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AF447 wreckage found

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AF447 wreckage found

Old 27th Jun 2011, 14:06
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BOAC, if the LH narrative (p. 88 of the interim report) is taken at face value, AF447 was already in the clouds at FL350 on reaching ORARO. So on that basis, I would posit they were already in what they were in, and did not point themselves in the direction of a Cb.

And beyond that, I think we both agree that we won't know more until the full CVR comes out (though even a negative on the full CVR could be telling).

I do find it curious that the BEA dropped the LH and IB flights from the interactive, yet included flights on UN866, 90 NM to the west. Perhaps these two UN873 flights, with more detail, will re-appear in the final BEA report.
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Old 27th Jun 2011, 14:58
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Back in 2009, Vasquez created this image of what he thought a radar would show.



Source:
http://www.weathergraphics.com/tim/a...7-radarsim.jpg

If Vasquez's depiction is reasonably accurate, did AF447 try threading a needle?

BOAC, I agree that pitot icing was the precipitating cause of the upset (no pun). But proximity to a Cb with updrafts, and associated transport of liquid water into regions where it spontaneously forms ice crystals may have led to the pitot icing.
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Old 27th Jun 2011, 15:00
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I am trying to stop the growing spread of the 'urban legend' that they "flew blindly and stupidly into the mother of all CBs". As long as that remains unproven (and unposted), I am happy.
Couldn't agree more, BOAC - truly sorry that we've been at cross purposes. I feel exactly the same way. For myself, I'm sick and tired of the press and public (and most other parties involved) seeking to blame the pilots for almost every accident that occurs. Unfortunately, though, that tends to suit most of the organisations that might otherwise be held liable - especially, of course, the airline, the manufacturer, and the equipment suppliers.

There are bound to be, as always, a number of causes identified in the final report. 'Pilot error' always suits the business side best - beyond that, it will be a 'horserace in reverse,' with Airbus, Air France, and Thales all 'competing' to finish in fourth place.

As I and others have said, there are significant and meaningful chunks of flight deck comment missing from the release for some reason which may well hold an explanation as to why they zoom climbed, for example, which precipitated the stall.

I have commented in Tech Log also on the Atlantic incident in 2001 where an A340 did a similar zoom - without crew input - and its speed reduced to a very low figure too. Way to go.
Total agreement. My earlier consideration of possible, unexpected 'severe turbulence' was actually triggered by the BEA's (in my view, completely out of line) assumption that the 'zoom climb' was merely the result of the PF pulling the sidestick back. I can supply yet another example of a (quite recent, and fatal) 'zoom climb/deep stall' incident that had nothing at all to do with 'pilot error,' and was in fact caused by sudden and 'severe' turbulence:-

Because of storm cells ahead, the pilot decided to change course laterally by 20 km and attempted to climb over the storm cells. However, the thunderstorm front was unusually high, extending up to 15 km (49,000 feet). The Tu-154 entered an area of severe turbulence, pushing up the airplane from 11.961 m to 12.794 m within just 10 seconds. The angle of attack increased to 46 degrees and the airspeed dropped to zero. It entered a deep stall from which the crew could not recover. The plane crashed and burned in a field.


ASN Aircraft accident Tupolev 154M RA-85185 Donetsk

Apologies in advance if I appear to come across as unduly cynical......
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Old 27th Jun 2011, 15:09
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RWA - pleased we have an accord!

Saturn - I cannot comment on the 'proposed' radar picture - without diving into my lats and longs and trig tables,
1) I have no idea what the range scale is between the 'red' bits or what they might signify
2) No idea what scanner angle or gain is being synthesised there
3) I see no 'Mauve/purple' to indicate moderate or greater turbulence

Depending on the distance between cells that I saw I might well 'thread the needle' as you call it - normal practice if the gap is sufficient.

A pretty picture but really meaningless in real terms.
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Old 27th Jun 2011, 17:52
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A330 QRH Anyone?

