed time and time again by the recovered structures/jump seats not sheared out of bulkheads etc.
Owing to the uncertain seastate at impact perhaps not much point wondering about the different damage states of the wings but the distribution of wreckage still leaves my inadequate brain wondering why it isn't some indication of heading (yaw and velocity vector at impact), ie generally westerly.
Any clues as to what the northerly outlier is ?
In terms of the humanity of it, I was nearly wiped out by a car at the unseemly early age of 7. Mentally, though concious, knew nothing about it, and this was for a non-bone breaking trauma so I think there's no need to worry on that score.
Owing to the uncertain seastate at impact perhaps not much point wondering about the different damage states of the wings but the distribution of wreckage still leaves my inadequate brain wondering why it isn't some indication of heading (yaw and velocity vector at impact), ie generally westerly.
Any clues as to what the northerly outlier is ?
In terms of the humanity of it, I was nearly wiped out by a car at the unseemly early age of 7. Mentally, though concious, knew nothing about it, and this was for a non-bone breaking trauma so I think there's no need to worry on that score.
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Originally Posted by CONF iture
The text in the FCOM is a bit ambiguous but says that it is now also possible to leave the AoA protection if the sidestick is at neutral or pushed forward, for at least 0.5 seconds, when alpha is below alpha prot.
From the revised text you provided I understand that, with the sidestick at neutral, there must be some external effect (such as a downward gust?) that reduces AoA below alpha-prot while "the AoA protection law seeks to hold the angle of attack constant at alpha prot".
Last edited by Jetdriver; 10th May 2011 at 03:37.
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JD-EE
Mornin'. Not far back I think I made some points that may bear review. I think assuredly the linear arrangement of the debris has no relationship to the direction of this a/c's nose at water impact. A visual would be a look at the Schiphol accident.
Vertical velocity constrained the distribution of wreckage at impact. There was no time for pieces to 'skip' fly, or otherwise translate far away. The engines sank right away, at likely the highest velocity down of almost all the other stuff.
Depending on configuration, mass, and density, if there was no current, the system would be distributed with the engines in the center (The beginning), and increasing radii away would include a roughly even (and ~concentric) distribution of debris. There was a current which accounted for what we see as "spread", and it is tempting to assume that the orientation of the wreckage faithfully reports the "heading" of the flight at cntact with thje Sea. This is one of the fallacies of BEA's use of the words "En Ligne de Vol". This a/c was not flying, It was falling, and had not a heading, it had a trajectory, as any ballistic agglomeration of falling masses has.
We think that the direction of horizontal movement was WSW from the wreckage on the Sea floor ?? That is simplistic, since we know the distribution was current affected, and the current was responsible for the aspect of the Debris Field. The surface collection was current affected as well, also wind blown. So distribution was not influenced by nose pointing.
Any horizontal path of this a/c was immediately stopped by the dramatic "turn" this port engine low a/c experienced the second it hit. Google Groundloop, or watch the video of Sully's abrupt stop on the water's surface, or the hijacked 767, or BA038's rapid right, etc.
takata may be correct, but if so, the reciprocal would be as likely also, Again, the engines "begin" the trail, and lighter stuff is deposited "beyond" by the current, as it is the current that distributes the wreckage, not some "memory" of a (nonexistent) distribution at the surface, 2.3 miles above it.
This is my take, and of course it may be incorrect, perhaps embarrassingly so.
most respect,
bear
post #853 I tried to pattern it after your skill in describing (modelling)
Lazerdog Point well made, and noted.
Mornin'. Not far back I think I made some points that may bear review. I think assuredly the linear arrangement of the debris has no relationship to the direction of this a/c's nose at water impact. A visual would be a look at the Schiphol accident.
Vertical velocity constrained the distribution of wreckage at impact. There was no time for pieces to 'skip' fly, or otherwise translate far away. The engines sank right away, at likely the highest velocity down of almost all the other stuff.
