AF447
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Maybe It is time for Airbus to reconsider the fact that when redundancies are lost, only then, Pilots will be in dire need for protections to kick in
Redundancies are here to exclude failures. Protections must be able to differentiate good from bad, thus rely on redundancies!!!!!
Don't forget: One redundancy is the pilot. If you want some higher up protection to set in when some technical redundancy fails, you would effectively take the pilot out of the eqation. This happened with the QF flight, as the failed ADIRU told the aircraft to be too high and ordered descent, the pilots realised this was wrong, switched off the AP and wanted to pull just to have the holy FBW to deny this input!
For such cases the new instructions by Airbus now instructs pilots to go by a AIC circular checklist and start to disable some computers with switches on the overhead panel. This is finally realising that only a non FBW partner in redundancies can remedy the situation. All this during a highly surprising and unexpected manoever. Not enirely realistic any pilot would admit.
Now some people are shouting for even more, new protections when the initial ones fail.
All this recalls in me Goethe's Sorcerer's Apprentice when he finally concludes:
"From the spirits that I called Sir, deliver me!"
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3 flight crew
One is resting, two are in pilot's seats. Where is the resting guy according to AF sop? Is the rest compartment just behind the flight deck or in the "cellar" in the middle of the aircraft? There are different solutions as you know. And then the possibilities to reach flight deck in an emergency are different I would say.
(60+ Captain, now on MD80 but b4 on A330/340)
(60+ Captain, now on MD80 but b4 on A330/340)
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Una hipótesis a tener en cuenta (esta sí)
Written by Pedro Guil
Thursday 04 June 2009 20:01
Written by Pedro Guil
Thursday 04 June 2009 20:01
Hello Colleagues, I have a theory regarding the malignant potential cause of the crash of Air France's Airbus, and is based on my own experience. The meteorological phenomenon happened to me in the area where the plane crashed on May 9, 2001, when we returned from Buenos Aires with a B-747-300 TF-ATH enrollment, Air Atlanta flight for Iberia at that time. Since we overflight from Rio de Janeiro, still exactly the same route as the AF447 and passing through the area around the accident while crossing the ITFZ at FL-370, with a moderate to strong turbulence, in a matter of 1 to 2 minutes of flight, we experienced a sudden rise in outside temperature from -48 º C to -19 º C. As a result of this rise in temperature, we turn out to fly with a margin of 10,000 kg, to became 15,000 kg away from standards to that level flight, and with immediate initiation of an aircraft loss, with strong vibrations. We disconnected the autopilot and went down, losing 4000ft, founding us in the "coffin corner" meaning this that the plane was giving "loss" for high and low speed, and If we have not disconnected the autopilot and went down, perhaps today we would be in the bottom of the ocean making company to Air France´s plane; the autopilot would have tried to maintain altitude incrementing the power of the engines .... and that´d been impossible, and perhaps we would have entered into an abnormal position very difficult to recover because of the night and the spatial disorientation beeing into clouds.
Lately, I've been flying until February 2009 the A-340 and the "crisis" sent me to "dry dock"; having made lots of times the same route, Rio - Madrid I have not been back to this exceptional meteorological circumstance in 40 years working as airline pilot, it only happened once. I would describe as a huge funnel with a diameter of 40 nautical miles of extremely hot air and as a result of a forming CB or something similar, ascending to great heights, affecting us and after about 5 minutes flying with the "tight ass" it began again to normalize backing the temperature back -48 º C and then being able to rise again to FL-370.
According to the Airbus approach, flying in severe turbulence or strong, you do not disconnect the autopilot, but what is not expected it this kind of phenomenon that comes to my mind ... and if they didn´t disconnect the AP for not noticing this phenomenon (if it happened) in my humble opinion they may have been into abnormal positions and the plane may have been broken, this theory supports the order of messages ACARS (which are automated messages sent by the plane via satellite without intervenction of the pilots) received.
Lately, I've been flying until February 2009 the A-340 and the "crisis" sent me to "dry dock"; having made lots of times the same route, Rio - Madrid I have not been back to this exceptional meteorological circumstance in 40 years working as airline pilot, it only happened once. I would describe as a huge funnel with a diameter of 40 nautical miles of extremely hot air and as a result of a forming CB or something similar, ascending to great heights, affecting us and after about 5 minutes flying with the "tight ass" it began again to normalize backing the temperature back -48 º C and then being able to rise again to FL-370.