I don't have a QRH available, and the nearest thing I have is the A330/A340 Flight Crew Training Manual from:
http://www.smartcockpit.com/data/pdf...ing_Manual.pdf
The procedure for Stall Recovery says:
Set TOGA thrust
Reduce pitch attitude to 10° below FL200 or 5° at or above FL200
Roll wings level
Check that the speedbrake is retracted
No mention of pushing the nose down, no mention of checking the HS trim...
It seems to me they were 'following the book', albeit somewhat nose up.
Am I missing something?
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Old 27th Jun 2011, 18:47
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Roseland
Am I missing something?
revised stall recovery procedure
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Old 27th Jun 2011, 19:42
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(The BEA summarizing seems to contain at least one error: the LH is said to be at FL 350; but the AMDAR trace says 325.)
Saturn, do you realise that FL "325" is not an available flight level for this route ?
Where is the "error", then ?
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Old 27th Jun 2011, 19:47
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Cool

Hi,

Am I missing something?
I don't think so ..
Any procedures put in force after the day of disparition of AF447 is not relevant for the discussion of AF447 case
The pilots had to work with what they have this day (procedures and training)
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Old 27th Jun 2011, 20:01
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Information

BOAC,

Your quote:
Based on what little I see so far I do NOT consider turbulence to have been a contributory factor in the accident.
Also in 10 minutes a cell can move quite a distance in relation to an avoid distance of 20 miles or so, so the question is not what 449 or IB did, but what 447 did. If I had 2 Drachma for all the different interpretations of 'weather' I have seen in my career I would be able to rescue Greece from bankruptcy.
I rspectfully disagree with your statements here, there is certainly information that turbulence and weather played a role in this accident. For instance:

Other airplanes flying within the same airspace
1. Lufthansa LH 507, Boing 747‐400, Sao Paulo‐Frankfurt, 20 min ahead AF 447, FL 350 , moderate turbulence, diversion 10 NM west
2. Iberia IB 6024, Airbus A 340, Rio de Janeiro‐Madrid, 12 min afterAF 447, FL 370, severe turbulence, diversion 30NM east
3. Air France AF 459, Airbus A330‐203, Sao‐Paulo‐Paris, 37min after AF 447, severe turbulence, FL 350 auf 370, diversion 80NM east
4. TAM Lineas Aereas JJ 8098, A330, Sao‐Paulo‐Paris 40min afterAF 447, FL 370, severe turbulence, emergency descent, flight route 120 NM east

Light turbulence ‐ briefly causes slight, erratic changes in altitude and/or attitude.
Moderate turbulence ‐ similar to light turbulence, but greater intensity. Changes in altitude/attitude occur. Aircraft remains in control at all times. Variations in indicated air speed.
Severe turbulence ‐ large, abrupt changes in altitude/attitude. Large variation in indicated airspeed. Aircraft may be temporarily out of control.
So, AF447 sandwiched between LH and IB, but closer to IB interms of time and distance, may very well have experienced turbulence between moderate and severe. Notice how turbulence got worse as time went on. However AF447 did not divert, but kept on the track towards the weather ahead. Keep in mind in the ITCZ, these storms come off the coast of Africa as individual cells, but often, as in this case very close together. As they get further off the coast, they slow down and generally combine into clusters. The cluster ahead of AF447 consisted of four distinct columns. The youngest and strongest was to the east and had fully developed, the other three were in the process of decay, the most decayed cell being the western most cell. The entire system is moving westward, but at a slow rate of speed. So the flights that diverted eastward needed to stray furthest from the planned route verses LH that diverted westward.

So then the question becomes why did AF447 not divert? A clue might be this from the crew of AF459:

The Captain of Air France, which has flown Sao Paulo-Paris the same night that the flight AF 447 recounts the crossing of the Atlantic.
It is a key witness in the investigation into the disappearance of the Air France Airbus over the Atlantic. The commander of flight AF 459, who left Sao Paulo on Monday, June 1 at 0:10, French time, on board a AirbusA330 similar to the aircraft, which disappeared, wishes to remain anonymous. But he remembers precisely the conditions encountered [that night].
The route earlier in the flight AF 447. Under this pilot, the weather report that day of major cloud masses in the pot black. “The satellite maps indicated a thunderstorm but nothing alarming, he says, they are very frequent in this region.” Once in the intertropical convergence zone, the crew increases the “gain” of his radar, i.e. its sensitivity.
This manipulation can make reading the screen, which is polluted by many unnecessary details, but enhances the reliability of data on clouds. “This manipulation allowed us to avoid a big cloud mass that we would not have identified with the radar in automatic mode.”
According to one of its two co-pilots, “the cloud mass was difficult to detect because there was no lightning.” The flight AF 459 to make a detour of 70 miles or 126 kilometers, while the flight AF 447, spent twenty minutes earlier, to lead through this area, added the officer. His captain did not want to confirm this information.
Another clue as to why might be this:

Air France is reviewing crew training, use of weather radar and the availability of meteorological information for pilots following the loss of flight AF447 over the South Atlantic last month.