Depending on configuration, mass, and density, if there was no current, the system would be distributed with the engines in the center (The beginning), and increasing radii away would include a roughly even (and ~concentric) distribution of debris. There was a current which accounted for what we see as "spread", and it is tempting to assume that the orientation of the wreckage faithfully reports the "heading" of the flight at cntact with thje Sea. This is one of the fallacies of BEA's use of the words "En Ligne de Vol". This a/c was not flying, It was falling, and had not a heading, it had a trajectory, as any ballistic agglomeration of falling masses has.
We think that the direction of horizontal movement was WSW from the wreckage on the Sea floor ?? That is simplistic, since we know the distribution was current affected, and the current was responsible for the aspect of the Debris Field. The surface collection was current affected as well, also wind blown. So distribution was not influenced by nose pointing.
Any horizontal path of this a/c was immediately stopped by the dramatic "turn" this port engine low a/c experienced the second it hit. Google Groundloop, or watch the video of Sully's abrupt stop on the water's surface, or the hijacked 767, or BA038's rapid right, etc.
takata may be correct, but if so, the reciprocal would be as likely also, Again, the engines "begin" the trail, and lighter stuff is deposited "beyond" by the current, as it is the current that distributes the wreckage, not some "memory" of a (nonexistent) distribution at the surface, 2.3 miles above it.
This is my take, and of course it may be incorrect, perhaps embarrassingly so.
most respect,
bear
post #853 I tried to pattern it after your skill in describing (modelling)
Lazerdog Point well made, and noted.
Last edited by bearfoil; 8th May 2011 at 15:36.
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Originally Posted by HN39
From the revised text you provided I understand that, with the sidestick at neutral, there must be some external effect (such as a downward gust?) that reduces AoA below alpha-prot while "the AoA protection law seeks to hold the angle of attack constant at alpha prot".
With that modification, maybe the 340 would not have climbed that way ... Appendix B would tell ...
Another point of interest :
At MMO the 340 received a TCAS DESCENT when the high speed protection would have sent that 340 in a ... CLIMB !?
Slower than a Citroën 2CV?
Quote from mm43:
"ROP = 023°T x 4.34NM(5 miles/8km) from LKP
Those with a calculator can come up with their own position, but the one given above will lead you to the main engines."
One assumes that both engines would have detached in the first second after sea-level impact, and then descended practically vertically the 3900m to their present position on an apparently horizontal ocean floor. To all intents and purposes, I think we can treat the sea-level impact position as approximating the engines' PPOS.
It seems implausible that a jet airliner, particularly one starting from cruise altitude, could average little more than a statute-mile-a-minute of GS ("ground" speed), even if it was in a deep-stall condition throughout the period. This would be somewhat slower than a Citroën "Deux-Chevaux".
It's unclear to this writer how the flight control system and PF could have allowed the AoA to progress above the conventional stall, even after the disconnection of the AP and downgrade to Pitch-Alternate Law at around LKP. Also, Alpha-Floor would have selected TOGA thrust before the stall, adding further energy. One has to assume that the aerodynamics of this conventional aeroplane, even at cruise CG, would also provide protection from deep stall. Others may like to calculate the TAS at Vs-min for various altitudes.
Allowing for the priority given to position reports in the ACARS-transmission hierarchy, the latest possible time at LKP was roughly 02:10:20z, and the earliest possible sea-level time was about 02:14:30z. At the end of this period of at least 4 mins10 secs, the aircraft seems to have impacted the sea only about 5 statute-miles, (26400 ft) away in azimuth. Assuming direct line of flight in azimuth, average GS would be 72 mph (62.5 kts). Average wind component during the descent is unlikely to have contributed: there is no suggestion of significant headwind.
My tentative conclusion is that direct routing in azimuth from LKP to sea-level impact does not provide sufficient mileage for the minimum flight time of 4 mins 10 secs. A series of tight S-turns might be possible, or a spin; but some kind of R/H or L/H teardrop, commencing after 02:11z, seems more likely, as I've proposed before. The teardrop would be unlikely, of course, to have been a tidy one.