According to the Airbus approach, flying in severe turbulence or strong, you do not disconnect the autopilot, but what is not expected it this kind of phenomenon that comes to my mind ... and if they didn´t disconnect the AP for not noticing this phenomenon (if it happened) in my humble opinion they may have been into abnormal positions and the plane may have been broken, this theory supports the order of messages ACARS (which are automated messages sent by the plane via satellite without intervenction of the pilots) received.
Per Ardua ad Astraeus
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Taking a deep breath, I ask if we can possibly summarise what is known or can be REASONABLY deduced out of all this dross? I do, however, feel that we can rule NOTHING out at this stage:-
1) Is it safe to assume that the apparent sequential system 'failures' were triggered by the weather conditions in the area?
2) Is it safe to assume that standby attitude would probably still be available? (difficult to determine above!)
3) Is it safe to assume that engine control would be unlikely to be compromised by the known 'failures'?
4) Is the reported 'inability' of the AB 330 probe system to cope with 'heavy' icing a fact, or just more of the rubbish here? If known, was there any qualification to the release to service (icing) and if not, why not?
5) Has anyone yet established what MEL items were extant?
I'm not sure how many pilots here have actually experienced 'severe' turbulence in an airliner. I have, once, and I was scared (and I do not scare easily). If we interpret the 'hard' turbulence report as meaning severe, I pity that crew. Throw in system 'failures' and it is a one-way street in my opinion. In my experience, we had to make an emergency descent to avoid loss of control (737 with ALL systems working), and I can assure all that it can be extremely difficult even to think rationally in that situation. I was waiting for 'something to break', and needed the Boeing 'yoke' to hang on to, and I do wonder how you cope with a tiny sidestick? Can you avoid involuntary inputs while being tossed around?
Moving on, NB away from facts:
I would expect (my supposition only) that the crew were left with no option but to make a descending turn-back. That there was apparently no call (heard) to advise other traffic (iaw oceanic procedures) I find surprising as it is a fairly high priority matter, more-so than position reports. Assuming they were operating IAW SOPs therefore I suspect they were already out of control at this point.
1) Is it safe to assume that the apparent sequential system 'failures' were triggered by the weather conditions in the area?
2) Is it safe to assume that standby attitude would probably still be available? (difficult to determine above!)
3) Is it safe to assume that engine control would be unlikely to be compromised by the known 'failures'?
4) Is the reported 'inability' of the AB 330 probe system to cope with 'heavy' icing a fact, or just more of the rubbish here? If known, was there any qualification to the release to service (icing) and if not, why not?
5) Has anyone yet established what MEL items were extant?
I'm not sure how many pilots here have actually experienced 'severe' turbulence in an airliner. I have, once, and I was scared (and I do not scare easily). If we interpret the 'hard' turbulence report as meaning severe, I pity that crew. Throw in system 'failures' and it is a one-way street in my opinion. In my experience, we had to make an emergency descent to avoid loss of control (737 with ALL systems working), and I can assure all that it can be extremely difficult even to think rationally in that situation. I was waiting for 'something to break', and needed the Boeing 'yoke' to hang on to, and I do wonder how you cope with a tiny sidestick? Can you avoid involuntary inputs while being tossed around?
Moving on, NB away from facts:
I would expect (my supposition only) that the crew were left with no option but to make a descending turn-back. That there was apparently no call (heard) to advise other traffic (iaw oceanic procedures) I find surprising as it is a fairly high priority matter, more-so than position reports. Assuming they were operating IAW SOPs therefore I suspect they were already out of control at this point.
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I will not speculating,
but from now with all the concrete fact we have, A/C being in a severe Icing condition, leading to a loss of many parameters
with the full parameters I’ve got now, it is clear for me that A/C condition was out of normal condition
I’m surely an engineer specialist, with quite a good and long experience on this A/C, but rationally, I still can.t explain this !!!!!!!!!!!!!
but from now with all the concrete fact we have, A/C being in a severe Icing condition, leading to a loss of many parameters
with the full parameters I’ve got now, it is clear for me that A/C condition was out of normal condition
I’m surely an engineer specialist, with quite a good and long experience on this A/C, but rationally, I still can.t explain this !!!!!!!!!!!!!