Chief executive Pierre-Henri Gourgeon disclosed the measures a week after investigators divulged details about meteorological conditions at the time of theAirbus A330's disappearance, and the course deviations performed by other aircraft in the vicinity.

In a transcript published by the airline after he spoke to a French newspaper, Gourgeon said there was "never any arbitration" between safety and economy and highlighted operations during weather as an example.

"For example, it's written down in black and white that, when there are storms, you go around them," he says. "There is no question of saving on fuel. Pilots are totally free to choose their route."

One of the aspects of the investigation is the choice of flight track by AF447's crew. Investigators have stated that "several" other flights - ahead of, and trailing, AF447 at about the same altitude - altered course to avoid cloud masses.

These flights included another Air France A330 operating the AF459 service from Sao Paulo to Paris. Gourgeon says this crew crossed a turbulent area that had not been detected on weather radar and, as a result, increased the sensitivity - subsequently avoiding a "much worse" area of turbulence.

"Flight 447 didn't have the good fortune to encounter that first warning and may not have been able to avoid the second very active storm," adds Gourgeon.

France's BEA investigation agency says the crew of AF459, which had been 37min behind AF447, detected echoes on the weather radar which "differed significantly" depending on the radar setting.

The crew initially chose to deviate 20nm to the west but the radar then showed an extensive squall line which led them to deviate to the east by 130-150km (70-80nm).

"On the strength of that report, we are going to review the way we use radar," says Gourgeon. "Whether or not that was the cause of the loss of flight 447, we have to examine every factor and improve all of our procedures and rules."
So, was weather a factor? If you think in terms of likelyhood, possibility or even probability, IMO, it will be a factor.

Your quote:

I am pretty certain "the aircraft is at fault" since I believe if the pitots had not failed the accident would not have happened, nor, I personally believe, would it with iced pitots with a 'conventional' FCS, but am keeping an open mind on the rest
Interestingly, four of the five planes that night were Airbus. I wonder which brand of pitot tubes the other three Airbus planes had where pitots didn't fail? Could it have been because of the particular pitot brand in use or because of weather avoidance by diversion from their intended flight path?

Not trying to change your mind, just some information to think about...
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Old 27th Jun 2011, 20:29
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GY, in trying to parse the points in the closed thread about stall procedures, I arrive at this yet again. (It seemed to discuss A320 procedures. Hope they are close enough for comparison).

IF you are trained to respond to stall warning with the idea that the stall warning means
"do something or you'll stall" *

THEN you may respond differently if the stall warning is actually telling you
"you are stalled, do something!"

The 5 deg nose up + max power seems like a pre-stall avoidance maneuver to me. (10 deg nose up at alt < FL 250)

EDIT: let me explain why I say this. It makes good sense to begin your action before you stall. If your AoA is close to stall, that's a good time to be warned. The system is designedto warn you for a very good reason: better to get ahead of the stall and fly the airplane out of that condition that to try to deal with being stalled.

While 5 deg nose up max power per that procedure (alt > FL250) would hopefully prevent (or clear, if 16 deg nose up caused it) the stall and not result in another one, a nagging thought crosses my mind.

If that attitude and power combination were sustained for too long, would you not eventually reach the altitude limit and then stall for a different reason? (Not saying this happened with 447, based on the info to hand, but it's a risk if your stall recovery at high altitude results in a climb, with airspeed limits high and low slowly converging ... )

Granted, once recovered from stall (or even approach to stall) one then works to restore original airspeed, course, and altitude ... gently, I presume.

Last edited by Lonewolf_50; 28th Jun 2011 at 14:14.
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Old 27th Jun 2011, 21:44
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So noted. Thank you.
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Old 27th Jun 2011, 22:02
  #1892 (permalink)  
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Turbine - I accept 'weather' was a factor, otherwise the pitots would not have iced up! Moderate turbulence should NOT cause an accident.

What your table of routes shows, interestingly, is that 447 diverted the correct way - west, where turbulence appears to have been 'moderate' which has NO EFFECT on aircraft control. In addition, a 12 degree left may well have placed them in the same clearer airmass that the LH found (at 10 miles).

But it all proves very little, except that going east appears to have been the worst decision, and the further east you went the worse it got. The 'radar' quote is a sensible action by AF (which of course they should have taught from the beginning)

Still no-one can explain the reason for the bizarre pitch programme these aircraft appear to have. I would really like to see the RH stick trace (assuming it is recorded).
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Old 27th Jun 2011, 22:12
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SaturnV; BOAC;

The Tim Vasquez radar simulation image unfortunately had incorrect position information plotted on it.