"ROP = 023°T x 4.34NM(5 miles/8km) from LKP
Those with a calculator can come up with their own position, but the one given above will lead you to the main engines."
One assumes that both engines would have detached in the first second after sea-level impact, and then descended practically vertically the 3900m to their present position on an apparently horizontal ocean floor. To all intents and purposes, I think we can treat the sea-level impact position as approximating the engines' PPOS.
It seems implausible that a jet airliner, particularly one starting from cruise altitude, could average little more than a statute-mile-a-minute of GS ("ground" speed), even if it was in a deep-stall condition throughout the period. This would be somewhat slower than a Citroën "Deux-Chevaux".
It's unclear to this writer how the flight control system and PF could have allowed the AoA to progress above the conventional stall, even after the disconnection of the AP and downgrade to Pitch-Alternate Law at around LKP. Also, Alpha-Floor would have selected TOGA thrust before the stall, adding further energy. One has to assume that the aerodynamics of this conventional aeroplane, even at cruise CG, would also provide protection from deep stall. Others may like to calculate the TAS at Vs-min for various altitudes.
Allowing for the priority given to position reports in the ACARS-transmission hierarchy, the latest possible time at LKP was roughly 02:10:20z, and the earliest possible sea-level time was about 02:14:30z. At the end of this period of at least 4 mins10 secs, the aircraft seems to have impacted the sea only about 5 statute-miles, (26400 ft) away in azimuth. Assuming direct line of flight in azimuth, average GS would be 72 mph (62.5 kts). Average wind component during the descent is unlikely to have contributed: there is no suggestion of significant headwind.
My tentative conclusion is that direct routing in azimuth from LKP to sea-level impact does not provide sufficient mileage for the minimum flight time of 4 mins 10 secs. A series of tight S-turns might be possible, or a spin; but some kind of R/H or L/H teardrop, commencing after 02:11z, seems more likely, as I've proposed before. The teardrop would be unlikely, of course, to have been a tidy one.
Last edited by Jetdriver; 10th May 2011 at 02:39.
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Chris
Why are you thinking teardrop?? If the decision had been made to turn around, why not a maximum rate turn to port off the airway at some point past LKP ?? If a sudden entry into a turn, could this have caused potential recovery to be further remote??
If sudden onset of very serious problems, a teardrop or wide turn would perhaps not have conformed to the urgency of the decision ??
BTW, what do you think of turbulence as causing the a/p drop, and turbulence of sufficient force to blank, or disturb the pitots ability to read ? I am not convinced ICE is the only way to screw up the pitots feed stream.
Also, re: the WindShear ACARS, the system would have alerted rapid deviations in a/s, consistent with changing headings of airstream. These would have been deviating, showing rapid increase/decrease in a/s, and if not nose on, tail on, could this warning have been an indication of turbulence that may have caused discrepant readings in #1 and #2,3, and even #2-#3??
Why are you thinking teardrop?? If the decision had been made to turn around, why not a maximum rate turn to port off the airway at some point past LKP ?? If a sudden entry into a turn, could this have caused potential recovery to be further remote??
If sudden onset of very serious problems, a teardrop or wide turn would perhaps not have conformed to the urgency of the decision ??
BTW, what do you think of turbulence as causing the a/p drop, and turbulence of sufficient force to blank, or disturb the pitots ability to read ? I am not convinced ICE is the only way to screw up the pitots feed stream.
Also, re: the WindShear ACARS, the system would have alerted rapid deviations in a/s, consistent with changing headings of airstream. These would have been deviating, showing rapid increase/decrease in a/s, and if not nose on, tail on, could this warning have been an indication of turbulence that may have caused discrepant readings in #1 and #2,3, and even #2-#3??
Last edited by bearfoil; 8th May 2011 at 17:03.
So it came down at a steeper than 45 degree angle in about 4 minutes. Anyone familiar with what type of spin that could have been?