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I still can.t explain this !!!!!!!!!!!!!
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From the BBC website
The Air France jet which went missing over the Atlantic sent 24 error messages before it is believed to have crashed, French investigators say.
The messages came as the plane's systems broke down one by one, said Alain Bouillard, head of France's aviation accident investigation bureau.
French weather experts said there was no evidence the plane, carrying 228 people, hit an "exceptional" storm.
The Airbus A330 vanished en-route from Rio de Janeiro to Paris on Monday.
The Air France jet which went missing over the Atlantic sent 24 error messages before it is believed to have crashed, French investigators say.
The messages came as the plane's systems broke down one by one, said Alain Bouillard, head of France's aviation accident investigation bureau.
French weather experts said there was no evidence the plane, carrying 228 people, hit an "exceptional" storm.
The Airbus A330 vanished en-route from Rio de Janeiro to Paris on Monday.
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Guys,
When reading the acars reports the type (typ) message is important. Keep in mind the chicken and the egg: Faults frequently cascade into Warnings. (FLR=Fault Report) (WRN = Warning) In the code block: Faults are six digit (FR). Warnings only four usable (WN).
greenspinner wrote:
Maybe this is very significant Greenspinner. Are you thinking that the fault 3422 ISIS at 0211z is an Lack of Input Data From the Standby Probes?
This could lead credence to the theory that ALL probes and pitots iced up meaning: there was nothing left to switch to, and nothing left to fly on pitot static wise (a/s, alt, v/s). This would explain why all three Air Data computers gave up, and why the rudder limiter gave up, and why a cascade of warnings hit the crew.
I'm going to speculate, that a jet upset into thicker air that's recoverable, occurs in roughly 60 seconds. Any takers? I base this on an actual emergency decent we did in a 747 from FL430 with the gear down/boards up and decent at .86M?/320kts. We think we exceeded 10,000/min. The Capt was an Edwards Test pilot. What happens is you get into a test pilot world where a phenomenon known as "dynamic spillage" occurs. At this speed, and with engines at idle, most of the relative wind can no longer pass through the engines. It instead bounces out off the N1 fan, back around the outside of the engine cowl. It creates a pronounced shutter/buffet from the engines wagging back and forth on the pylon. It is a violent maneuver and nothing like the simulator. At the stand, I spent ten minutes trying to pick my pencils pens and flight bag contents out from behind the copilots rudder peddles.
But for any FAA guys reading this: This is a fictional story for educational purposes only.
So Theoretically,
If they iced up at 0210z..... they flew for another three minutes before the really unlucky event hit them at 0213z: the loss of full flight controls.
We know now, from our techs here at Pprune, that the last acars transmission (0214z) was a #2131 Advisory WARNING: Cabin Rate Change. This does not mean depressurization. It is a warning that at your current rate of aircraft descent, that you will "catch" the cabin too early (before you land) and this will hurt your ears dearly. The remedy on normal ops is to manually select the pressurization rate knob to a greater cabin-descent rate position. Translation: At 0214z they were already in the high dive.
Opinions? (from jet pilots, mechs..)
Now Spinner, what, precisely, do you feel is a 22-83-34 flt cntrl fault?
CC
When reading the acars reports the type (typ) message is important. Keep in mind the chicken and the egg: Faults frequently cascade into Warnings. (FLR=Fault Report) (WRN = Warning) In the code block: Faults are six digit (FR). Warnings only four usable (WN).
greenspinner wrote:
ISIS reset
ISIS on this case doesn't fail , just reporting bad input.
The fact you quote is that ISIS need a reset after a quite long operating, but now it's over, we don't have to reset ISIS CB after that time.
from my own, and as the data I've got message related to ISIS means no data from Stby probes ....
ISIS on this case doesn't fail , just reporting bad input.
The fact you quote is that ISIS need a reset after a quite long operating, but now it's over, we don't have to reset ISIS CB after that time.
from my own, and as the data I've got message related to ISIS means no data from Stby probes ....
