AF447
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Excellent points deSitter on composite structures.
Composite structures gradually bought their way on the airframe over the decades, and it's true, they don't deflect much before failure. Would like to know when they do the fatigue testing, whether they expose the sample to temperature and humidity cycles too. The pilots can answer here, but would assume an intercontinental plane spends its whole life on one line. Swampy England, high alt cold, hot Rio and back.
For 447 however, the photographic evidence of the vertical wouldn't necessarily support THAT structure failed below design load with margin. The empennage could have been peeled from the VS for instance. In the case where the horizontal failed downward, it would have dragged the two mounting points of the VS down with it in that area of dense supporting structure, explaining the rudder corner damage, since the VS would have rotated te down. The VS would have been only momentarily attached at the front after that. Or course this would have happened very rapidly.
Either way, VS first or HS first, would indicate an overload.
Composite structures gradually bought their way on the airframe over the decades, and it's true, they don't deflect much before failure. Would like to know when they do the fatigue testing, whether they expose the sample to temperature and humidity cycles too. The pilots can answer here, but would assume an intercontinental plane spends its whole life on one line. Swampy England, high alt cold, hot Rio and back.
For 447 however, the photographic evidence of the vertical wouldn't necessarily support THAT structure failed below design load with margin. The empennage could have been peeled from the VS for instance. In the case where the horizontal failed downward, it would have dragged the two mounting points of the VS down with it in that area of dense supporting structure, explaining the rudder corner damage, since the VS would have rotated te down. The VS would have been only momentarily attached at the front after that. Or course this would have happened very rapidly.
Either way, VS first or HS first, would indicate an overload.
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The water bottles don't point to a decompression - they would have ruptured. Appear to be intact in the photo. Either there wasn't a rapid decompression, or they are sea trash.
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sounds reasonable?
June 12, 2009
'Black box' obsolete
PARIS - WHETHER or not the black boxes from Air France flight 447 are found, the crash has shown that new technology is needed to record a flight's last moments in real-time, an aviation expert argues. Former Air Canada chief executive and ex-head of the International Air Transport Association, Pierre Jeanniot helped pioneer flight data recorders 40 years ago but now says the 'black boxes' are obsolete.
'Technology has evolved,' Mr Jeanniot told AFP. 'Real-time data transmission from the cockpit by satellite is a lot less costly than it was ten years ago. It is now possible to transmit everything directly during the flight if there is a problem.'
Mr Jeanniot said an automatic system for data transmission of flight information by satellite exists and should now become the norm in the industry. It would put an end to painstaking searches like the one taking place off the coast of Brazil for AF 447's flight recorders, and allow investigators to reconstruct events in only a few clicks of a mouse.
'The plan would begin to transmit data only from the time that a malfunction occurs,' said Mr Jeanniot. 'The system can be programmed so that in the event of a serious malfunction, it transmits all data and cockpit communications non-stop. It's quite simple.'
The new advanced technology would eliminate the need for costly and often futile searches for black boxes at the bottom of the ocean or deep in the jungle, using helicopters, submarines and mobilising rescue teams.
'Through satellite transmission, everything can be collected instantly. We can know exactly where the aircraft has dropped,' Mr Jeanniot said.
More importantly, the valuable data would help grieving families. 'Can you imagine how hard it is for families to be left not knowing what happened for months, some times years?' he said.
A small Toronto-based firm StarNav is developing the state-of-the-art system to provide the real-time connection between the aircraft and the ground, said Jeanniot.
As the data would only be monitored in the event of a problem, most of the flights would not be transmitting anything at all, and there would be no risk of overloading the satellite linkups, said Mr Jeanniot. -- AFP
'Black box' obsolete
PARIS - WHETHER or not the black boxes from Air France flight 447 are found, the crash has shown that new technology is needed to record a flight's last moments in real-time, an aviation expert argues. Former Air Canada chief executive and ex-head of the International Air Transport Association, Pierre Jeanniot helped pioneer flight data recorders 40 years ago but now says the 'black boxes' are obsolete.
'Technology has evolved,' Mr Jeanniot told AFP. 'Real-time data transmission from the cockpit by satellite is a lot less costly than it was ten years ago. It is now possible to transmit everything directly during the flight if there is a problem.'
Mr Jeanniot said an automatic system for data transmission of flight information by satellite exists and should now become the norm in the industry. It would put an end to painstaking searches like the one taking place off the coast of Brazil for AF 447's flight recorders, and allow investigators to reconstruct events in only a few clicks of a mouse.
'The plan would begin to transmit data only from the time that a malfunction occurs,' said Mr Jeanniot. 'The system can be programmed so that in the event of a serious malfunction, it transmits all data and cockpit communications non-stop. It's quite simple.'