Since it did not disintegrate to small pieces at impact I assume that the speed at impact had to be relative benign i.e. sub 200kn.
Since it did not disintegrate to small pieces at impact I assume that the speed at impact had to be relative benign i.e. sub 200kn.
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Hi Bearfoil,
The only fallacy I'm reading, in many posts from you, is your basic understanding of what the BEA described in this first report.
Sorry to say it, but you can check by yourself the explanation I gave at this time of this "en ligne de vol" stuff.
This is a (short) old French technical aeronautical expression, no matter if you like it or not, that is exactly describing an aircraft attitude (assiette) and is meaningless concerning the "flight vectors" involved (this aircraft could be "flying" or "falling" while being "en ligne de vol" as both is right.
And, please, do not think they changed anything about their impact attitude description in the following report as they just fully worded what it means in plain text, which take two sentences instead of four words.
You may surely be critical to the BEA for something worth of it, but here, let me tell you that you are plain wrong about their wording intentions. I looked myself at the description of the impact and came back to post here that the aicraft did not "dive into the sea" but impacted possibly stalled, wings level, with a positive pitch = "en ligne de vol".
Originally Posted by Bearfoil
This is one of the fallacies of BEA's use of the words "En Ligne de Vol". This a/c was not flying, It was falling, and had not a heading, it had a trajectory, as any ballistic agglomeration of falling masses has
Sorry to say it, but you can check by yourself the explanation I gave at this time of this "en ligne de vol" stuff.
This is a (short) old French technical aeronautical expression, no matter if you like it or not, that is exactly describing an aircraft attitude (assiette) and is meaningless concerning the "flight vectors" involved (this aircraft could be "flying" or "falling" while being "en ligne de vol" as both is right.
And, please, do not think they changed anything about their impact attitude description in the following report as they just fully worded what it means in plain text, which take two sentences instead of four words.
You may surely be critical to the BEA for something worth of it, but here, let me tell you that you are plain wrong about their wording intentions. I looked myself at the description of the impact and came back to post here that the aicraft did not "dive into the sea" but impacted possibly stalled, wings level, with a positive pitch = "en ligne de vol".
Thread Starter
Salute!
The wreckage data ( distribution) we already have has a wealth of data that will be combined with the recorded parameters, IMHO. So we should get a very good replay of impact.
The big question is how in the hell the plane got there, ya think?
As far as the horizontal distance versus vertical distance goes, it is not betond my personal experience. As a light plane pilot previously recalled, if the plane is in a fully-developed stall, it can descend at a great rate without much forward velocity. In my own experience, one jet I flew had exceptional directional control in a full stall ( rudder versus aileron for maintaining a heading and picking up the low wing). Just release back pressure and it came right out. I could descend at 10,000 feet per minute or more ( the vertical velocity meter was pegged) with an indicated speed of about 60 knots. So I could go one mile and lose 10,000 feet or so.
The wreckage data ( distribution) we already have has a wealth of data that will be combined with the recorded parameters, IMHO. So we should get a very good replay of impact.
The big question is how in the hell the plane got there, ya think?
As far as the horizontal distance versus vertical distance goes, it is not betond my personal experience. As a light plane pilot previously recalled, if the plane is in a fully-developed stall, it can descend at a great rate without much forward velocity. In my own experience, one jet I flew had exceptional directional control in a full stall ( rudder versus aileron for maintaining a heading and picking up the low wing). Just release back pressure and it came right out. I could descend at 10,000 feet per minute or more ( the vertical velocity meter was pegged) with an indicated speed of about 60 knots. So I could go one mile and lose 10,000 feet or so.
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Debris pattern in seabed
Gums,
Since the first released image of Sonar Scan we could see a distinctive pattern.
IMHO this could not just be explained by sea currents.
Waiting anxiously for new information and "imagining models" to explain evidences.
The wreckage data ( distribution) we already have has a wealth of data
IMHO this could not just be explained by sea currents.
Waiting anxiously for new information and "imagining models" to explain evidences.