This could lead credence to the theory that ALL probes and pitots iced up meaning: there was nothing left to switch to, and nothing left to fly on pitot static wise (a/s, alt, v/s). This would explain why all three Air Data computers gave up, and why the rudder limiter gave up, and why a cascade of warnings hit the crew.
I'm going to speculate, that a jet upset into thicker air that's recoverable, occurs in roughly 60 seconds. Any takers? I base this on an actual emergency decent we did in a 747 from FL430 with the gear down/boards up and decent at .86M?/320kts. We think we exceeded 10,000/min. The Capt was an Edwards Test pilot. What happens is you get into a test pilot world where a phenomenon known as "dynamic spillage" occurs. At this speed, and with engines at idle, most of the relative wind can no longer pass through the engines. It instead bounces out off the N1 fan, back around the outside of the engine cowl. It creates a pronounced shutter/buffet from the engines wagging back and forth on the pylon. It is a violent maneuver and nothing like the simulator. At the stand, I spent ten minutes trying to pick my pencils pens and flight bag contents out from behind the copilots rudder peddles.
But for any FAA guys reading this: This is a fictional story for educational purposes only.
So Theoretically,
If they iced up at 0210z..... they flew for another three minutes before the really unlucky event hit them at 0213z: the loss of full flight controls.
We know now, from our techs here at Pprune, that the last acars transmission (0214z) was a #2131 Advisory WARNING: Cabin Rate Change. This does not mean depressurization. It is a warning that at your current rate of aircraft descent, that you will "catch" the cabin too early (before you land) and this will hurt your ears dearly. The remedy on normal ops is to manually select the pressurization rate knob to a greater cabin-descent rate position. Translation: At 0214z they were already in the high dive.
Opinions? (from jet pilots, mechs..)
Now Spinner, what, precisely, do you feel is a 22-83-34 flt cntrl fault?
CC
Last edited by Captain-Crunch; 6th Jun 2009 at 10:57. Reason: spelling, include mechanics
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Greenspinner,
Thanks for your input, being a Boeing man I could not see that Airbus would have any other power supply for the ISIS than from the hot battery bus, so of all the ACARS transmitted messages the one relating to the ISIS grabbed my attention.
It is very easy (Boeing and Airbus) to, during the conversion ground-school, simplify the various systems under the " need to know" banner.
With regard to standby horizons (as we all used to call them) it amazed me during my 777 conversion, that technology had coaxed a laser to spin and act as a gyro (the way the Boeing SAARU was described), or as avspook describes the ISIS has an internal Fibre Optic Gyro (FOG) with no moving parts.
Concentrating on standby attitude indication (putting aside the other data that the ISIS provides to the crew), as long as there is battery power these "gyro's" should continue to proved basic standby indications of attitude.
What the Boeing course didn't cover was did the SAARU (and ISIS in the case of an Airbus) being unlike the old horizon with gimbals have any "limits" in roll and pitch, beyond which the internal checking would have suggested a fault and generated a maintenance message? If not, in the case of the ISIS, could the message have been generated by "erroneous" airspeed data being circulated within the ISIS, with the crew still having a downgraded ISIS still providing basis attitude indication to the crew?
Only Airbus can answer these questions, rather than us, as professional pilots on this forum, who have only been subjected the the "need to know" brainwashing technical courses!
What the communications from Airbus , Air France and the investigators yesterday led us to believe is that they have (perhaps), even without the flight recorders found, a common thread that could have produced so many pieces of electronic equipment having been downgraded/failed... unreliable airspeed.
Lets hope they find the recorders...
Thanks for your input, being a Boeing man I could not see that Airbus would have any other power supply for the ISIS than from the hot battery bus, so of all the ACARS transmitted messages the one relating to the ISIS grabbed my attention.
It is very easy (Boeing and Airbus) to, during the conversion ground-school, simplify the various systems under the " need to know" banner.
With regard to standby horizons (as we all used to call them) it amazed me during my 777 conversion, that technology had coaxed a laser to spin and act as a gyro (the way the Boeing SAARU was described), or as avspook describes the ISIS has an internal Fibre Optic Gyro (FOG) with no moving parts.
Concentrating on standby attitude indication (putting aside the other data that the ISIS provides to the crew), as long as there is battery power these "gyro's" should continue to proved basic standby indications of attitude.