The new advanced technology would eliminate the need for costly and often futile searches for black boxes at the bottom of the ocean or deep in the jungle, using helicopters, submarines and mobilising rescue teams.
'Through satellite transmission, everything can be collected instantly. We can know exactly where the aircraft has dropped,' Mr Jeanniot said.
More importantly, the valuable data would help grieving families. 'Can you imagine how hard it is for families to be left not knowing what happened for months, some times years?' he said.
A small Toronto-based firm StarNav is developing the state-of-the-art system to provide the real-time connection between the aircraft and the ground, said Jeanniot.
As the data would only be monitored in the event of a problem, most of the flights would not be transmitting anything at all, and there would be no risk of overloading the satellite linkups, said Mr Jeanniot. -- AFP
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They look like jump seats to me, with the harness/belt stowed. How many FAs aboard, how many jumps, and were they up and about? Rather than seated due to Turbulence?
Clipped Cub couple of those bottles look like they recompressed from Cabin altitude to sea level P. If the cabin was at ~8k feet, prior to upset
and descent, if there was disint. airborne, it may have happened low enough below cruise to protect the plastic, allowing it to contain 8k air, capped, and crinkled at SL.
Clipped Cub couple of those bottles look like they recompressed from Cabin altitude to sea level P. If the cabin was at ~8k feet, prior to upset
and descent, if there was disint. airborne, it may have happened low enough below cruise to protect the plastic, allowing it to contain 8k air, capped, and crinkled at SL.
Last edited by Will Fraser; 13th Jun 2009 at 02:05.
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Originally Posted by ILS27LEFT
I say this because I am also sure they knew very well about this pitot problem and they were all well trained on how to react to loss of airspeed data at altitude and in turbulence
It is true I'm not an AF pilot, but before 447 I had never heard about these pitot malfunctions at cruise Flight Level ... or I simply can't remember.
I am quite sure I read it somewhere on an official source, I could be wrong of course but I think it is irrelevant because the fact that significant weather was in the proximity of this A/C I still see it as a clear FACT
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W.I.T.A possibly part of the crew container exterior wall???
I am somewhat suprised by the size of some of this fuselage (or contained within) debris. It has either lost a lot of its inertia and speed at altitude (following ejection from the aircraft structure), descending individually at comparatively slow speeds; OR
Spilt out of the aircraft following a comparatively slow speed water impact and break up.
The information posted on the condition of those recovered so far would not necessarily fit with the second scenario, particularly the absence of other large bits of floating debris (non-metallic cabin bits etc).
High speed (near vertical) impact of any surface (land or water) would almost certainly destroy most parts into an amalgum of very small, highly compressed ejecta (more likely to sink).
The two fold down crew seats, any views on what cabin partition bulkhead they are from (forward or aft area of the fuse)??
I am somewhat suprised by the size of some of this fuselage (or contained within) debris. It has either lost a lot of its inertia and speed at altitude (following ejection from the aircraft structure), descending individually at comparatively slow speeds; OR
Spilt out of the aircraft following a comparatively slow speed water impact and break up.
The information posted on the condition of those recovered so far would not necessarily fit with the second scenario, particularly the absence of other large bits of floating debris (non-metallic cabin bits etc).
High speed (near vertical) impact of any surface (land or water) would almost certainly destroy most parts into an amalgum of very small, highly compressed ejecta (more likely to sink).
The two fold down crew seats, any views on what cabin partition bulkhead they are from (forward or aft area of the fuse)??
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The jumpseats are most likely aft, since the radius of the perimeter of the bulkhead is small, and if that is a passage to the left of #3, that is a pair, possibly even on the aft pres bulkhead. (~unfamiliar 330) I'd like to again point out the stowed harness/belts, they were not occupied if Captain had ordered seatbelts and FAs to sit secured in the turbulence.
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Chomolungma
Now, maybe I am nuts and maybe I'm not. Bit CVR and FDR tools record continuously overwriting the old data with new data continuously. You get a couple hour record or more. The bit about wait until we're in trouble to transmit does not tell a pickled thing about how they got there. What would be needed is bandwidth sufficient to squirt up the data from the last couple of hours and then continue the data transmission until conditions return to normal or LOS (Loss Of Signal.) That initial squrt of a couple hours of data would require a TV signal sort of bandwidth to make it happen fast enough, and even then it might not all get there. Then maintaining the flow would require a narrow voice channel and a slow data channel at most. So you'd be wasting an expensive TV bandwidth channel. But it's wasted anyway because it has to be available at all times. And to make sure the most valuable data gets there first you'd have to use uncompressed data or data with a compression format that works in reverse. Send the newest data first working back to the oldest data. Ugh - the solution seems ugly to me as a communications engineer.
What MIGHT help for locating FDR and CVR is a means of automatically triggering a stream of flight data including the navigation system's estimates of position, velocity (speed and direction), and flight control settings. Cockpit voice can wait for recovery. The data would be designed to put the search as close as possible to the right place.