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Lazerdog
Please be aware that many family members of those sadly lost are viewing this forum for information.
I understand what you are implying, but I just wonder where you get your information about that statement.
One golden rule,when someone loses a love one by a tragic accident, or a criminal act, is not to watch TV, read newspapers, and now, be careful what you access on the internet. A lot of the information posted on pprune giving progress in the investigation of AF447 was originally from the media.
Please be aware that many family members of those sadly lost are viewing this forum for information.
I understand what you are implying, but I just wonder where you get your information about that statement.
One golden rule,when someone loses a love one by a tragic accident, or a criminal act, is not to watch TV, read newspapers, and now, be careful what you access on the internet. A lot of the information posted on pprune giving progress in the investigation of AF447 was originally from the media.
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I'll have to agree with Gums here. At LKP, AF447 was on its way, maybe not strongly down yet, but with greatly dissipated airspeed, probably in a relatively stable configuration, perhaps with one later gyration causing temporary loss of communications, and continuing on down until impact shortly after the last ACARS with vertical speed higher than horizontal speed.
The wing was doing what wings do at high AOA, dissipating energy.
The aircraft was intact as BEA concluded in their 2nd interim report. The path taken to the surface was not that of a "ballistic agglomeration" , but determined by aerodynamic forces and the aircraft acted as expected given that it was well outside its normal flight envelope, and it had a heading, and that heading is reflected in the wreckage distribution, however the interpretation of that distribution is made difficult since we have no hydrodynamic data on each individual piece. We can only make assumptions regarding very dense shapes and very light shapes.
The key question is how does the A330 lose its flight envelope so quickly? Others as well as myself have proposed a number of mechanisms.
The Vmo/Mmo pitch up as experienced by the A340 is but one of them. In my estimation, the dynamic loss of control models offer the best explanation since they can account for the rudder travel limiter position easily.
Pure speculation at this point, but perhaps the apparent loss of ACARS was caused by the crew trying to break a stable stall by putting in a bootfull of rudder and holding it.
That rascal Bear is trying again to introduce his theory of inflight breakup. How does a person become so focused on such an unlikely scenario?
The wing was doing what wings do at high AOA, dissipating energy.
The aircraft was intact as BEA concluded in their 2nd interim report. The path taken to the surface was not that of a "ballistic agglomeration" , but determined by aerodynamic forces and the aircraft acted as expected given that it was well outside its normal flight envelope, and it had a heading, and that heading is reflected in the wreckage distribution, however the interpretation of that distribution is made difficult since we have no hydrodynamic data on each individual piece. We can only make assumptions regarding very dense shapes and very light shapes.
The key question is how does the A330 lose its flight envelope so quickly? Others as well as myself have proposed a number of mechanisms.
The Vmo/Mmo pitch up as experienced by the A340 is but one of them. In my estimation, the dynamic loss of control models offer the best explanation since they can account for the rudder travel limiter position easily.
Pure speculation at this point, but perhaps the apparent loss of ACARS was caused by the crew trying to break a stable stall by putting in a bootfull of rudder and holding it.
That rascal Bear is trying again to introduce his theory of inflight breakup. How does a person become so focused on such an unlikely scenario?
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The Future
Hello All,
This has been a very informative thread with some extremely qualified contributors. I suspect it has been fed with some information and watched for ideas and I hope the following is noted.
I don’t post often but looking at the bigger picture, there had to be a reason why the aircraft flew into a weather system that, quite possibly, no aircraft could withstand.
The ultimate reason for the accident most likely lies within the flightdeck, the recorders may show what happened following the encounter with the weather system but in my opinion the most important point is that current and future aviators learn how to avoid the same mistakes. It will take years (if ever) for nuts and bolts systems to be built that can protect an aircraft from this sort of encounter.
The damage to the flightdeck will have been significant but following the kind of impact you mainly suspect, I know that the forensic diagnostic abilities of crash investigators are capable of discovering much.