What the Boeing course didn't cover was did the SAARU (and ISIS in the case of an Airbus) being unlike the old horizon with gimbals have any "limits" in roll and pitch, beyond which the internal checking would have suggested a fault and generated a maintenance message? If not, in the case of the ISIS, could the message have been generated by "erroneous" airspeed data being circulated within the ISIS, with the crew still having a downgraded ISIS still providing basis attitude indication to the crew?
Only Airbus can answer these questions, rather than us, as professional pilots on this forum, who have only been subjected the the "need to know" brainwashing technical courses!
What the communications from Airbus , Air France and the investigators yesterday led us to believe is that they have (perhaps), even without the flight recorders found, a common thread that could have produced so many pieces of electronic equipment having been downgraded/failed... unreliable airspeed.
Lets hope they find the recorders...
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...If we interpret the 'hard' turbulence report as meaning severe...
When people report a few bumps (2 - 5 knots of airspeed change and no vertical changes as Moderate or Sever turbulance, the inexperienced pilots hearing this, and THEN experiencing THAT turbulance are lead into a false sense of what Moderate or Severe really means.
Then, when a prog report indicates "...Mod to Sev turb associated...", etc, they don't really understand what that will mean should they decide to blunder through that weather system.
According to a NASA document I read several years ago, you are experiencing severe turbulance when your aircraft is experiencing a GREATER then 25 KIAS airspeed change and close to a 2000 foot per minute IVSI change.
Keep this in mind that next time you see weather that CAN cause Sever turbulance. And also, when you report it.
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The position that has been quoted and associated with the final ACARS has come from somewhere. Would seem that the ACARS was on SAT and the position was also transmitted at the same time.
UN873
UTC W/P Lat Long True Mag NM GS
0133 INTOL 1 21.7S 32 49.9W
027.9 045.7 182.2 540KTS
0153 EPODE 1 19.4N 31 24.7W
027.9 045.7 62.7 540KTS
0200 ORARO 2 14.8N 30 55.4W
022.3 040.1 86.4 300KTS
0214 Final 3 34.7N 30 22.5W
The 0214z report places the a/c 8.5NM left of track, and the GS noted are relative for the times and distances run, though at what point track and speed deviations were actually made is unknown.
Peak CB activity has been determined at 0200z (ORARO) though the edges of the CB cells were well beyond that position.
mm43
UN873
UTC W/P Lat Long True Mag NM GS
0133 INTOL 1 21.7S 32 49.9W
027.9 045.7 182.2 540KTS
0153 EPODE 1 19.4N 31 24.7W
027.9 045.7 62.7 540KTS
0200 ORARO 2 14.8N 30 55.4W
022.3 040.1 86.4 300KTS
0214 Final 3 34.7N 30 22.5W
The 0214z report places the a/c 8.5NM left of track, and the GS noted are relative for the times and distances run, though at what point track and speed deviations were actually made is unknown.
Peak CB activity has been determined at 0200z (ORARO) though the edges of the CB cells were well beyond that position.
mm43
Does anyone know how the final position ties in with the current SAR location?
(And yes, I do realise that "final position" is where the last report came from, not necessarily where the point of impact was. but around about that location must be a good starting point)
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ACARS Message regarding TCAS
First of all, my sincere respect for the knowledgeable discussion on here - extremely enlightening and informative, thank you very much!
After going through the posts, I have been musing about the ACARS message regarding TCAS (3443005) transmitted at 02:10. Can anything more specific than a TCAS fault be inferred from this code?
Generally, since it relies on ADIRU input for ownship pressure altitude (looped through the Mode S transponder according to the A320 AOM I have at hand, 1.34.80 P3, REV 23), I would expect TCAS to degrade, at minimum, to TA only level upon ADIRU failure.
Therefore - please correct me if I am mistaken - I think the TCAS error might be regarded as further indication for inconsistent/erroneous/unavailable air data sensor input - unless somebody can validate the claim by avherald.com that it relates to the TCAS antenna.
Regarding ADS-B, it is indeed intended, among others, for enhanced surveillance in non-radar airspace.
The implementation via 1090 MHz extended squitter (DF = 17) allows the transmission of, among others, Airborne Position Messages (~2 per second), Airborne Velocity Messages (~2/s) and Identification Messages (~1/5 s). This will give anyone interested in receiving the data the F-PLN callsign and flight state information within a range of, IIRC, ~ 200 nm.