An enlarged portion with the ORARO and TASIL waypoints added, along with a scale, some timings and the 0210 upset position is shown below. As BOAC has already suggested, the crew appear to have been "threading the needle", and reference was made to the turbulence experienced passing ORARO.



You can argue over the simulated paint colours, but the picture of what was happening should be pretty clear. In my opinion, they were not in "severe turbulence" - more like "light chop" with the occasional "bump".
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Old 27th Jun 2011, 22:31
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BOAC - I agree the direction to go at that time was to the West although later on it was to the East. Actually, AF459 started to divert to the West, but then decided the East way around was better.

I really think that AF447 didn't change that 12° from their planned track until they were very deep into the weather and less than 40 km from where the plane hit the sea. The 12° put them on an almost north track.

As far as what causes the subsequent pitch up event, it is a mystery to me with all of the complexities of the FBW logic and computers.
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Old 27th Jun 2011, 22:41
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GerardC,

From Annexe 1 of the first interim BEA report.

Dans la nuit du 31 mai au 1er juin, un avion équipé du système AMDAR a suivi une route semble-t-il similaire à celle du vol AF447, passant au voisinage du même amas orageux, environ 30 minutes plus tôt, au niveau de vol FL325. Cet appareil a transmis uniquement des mesures de vent et température.
[^^^ p. 91]

The flight is identified as EU0046, flying at 10660 meters, FL325, outside air temperature -40.6C, in light winds. and those measurements were recorded at 01h44.

Back in thread one, the conclusion among posters was that EU0046 was the Lufthansa, and its true identity had been withheld for proprietary reasons. The 30 minutes more or less is actually closer to 20 minutes, as the 01h44 time for the data point would indicate. AMDAR was taking a measurement every 7 or 8 minutes, and I believe the 01h44 point was the one nearest AF447's 02h10 position.

Last edited by SaturnV; 27th Jun 2011 at 22:58.
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Old 28th Jun 2011, 00:09
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Cool

Hi,

It is essential to keep the standard high nothing can be neglected
it is not a kindness to overlook slackness or mistakes, it is really great cruelty to do so cruelty to wives and relatives of the man you let off and his shipmates and to yourself.
There is no margin for mistakes in submarines; you are either alive or
dead'!
These words, spoken by Admiral Sir Max Horton when Flag Officer
Submarines in 1941 to all submarine officers and men in Malta, carry a universal truth for all mariners, not just submariners.
Methink this can also apply to the airliners pilots
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Old 28th Jun 2011, 21:11
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Roseland: from your link


STALL RECOVERY


In alternate and direct laws, an aural stall warning “STALL, STALL, STALL” sounds at low speeds. Recovery is conventional. Apply the following actions simultaneously:

·

Set TOGA thrust
· Reduce pitch attitude to 10° below FL200 or 5° at or above FL200
· Roll wings level
· Check that the speedbrake is retracted



I don't know if this has since been revised, (2005) but I am not sure I'd have listed them in that order, particularly since the potential pitch up moment from TOGA can interfere with nose attitude reduction.

Granted, engines do take time to spool up, so perhaps that order listing, since one ought to be working it all at once, ends up with a nose lowered, wings rolled level, and power arriving on time to get the most thrust one can, and clean up the bird comes last. (Fly/configure, correct order).

As I suggested above, this procedure far more closely resembles a response to stall warning, which is given at an AoA before stall, by design. Follow the bouncing ball ... as the pilot continues with the stated procedure ...
  1. Below FL200 and in the clean configuration, select Flaps 1.
  2. If ground contact is possible, reduce pitch attitude no more than necessary to allow airspeed to increase.
  3. After the initial recovery, maintain speed close to VSW until it is safe to accelerate.
  4. When out of the stall condition and no threat of ground contact exists, select the landing gear up.
  5. Recover to normal speeds and select flaps as required.
  6. In case of one engine inoperative use thrust and rudder with care.
The aural stall warning may also sound at high altitude* where it warns that the aircraft is approaching the angle of attack for the onset of buffet.

* = this passage is consistent with the idea that the initial procedural steps are tailored to a low altitude procedure response to a stall warning in alternate or direct law.

{Proceeding with high alt stall warning }

  1. To recover, relax the back pressure on the sidestick and if necessary reduce bank angle.
Once the stall warning stops, back pressure may be increased again, if necessary, to get back on the planned trajectory.
Would be good steps to recover from a stall as well, except "if necessary, reduce bank angle" seems redundant. If stalled, or darned near, reducing bank angle is another way to reduce stall margin.