I desperately hope that what is left of the controls within the flightdeck are retrieved, it could all be as simple as both radar displays being dimmed along with flightdeck lighting being at maximum.
For some reason they flew into a weather system that someone with conscious thought would never dream of doing.
If that is the case, the emphasis on weather avoidance needs to be changed. If it is not the case, the following is still worth considering.
Currently I fly the most modern Boeing widebodies and have flown Airbus. The Weather Radar Systems are now all automatic but not easy to interoperate. Automatic Video Enhancement is great but it removes the ability of the radar operator to interoperate a Raw Radar Picture. I know this requires skill but surely that’s what you all pay me for.
These days I am presented with the same sort of radar picture in central Europe for a cloud with only a few thousand feet vertical extent and a bit of rain as I get at 35,000ft crossing the ITCZ. The ability to display raw radar would be wonderful and pilots would absorb the skills required and information provided rapidly. In my opinion one of the worst “advances” in aviation has been the reduction in the ability of the pilot to use or improve his technical skills, specifically in this instance, in radar interpretation.
Current training about what is significant weather is poor and the attitude of Air Traffic Control in some regions of the world tends to lead pilots to only avoid significant weather if they are given permission.
In some circumstances a Green radar return is irrelevant, other times it is a “MUST AVOID”. With the modern enhanced video display, quite often all I can do is “have a nibble” at the edge, avoid if it bumps, go through if it’s OK. That is not a scientific way of working or protecting my passengers in the best way.
I desperately hope that every effort is made to recover all possible evidence. Heartbreakingly, nothing can be done for the lost souls, it must be the safety of future air travellers that should be cared for.
I hope that BEA will be following this thread, they will never admit it but, if my post nudges them to recover all that may shed any evidence on the accident, it was worth the effort. (I hope Boeing see it as well, their radar pictures are not adequate!)
This has been a very informative thread with some extremely qualified contributors. I suspect it has been fed with some information and watched for ideas and I hope the following is noted.
I don’t post often but looking at the bigger picture, there had to be a reason why the aircraft flew into a weather system that, quite possibly, no aircraft could withstand.
The ultimate reason for the accident most likely lies within the flightdeck, the recorders may show what happened following the encounter with the weather system but in my opinion the most important point is that current and future aviators learn how to avoid the same mistakes. It will take years (if ever) for nuts and bolts systems to be built that can protect an aircraft from this sort of encounter.
The damage to the flightdeck will have been significant but following the kind of impact you mainly suspect, I know that the forensic diagnostic abilities of crash investigators are capable of discovering much.
I desperately hope that what is left of the controls within the flightdeck are retrieved, it could all be as simple as both radar displays being dimmed along with flightdeck lighting being at maximum.
For some reason they flew into a weather system that someone with conscious thought would never dream of doing.
If that is the case, the emphasis on weather avoidance needs to be changed. If it is not the case, the following is still worth considering.
Currently I fly the most modern Boeing widebodies and have flown Airbus. The Weather Radar Systems are now all automatic but not easy to interoperate. Automatic Video Enhancement is great but it removes the ability of the radar operator to interoperate a Raw Radar Picture. I know this requires skill but surely that’s what you all pay me for.
These days I am presented with the same sort of radar picture in central Europe for a cloud with only a few thousand feet vertical extent and a bit of rain as I get at 35,000ft crossing the ITCZ. The ability to display raw radar would be wonderful and pilots would absorb the skills required and information provided rapidly. In my opinion one of the worst “advances” in aviation has been the reduction in the ability of the pilot to use or improve his technical skills, specifically in this instance, in radar interpretation.
Current training about what is significant weather is poor and the attitude of Air Traffic Control in some regions of the world tends to lead pilots to only avoid significant weather if they are given permission.
In some circumstances a Green radar return is irrelevant, other times it is a “MUST AVOID”. With the modern enhanced video display, quite often all I can do is “have a nibble” at the edge, avoid if it bumps, go through if it’s OK. That is not a scientific way of working or protecting my passengers in the best way.