Since the airframe was fairly new, I would expect from personal observation of more recently delivered Airbus aircraft that it was already equipped with ADS-B out. However, there was probably no-one within range to receive the data.
Chris
After going through the posts, I have been musing about the ACARS message regarding TCAS (3443005) transmitted at 02:10. Can anything more specific than a TCAS fault be inferred from this code?
Generally, since it relies on ADIRU input for ownship pressure altitude (looped through the Mode S transponder according to the A320 AOM I have at hand, 1.34.80 P3, REV 23), I would expect TCAS to degrade, at minimum, to TA only level upon ADIRU failure.
Therefore - please correct me if I am mistaken - I think the TCAS error might be regarded as further indication for inconsistent/erroneous/unavailable air data sensor input - unless somebody can validate the claim by avherald.com that it relates to the TCAS antenna.
Regarding ADS-B, it is indeed intended, among others, for enhanced surveillance in non-radar airspace.
The implementation via 1090 MHz extended squitter (DF = 17) allows the transmission of, among others, Airborne Position Messages (~2 per second), Airborne Velocity Messages (~2/s) and Identification Messages (~1/5 s). This will give anyone interested in receiving the data the F-PLN callsign and flight state information within a range of, IIRC, ~ 200 nm.
Since the airframe was fairly new, I would expect from personal observation of more recently delivered Airbus aircraft that it was already equipped with ADS-B out. However, there was probably no-one within range to receive the data.
Chris
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I´m wondering why the pilots didn´t make a distress signals for ex "may day", if you have at least 5 seconds you will, and if you have entire electrical loss you will still have the battery with vhf 1. Besides I don´t know why the 3 ELT didn´t work, they start to work with an impact or with a number of g´s force.
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Separate fact from fiction
There was much talk in the press of a manually entered ACARS entry regarding entering CB.
Is there any independant evidence of this transmission other than it being in the press?
No agenda behind the question, I'm simply separating press speculation and interpretation from the factual evidence, such that it is.
Is there any independant evidence of this transmission other than it being in the press?
No agenda behind the question, I'm simply separating press speculation and interpretation from the factual evidence, such that it is.
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Pitot tubes ?
PITOT TUBES
JUST SEEN THIS - IT COULD BE OF INTEREST TO YOU GUYS AND THIS THREAD .
Air France orders vital components replaced on jets - World news, News - Belfasttelegraph.co.uk
JUST SEEN THIS - IT COULD BE OF INTEREST TO YOU GUYS AND THIS THREAD .
Air France orders vital components replaced on jets - World news, News - Belfasttelegraph.co.uk
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Some thoughts about the scale of any recovery operation
I think it's worth putting some sort of perspective into the logical next step of the operation: that of locating the wreck and the FDR & CVR.
We don't have to go further back in time than a dark eastern Canadian night in early September 1998...
SWR111 impacted intact at 20° AND, ~110° right bank at 350kts: a ‘steep water entry’. At impact Eng 1 was producing ‘high power’, No 2 was windmilling following shutdown in flt and No 3 producing slightly more than flt idle.
Although it impacted at speed, the acft was not in freefall thus terminal velocity had not been achieved and the acft did not break up prior to hitting the water.
All souls perished instantly from the deceleration (350g) and only fragments of human remains were recovered, to be identified by dental records and/or DNA.
A seismic event was recorded by a land station. The wreck came to rest a few miles offshore at a depth of 55m. The resultant ‘relatively compact’ debris field measured 125 x 95m. The terrain was undulating, silted and at bottom around 1m visibility. The accident occurred on 2nd Sep 98, with the FDR recovery on 6th Sep and the CVR on 11th Sep. From 'only' 55m. The FDR/CVR situation was compounded by their respective ULB broadcasting on the same frequency, frustrating efforts to pinpoint their origin, and in a state of becoming detached from either recorder. Jet-A fuel was apparent on the surface for a few hours prior to evaporating.