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Old 28th Jun 2011, 22:41
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I think it worth remembering the difference between recovering from an incipient stall and a developed stall.

Forgetting power changes which take time to attain ...

If the incipient stall is caused by too high an AoA, lowering the nose will bring about a recovery. If the stall is due to a low airspeed, say after a zoom climb, a moderate amount of nose down may be required.

Once that stall has developed, a considerable amount of nose down will be required to reduce the AoA.

It strikes me that +5 degrees NU and TOGA does not cover all eventualities.
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Old 29th Jun 2011, 00:54
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SaturnV; BOAC;

The Tim Vasquez radar simulation image unfortunately had incorrect position information plotted on it.

An enlarged portion with the ORARO and TASIL waypoints added, along with a scale, some timings and the 0210 upset position is shown below. As BOAC has already suggested, the crew appear to have been "threading the needle", and reference was made to the turbulence experienced passing ORARO.



You can argue over the simulated paint colours, but the picture of what was happening should be pretty clear. In my opinion, they were not in "severe turbulence" - more like "light chop" with the occasional "bump".

That is quite interesting when added to this below, I read TV's update about the AC position from his site....

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Old 29th Jun 2011, 04:20
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EGMA

I think it worth remembering the difference between recovering from an incipient stall and a developed stall.
I think you're exactly right there, EGMA. Basically pilots appear, until recently anyway, to have been advised and trained only on 'stall avoidance,' not specifically on 'stall recovery;' and also, apparently, to give at least equal priority to 'maintaining altitude,' rather than concentrating on getting the nose down.

The only 'good news,' though, according to this article covering a meeting that took place this year, is that both main manufacturers, and presumably the airlines too, appear finally to be well aware of the need for a 'rethink':-

"Recent crashes linked to stalls include that of the Colgan Air Bombardier Q400 on approach to Buffalo, N.Y. (2009); Turkish Airlines Boeing 737-800 in short final for Amsterdam (2009); West Caribbean Airways MD-82 in Venezuela (2005); Thomsonfly Boeing 737-300 near Bournemouth, England (2007); and XL Airways Germany Airbus A320 off the coast of Perpignan, France (2009).

“Most approach-to-stall incidents and accidents occur with sufficient altitude available for the recovery,” Boeing Senior Safety Pilot Mike Coker told delegates at the Flight Safety Foundation’s European Aviation Safety Seminar in Istanbul this year. “Incidents progress to accidents when the crew fails to make a positive recovery after the stall warning occurs.”

"Flawed training is partly to blame, he asserts. Approach-to-stall training is typically conducted at simulated altitudes of 5,000-10,000 ft., but many stalls actually happen much higher. In the case of AF447, stalls occurred at 35,000 ft. and 38, 000 ft., respectively. That has important, negative implications, Coker concludes.

“Recovery stresses an increase to maximum thrust and recovery with minimal altitude loss,” he says. Therefore, “students try to minimize the nose-down pitch change while engines spool up.”

"To make matters worse, engine margins at high altitude are much smaller than at lower flight levels, where pilots can count on a much greater response to power increases. Also, Coker says, “it is probable when pilots remain on a particular model for extended periods of time that their exposure to approach-to-stall indications and recovery occur as infrequently as once in a decade,” when stall exercises should really be part of recurring training. He stresses that training should focus on correct procedures, reducing the angle of attack and appropriate energy awareness, and not so much on minimizing altitude loss.

"Airbus and Boeing have worked together to devise new procedures for stall recovery that emphasize angle of attack rather than preserving altitude."
http://www.aviationweek.com/aw/jsp_includes/articlePrint.jsp?headLine=null&storyID=news/awst/2011/06/06/AW_06_06_2011_p36-330706.xml

I think that tends to confirm my earlier speculation that the blame for this accident is likely eventually to be spread four, or possibly five, ways - in no particular order, the manufacturer (extensive instrument shutdowns, plus the currently-inexplicable behaviour of the THS), the airline (inadequate training and undue emphasis on 'conserving altitude'), the pitot-tube supplier (given that low speed indications may have triggered the stall warnings even though true airspeed may still have been adequate), the pilots, and the weather.

The only 'good news' is that the industry as a whole seems already to be reacting to the 'lessons' of AF447 and other similar accidents, not just waiting for the BEA to produce its report.
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