I desperately hope that every effort is made to recover all possible evidence. Heartbreakingly, nothing can be done for the lost souls, it must be the safety of future air travellers that should be cared for.
I hope that BEA will be following this thread, they will never admit it but, if my post nudges them to recover all that may shed any evidence on the accident, it was worth the effort. (I hope Boeing see it as well, their radar pictures are not adequate!)
Last edited by woodvale; 8th May 2011 at 18:16.
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Some Points To Ponder
From the B-727 NWA 6231 NTSB Report
Pitot Information (In this case, pitot heaters were not on)
The aircraft hit the ground in a slightly nose down right wing down attitude. Except for both elevator tips, the left horizontal stabilizer, and three pieces of light structure from the left stabilizer, the entire aircraft was located within an area 180 feet long and 100 feet wide.
The aircraft and altitudes are different, but there may be some similarities between this event and AF447 relative to pitot icing and the descent, time and distance.
The sound of the stall warning stick shaker was recorded intermittently less than 10 seconds after the onset of the overspeed warning. Five seconds later, vertical acceleration reduced to 0.8g, and the altitude leveled at 24,800 feet.The recorded airspeed was 420 kn.
The stall warning began again and continued while the first officer commented, "There's that Mach buffet, 71 guess we'll have to pull it up." followed by the captain's command, "Pull it up," and the sound of the landing gear warning horn. The FDR readout shows the following:
Two seconds later (about 13 seconds after the aircraft arrived at 24,800 feet), the vertical acceleration trace again declined to 0.8g and the altitude trace began to descend at a rate of 15,000 feet per minute.The airspeed trace decreased simultaneously at a rate of 4 kn per second and the magnetic heading trace changed from 290° to 080° within 10 seconds, which indicated that the aircraft was turning rapidly to the right. As the aircraft continued to descend, the vertical acceleration trace increased to 1.5g. The aircraft's magnetic heading trace fluctuated, but moved basically to the right, the vertical acceleration trace increased immediately,with peaks to +3g. Ten seconds later, the peak values for vertical acceleration increased to +5g.The aircraft had descended from 24,800 feet in 83 seconds.
The stall warning began again and continued while the first officer commented, "There's that Mach buffet, 71 guess we'll have to pull it up." followed by the captain's command, "Pull it up," and the sound of the landing gear warning horn. The FDR readout shows the following:
Two seconds later (about 13 seconds after the aircraft arrived at 24,800 feet), the vertical acceleration trace again declined to 0.8g and the altitude trace began to descend at a rate of 15,000 feet per minute.The airspeed trace decreased simultaneously at a rate of 4 kn per second and the magnetic heading trace changed from 290° to 080° within 10 seconds, which indicated that the aircraft was turning rapidly to the right. As the aircraft continued to descend, the vertical acceleration trace increased to 1.5g. The aircraft's magnetic heading trace fluctuated, but moved basically to the right, the vertical acceleration trace increased immediately,with peaks to +3g. Ten seconds later, the peak values for vertical acceleration increased to +5g.The aircraft had descended from 24,800 feet in 83 seconds.
A pitot head of the same type that provided pitot pressure to the first officer's airspeed/Mach indicator was exposed to icing conditions in a wind tunnel. With the pitot heater inoperative, 1 to 2 inches of ice formed over the pressure inlet port. During the exposure, a thin film of water flowed into the pressure port, some-of which flowed out of the drain hole.
Blockage of the drain hole by ice seemed to depend on the length of time required for ice to form and block the total pressure inlet port. The longer it took for ice to form and block the total pressure port, the more likely it became that the drain hole would be blocked by ice. Also, the greater the angle between the longitudinal axis of the pitot head and the relative wind, the greater the likelihood that the drain hole would become blocked with ice.