As many others want to do if we elected to send CVR and data with enough fidelity to get the voices well but compressed almost to death there is a good algorithm that gets it all through a 2400 bps (300 BYTES/sec) or so channel. The algorithm even tends to mute ambient noise. Somebody else mentioned the FDR stream is about 2 k BYTES a second or so. So you get a total bandwidth of about 2 to 3 k BYTES per second per plane with 10,000 planes in the air. That's an agregate data rate of 20 to 30 megabytes per second or a good two digital TV channels worth - if it's all collected and transmitted at one place.
Planes aren't all neatly packed in one place. So each is transmitting its own data. That means each one uses about 10 kHz of bandwidth, continuously, if you want reasonable error rates for a first cut round figure. That's 100 megabytes bandwidth, a piddly 17 TV signals wide or so.
Off hand that sounds terribly expensive. I'd stick to simply trying to make finding the recorders a little easier. And even that may not be worth it for a deep ocean recovery once every few years. The $100 million or even gigabuck SAR may be cheaper in the long run.
{o.o} (It would be fun to have that much bandwidth to play with. But it might also be fun to have that much money to play with.)
June 12, 2009
'Black box' obsolete
PARIS - WHETHER or not the black boxes from Air France flight 447 are found, the crash has shown that new technology is needed to record a flight's last moments in real-time, an aviation expert argues. Former Air Canada chief executive and ex-head of the International Air Transport Association, Pierre Jeanniot helped pioneer flight data recorders 40 years ago but now says the 'black boxes' are obsolete.
'Black box' obsolete
PARIS - WHETHER or not the black boxes from Air France flight 447 are found, the crash has shown that new technology is needed to record a flight's last moments in real-time, an aviation expert argues. Former Air Canada chief executive and ex-head of the International Air Transport Association, Pierre Jeanniot helped pioneer flight data recorders 40 years ago but now says the 'black boxes' are obsolete.
What MIGHT help for locating FDR and CVR is a means of automatically triggering a stream of flight data including the navigation system's estimates of position, velocity (speed and direction), and flight control settings. Cockpit voice can wait for recovery. The data would be designed to put the search as close as possible to the right place.
As many others want to do if we elected to send CVR and data with enough fidelity to get the voices well but compressed almost to death there is a good algorithm that gets it all through a 2400 bps (300 BYTES/sec) or so channel. The algorithm even tends to mute ambient noise. Somebody else mentioned the FDR stream is about 2 k BYTES a second or so. So you get a total bandwidth of about 2 to 3 k BYTES per second per plane with 10,000 planes in the air. That's an agregate data rate of 20 to 30 megabytes per second or a good two digital TV channels worth - if it's all collected and transmitted at one place.
Planes aren't all neatly packed in one place. So each is transmitting its own data. That means each one uses about 10 kHz of bandwidth, continuously, if you want reasonable error rates for a first cut round figure. That's 100 megabytes bandwidth, a piddly 17 TV signals wide or so.
Off hand that sounds terribly expensive. I'd stick to simply trying to make finding the recorders a little easier. And even that may not be worth it for a deep ocean recovery once every few years. The $100 million or even gigabuck SAR may be cheaper in the long run.
{o.o} (It would be fun to have that much bandwidth to play with. But it might also be fun to have that much money to play with.)
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I just thought I'd put a small chime in on the time stamping of the ACARS data. There are many unknowns given the particular system, but we can make some very reasonable assumptions. The incoming faults are timestamped and then the delay the manual talks about is most likely to prevent multiple logging of a single signal that may chatter erroneously from it's intended state. Since the faults are logged on a state of change this is a practical necessity of any system. That delay probably doesn't change the time stamp of the original fault. Theoretically the faults should all be logged in order then, even if different messages have different delay times. Upon being transmitted to the ACARS system, it probably doesn't retimestamp the messages. It could I suppose but it would serve no purpose.
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If those are aft jumpseats, it would be nice to know where in the Ocean they were found relative to the VS. If close together, it may suggest an aft fuselage failure in concert with loss of VS and aft bulkhead. Were there nine FAs aboard?
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it may have happened low enough below cruise to protect the plastic, allowing it to contain 8k air, capped, and crinkled at SL.
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It is unlikely any loss of cabin pressurization caused a total failure of the fuselage. If the hull breached, the loss of pressure is a given. If the pressure was lost, one is forced to assume a small opening, because if it was a major opening, that would qualify it is a disintegration. Sounds confusing, and mostly semantics, but technically it isn't. Whatever pressure issue the ACARS message indicated, it is most unlikely to be a hull 'disintegration'; that would be expected to have engendered earlier and more critical ACARS data, meaning aerodynamic loads that were unsustainable. So it seems more likely that hull fragmentation occurred first, with an obvious loss of all pressure difference (perhaps gain?) immediately. Depending on a/c altitude at failure.