Transpose this scenario with the aid of the few known factors thus far in the AFR447 case, and it is fairly obvious that if we, for the sake of simplicity, take the depth of the Atlantic in the general region of the point of impact as 5500m (10 times the depth of SWR111 and hundreds of miles from land), then the debris field would be of the order of 13 x 10 kilometres.
This, in mountainous terrain, with the valleys mainly filled with pooling mud.
And that’s assuming that the acft impacted in one piece.
If it had reached terminal velocity (rough calcs according to Stoke’s Law would put the plunge at around 400~500kts depending on superstructure presentation relative to the surface) and consequently broken up on its way down, just multiply the debris field projections by the number of impact points, and compare that with the scale and effort that went into the SWR11 recovery and you’ll quickly appreciate why the French are already hedging their bets and warning that the FDR & CVR may well never be found.
The apparent lack of any appropriable seismographic event may conceivably be due to a large number of fragments impacting at different velocities, at different locations and slightly different times.
This, however, runs diametrically contrary to the hitherto lack of flotsam and jetsam on the surface. More break-up prior to impact would presumably imply more lighter debris, spread over a significant area.
In summary the rule of thumb in this contributor’s humble opinion would be that the ‘needle-in-the-haystack’ operation – on paper – would command the effort of the recovery of SWR111 raised to the power of ten. At a conservative estimate.
How far do you go? How far would you need to?
Sincerely,
PB (one who lost two colleagues in the pointy end of SWR111)
We don't have to go further back in time than a dark eastern Canadian night in early September 1998...
SWR111 impacted intact at 20° AND, ~110° right bank at 350kts: a ‘steep water entry’. At impact Eng 1 was producing ‘high power’, No 2 was windmilling following shutdown in flt and No 3 producing slightly more than flt idle.
Although it impacted at speed, the acft was not in freefall thus terminal velocity had not been achieved and the acft did not break up prior to hitting the water.
All souls perished instantly from the deceleration (350g) and only fragments of human remains were recovered, to be identified by dental records and/or DNA.
A seismic event was recorded by a land station. The wreck came to rest a few miles offshore at a depth of 55m. The resultant ‘relatively compact’ debris field measured 125 x 95m. The terrain was undulating, silted and at bottom around 1m visibility. The accident occurred on 2nd Sep 98, with the FDR recovery on 6th Sep and the CVR on 11th Sep. From 'only' 55m. The FDR/CVR situation was compounded by their respective ULB broadcasting on the same frequency, frustrating efforts to pinpoint their origin, and in a state of becoming detached from either recorder. Jet-A fuel was apparent on the surface for a few hours prior to evaporating.
Transpose this scenario with the aid of the few known factors thus far in the AFR447 case, and it is fairly obvious that if we, for the sake of simplicity, take the depth of the Atlantic in the general region of the point of impact as 5500m (10 times the depth of SWR111 and hundreds of miles from land), then the debris field would be of the order of 13 x 10 kilometres.
This, in mountainous terrain, with the valleys mainly filled with pooling mud.
And that’s assuming that the acft impacted in one piece.
If it had reached terminal velocity (rough calcs according to Stoke’s Law would put the plunge at around 400~500kts depending on superstructure presentation relative to the surface) and consequently broken up on its way down, just multiply the debris field projections by the number of impact points, and compare that with the scale and effort that went into the SWR11 recovery and you’ll quickly appreciate why the French are already hedging their bets and warning that the FDR & CVR may well never be found.
The apparent lack of any appropriable seismographic event may conceivably be due to a large number of fragments impacting at different velocities, at different locations and slightly different times.
This, however, runs diametrically contrary to the hitherto lack of flotsam and jetsam on the surface. More break-up prior to impact would presumably imply more lighter debris, spread over a significant area.
In summary the rule of thumb in this contributor’s humble opinion would be that the ‘needle-in-the-haystack’ operation – on paper – would command the effort of the recovery of SWR111 raised to the power of ten. At a conservative estimate.
How far do you go? How far would you need to?
Sincerely,
PB (one who lost two colleagues in the pointy end of SWR111)
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This would explain why all three Air Data computers gave up,
In all the messages there is only one referring to the AD.
ADR Disagree. This infers that there is a fault with one AD output. How do you get to all three?
p.s. glad you said AD computors. Many posters here refer to ADIRU failures but it is only the AD part of the ADIRU that has failed, not the IRU part.