Constant altitude pressure measurements showed that when the total pressure inlet port was blocked by ice and the drain hole remained open, pressure changes occurred that would cause a reduction of indicated air- speed. However, when both the total pressure port and drain hole were blocked, the total pressure remained constant, which would cause indicated airspeed to remain fixed. Also, abrupt and small pressure fluctuations occurred shortly before either the pressure port or drain hole became blocked by ice.
In an effort to reproduce the apparent inconsistencies between the airspeed and altitude values on the FDR traces, tests were conducted with an airspeed indicator and an altimeter connected to vacuum and pressure sources. By altering the vacuum to the altimeter and to the airspeed indicator, the altitude trace could be reproduced. However, following ascent above 16,000 feet, the FDR airspeed and altitude values could be simultaneously duplicated only when the total pressure to the airspeed indicator was fixed at its FDR value for an altimeter reading of about 15,675 feet and an indicated airspeed of about 302 kn.
Blockage of the drain hole by ice seemed to depend on the length of time required for ice to form and block the total pressure inlet port. The longer it took for ice to form and block the total pressure port, the more likely it became that the drain hole would be blocked by ice. Also, the greater the angle between the longitudinal axis of the pitot head and the relative wind, the greater the likelihood that the drain hole would become blocked with ice.
Constant altitude pressure measurements showed that when the total pressure inlet port was blocked by ice and the drain hole remained open, pressure changes occurred that would cause a reduction of indicated air- speed. However, when both the total pressure port and drain hole were blocked, the total pressure remained constant, which would cause indicated airspeed to remain fixed. Also, abrupt and small pressure fluctuations occurred shortly before either the pressure port or drain hole became blocked by ice.
In an effort to reproduce the apparent inconsistencies between the airspeed and altitude values on the FDR traces, tests were conducted with an airspeed indicator and an altimeter connected to vacuum and pressure sources. By altering the vacuum to the altimeter and to the airspeed indicator, the altitude trace could be reproduced. However, following ascent above 16,000 feet, the FDR airspeed and altitude values could be simultaneously duplicated only when the total pressure to the airspeed indicator was fixed at its FDR value for an altimeter reading of about 15,675 feet and an indicated airspeed of about 302 kn.
Following the accident, the Safety Board requested that the aircraft mailufacturer analyze the data from the CVR and FDR to determine (1) The consistency of these data, particularly the airspeed and altitude values, with the theoretical performance of the aircraft; (2) the significance and possible reason for a simultaneous activation of the overspeed and stall warning systems; and (3) the body attitude of the aircraft during its final ascent and descent.
The indicated airspeed of the aircraft when the stick shaker was first activated was calculated to be 165 kn as compared to the 412 kn recordedbytheFDR. The decrease in airspeed from 305kn to 165kn as the aircraft climbed from 16,000 feet to 24,000 feet (within 116 seconds) is within the aircraft's theoretical climb power performance. The aircraft's pitch attitude would have been about 30° noseup as stick shaker speed was approached. The stall warning stick shaker is activated by angle of attack instrumentation which is completely independent of, and therefore not affected by errors in, the aircraft's airspeed measuring systems. Boeing personnel interpreted the sound of the landing gear warning horn on the CVR to indicate that the thrust levers had been retarded to-idle. The second reduction in vertical acceleration to 0.8g which was coincident with atheoretical relationships of angle of attack, velocity, and drag were compared to the recorded rate of descent and load factor to determine the attitude of the aircraft after the stall. The comparison showed that the aircraft attained an angle of attack of 22°, or greater, during the descent. Transient nosedown attitudes of more than 60° would have been required to achieve the measured descent rate with an angle-of attack of 22°. The variations in load factors, which averaged about +1.5g, were attributed to variations in the aircraft's angle of bank.
The aircraft was probably exceeding 230 kn, with a nosedown attitude of about 50° as it descended below 11,000 feet.
The aircraft was probably exceeding 230 kn, with a nosedown attitude of about 50° as it descended below 11,000 feet.
The aircraft and altitudes are different, but there may be some similarities between this event and AF447 relative to pitot icing and the descent, time and distance.