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There are many unknowns about how fatigue accumulates in composite structures. We know in one case that the VS mounting lugs failed laterally, all at once, across many layers of composite material, in AA587. This must have taken the structural engineers somewhat by surprise.
Composite structures gradually bought their way on the airframe over the decades, and it's true, they don't deflect much before failure.
The first being the Air Transat case of a rudder oscillating violently and breaking off while cruising on autopilot, and the second a Fedex aircraft in which severe delaminations had been found - thankfully before it misbehaved.
To quote the Canadian report, "The NTSB investigation into this occurrence has determined that the initial delamination was the result of the infiltration of hydraulic fluid in the honeycomb material of the rudder, which appears to be linked to the vulnerability of rudders built before modification 8827, affecting about 370 Airbus A300-600/A310 and 40 Airbus A330/A340. Tests of this rudder in a depressurisation chamber resulted in significant further growth in the damage. Although a direct correlation between the Air Transat and the FedEx event has not been established at this time, the event confirms that significant delamination of these rudders can progress unnoticed, in spite of the present maintenance standards in place."
Transportation Safety Board of Canada | Transportation Safety Board of Canada - Aviation Safety Recommendation A06-05
It turned out that such tap tests as had been carried out up to that time were on the wrong parts of the rudder/fin assembly.
So the good news is that the A300/A310 problem has now been found and rectified, and should not recur; and that it was not the direct result of composite construction. The other 'news' is that (since the FDRs of the time recorded pedal movement and rudder movement, but were not able to 'say' whether the pedals moved the rudder or vice versa) AA587 may well not have been pilot error at all.
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Burst Transmissions
ok - I do know something about IT and can confirm that satellite internet connections are available with downlink speeds of 400 Mb/sec. If you could do uplink ASCII bursts to relay geostationary satellites you could transmit all your FDR and FVR data in sub second UHF bursts every few mins or so and it probably would not require that many frequencies to cover half a hemisphere's flights.
Of course it all comes down to the filthy lucre in the end as it would require at least eight satellites and a few automated ground stations. But then you could do away with your black HMV boxes.
Given the fact that some airlines are now offering inflight broadband connections, you might think that the voice and data recorders would get access to the same technology.
Of course it all comes down to the filthy lucre in the end as it would require at least eight satellites and a few automated ground stations. But then you could do away with your black HMV boxes.
Given the fact that some airlines are now offering inflight broadband connections, you might think that the voice and data recorders would get access to the same technology.
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INTEL101 - or anyone else who knows the technology -am I correct in thinking that ACARS transmissions via satellite require a directional antenna; and that, for each transmission, the antenna has to aim a signal at the satellite and receive an acknowledgement before it transmits?
If so, could that mean that for most of the four minutes the aeroplane was in something like a normal flightpath - but that it was pitching and rolling from turbulence or the flightcrew's efforts to re-establish control? So that the antenna had to line up on the satellite several times, each time waiting for the acknowledgement and then sending a burst of messages? But then losing contact and having to start over?
If so, could that mean that for most of the four minutes the aeroplane was in something like a normal flightpath - but that it was pitching and rolling from turbulence or the flightcrew's efforts to re-establish control? So that the antenna had to line up on the satellite several times, each time waiting for the acknowledgement and then sending a burst of messages? But then losing contact and having to start over?
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The "Satellite Streaming CVR/FDR" discussion is ill guided. Improving the devices existing (lighter, stronger beacons with much longer endurance for deep sea detection etc.) is all that is needed.
Regarding technology for continuous broadband satellite connections etc. it is all there already. UAV are used for a long time now.
Wherever this goes, I'm afraid it will be one more step toward fully automated commercial flying, even though at the moment it is still far away.
Regarding technology for continuous broadband satellite connections etc. it is all there already. UAV are used for a long time now.
Wherever this goes, I'm afraid it will be one more step toward fully automated commercial flying, even though at the moment it is still far away.
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RWA - The ACARs messages go via any of one 4 (soon to be 7) operation Inmarsat sateliites (plus backups). The SATCOMs is continously tracking the satellite on which the A/C has logged-on. The Inmarsat Aero air-interface should allow any ACARS messages to be transmitted within a few seonds in normal circumstances and certainly in less than a minute if the Ground Earth Station is operating normally.
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I do know something about IT and can confirm that satellite internet connections are available with downlink speeds of 400 Mb/sec.
Stuff like BGAN only does around 400kb/s. Even modern platforms such as "SPACEWAY" only get up to 30Mbps.
Believe me, it's going to be a looooong time before you see 400Mbps coming from a satellite !
Units .... units...... always verify your units !