Hi BOAC Your latter point is correct to me... they "aren't" (or rather, don't need to).

You do not fundamentally fly the aircraft "differently" in each of the laws. Pull stick back, cows get smaller etc. Yes - Direct Law is a little more "twitchy", but nothing dramatic. Yes - Direct Law needs manual trim, but it tells you that on the AH in Red.

There are "various" flavours of Alternate Law, depending on "how" it got into Altn (or rather, what failed). And they are not fully described in the manuals (nor IMHO do they need to be). If this unique to Airbus? No - I tried reading up the 767 split Control Column / elevator system post the Egyptair accident, and the manuals were again vague - sufficient I would say to fly it, not sufficient to build/mend it, or investigate an accident related to it.

The main difference between the laws is what "protection(s)" are available. In that you never routinely fly to / use those protections, then life goes on as before.

Before over-analysing this accident, we ought to let the BEA analyse it, and see if the stall warnings could have been more helpful. It seems they may have been suppressed at <60K (?) which is pretty much beyond where we expect people to be relying on them, and potentially well beyond certification requirements and controllability?

Power at stall examples
 

"In June 2007 a Boeing 737-300 had an uncommanded and unrecognised autothrottle disconnect during the initial stages of an approach to Belfast Aldergrove Airport. The disconnect occurred with the thrust levers at idle and the aircraft decelerated below its commanded speed of 170 kt. At 112 kt with a 16° nose-up attitude the crew advanced the engines to 96% N1 and a rapid change of pitch to 22° ensued. The aircraft lost some 300 feet before recovering to manoeuvre speed and level flight."

Thomson Fly Pilot notes:

"The operator’s QRH procedure for upset recovery is set out in Appendix B3. The ‘upset recovery’ QRH defines an upset as unintentionally exceeding a pitch angle greater than 25º nose-up. The procedure states:
‘If needed, use pitch trim sparingly.’
The procedure continues:
‘These techniques assume that the aircraft is not stalled. A stall condition can exist at any attitude and may be recognised by continuous stick-shaker activation accompanied by one or more of the following:
Buffeting which could be heavy at times●●
Lack of pitch authority and/or roll control●●
Inability to arrest descent rate●●
If the airplane is stalled, recovery from the stall must be accomplished first by applying and maintaining nose down elevator until stall recovery is complete and stick-shaker activation ceases.’
The upset recovery procedure requires the pilot flying to carry out certain actions including:
25
Apply as much as full nose-down elevator●●
Apply appropriate nose down stabilizer trim●●
Reduce thrust’●●"


MORE DETAIL HERE:

http://www.aaib.gov.uk/cms_resources...%20G-THOF1.pdf

Isn't there an Abnormal Attitude Law as well which was frustrated in this case ?
http://www.pprune.org/tech-log/42692...-airbus-2.html

Icing, Unikely Or Not?
 

Bear,

Your quote:
From the Vasquez June 1, 2011 report update:
Just thought it would be good to point this out.

Turbine D;

Perhaps you should think twice before adding to the semantic confusion on this and other threads about 'icing'. Icing is the formation of ice due to freezing of liquid water. Transport airplanes, their engines and pitots are approved for flight in icing conditions after demonstrating that capability in extensive tests in natural as well as simulated icing conditions, and by flying with simulated ice shapes. All experts agree that these conditions do not exist at -40 °C. I am grateful to Tim Vasquez' excellent analysis of the meteorological conditions of the accident, but I understand from your middle quote, that he may not be aware of recent research triggered by events in which turbine engines suffered thrust loss flying in clouds of ice particles at altitudes and temperatures similar to the conditions of AF447. A number of publications from the Boeing stable explain the theory developed to explain the mechanism that causes atmospheric ice particles to stick to heated surfaces, such as engine intakes or pitots. Are you aware of these?

Just need to read, this one Air France 447: the facts and what's behind them
has not much to do with the BEA note.
Who are you working for Mr Learmount ... ?


STALL is a question of AoA, not pitot/static.
As long as AoA data are in the STALL range ... keep WARNING !


For now, BEA has not published anything like it.

BOAC:Fully agree!

And number 2 is that when airspeed information, something that the flight control system relies on heavily, becomes unreliable, that autotrim of the THS should drop out with the autopilot.

We won't know until we can see the plot of stick motion but it seems to me that the PF didn't know, or forgot, that when he pulled back on the stick, he was trimming into the stall. Do we know that the initial pitch excursion was the result of some action of the flight control system and/or the autopilot, or was it the result of PF action in response to erroneous indications?

TurbineD

Vasquez:

Quote: "...With a flight level temperature of -40 deg C suggested by the proximity sounding (and -36 deg C parcel temperatures) the A330 would be exposed mainly to frozen ice particles and perhaps graupel..."


and:

"...Quote: Tropical storm complexes identical to or stronger than this one have probably been crossed hundreds or thousands of times over the years by other flights without serious incident, including ascents and descents through critical icing zones in tropical showers. My original conclusion from June 2011 is still unchanged: turbulence and possibly icing creating an initial problem that led to a failure cascade..."

Here, he isolates icing as ascent and descent related.


Here, Vasquez suggests an exposure to frozen "ice particles" and "graupel".
There is no water available, and any ICE related problem would be a "packing" of the Pitot void by micronucleated ice. As Hazelnuts39 points out, a loss of power due to this phenomenon is known, particles sticking to engine parts, (including blades, I think.) Engines have anti icing.

For ICE to plug the Pitot at its orifice, ice particles would have to attach, or enter and pack, or melt and refreeze, to include a plug of the drain, which itself has a proclivity for corroded drain holes.

I believe this is the only way pitots could be plugged in the FL Vasquez is researching. This phenomenon could be eliminated (has been?) by BEA with a simple examination of leading edges of structure, inspecting for the typical abrasion of metal, composite, and painted surfaces caused by solid ice particles impacting at high speed.

That's it for me on ICE, what I think happened is Unusual attitudes caused a discrepancy in airflows into and past the separate Pitot Tubes, and causing sufficient data disruption to fault the AD(IRU). Coupled with a large turbulent flow that may have upset airflow rates, the sequence of events at a/p disconnect (and prior to) was likely the beginning of UAS. If turbulence related, there was a prior input that caused (perhaps) the a/p drop due its own mechanical limits, these limits serving to cause the drop and subsequent upset.

Again, the previous fifteen seconds to a/p drop, and the following 15 seconds seem to me to be the beginning of the accident.

unrecoverable stall
 

In the latest issue of Airbus Safety First magazine captain Rosay mentions a couple of times "unrecoverable stall"

An Airbus 330 can get so deep in a stall that you don't have any means to recover from it even if it stalls a a high level?

Glide characteristics
 

Grity, very interesting.

QUESTION: Would you say, then, that anyone with a good model of an Airbus A330-200 with the correct CG etc, could give its HS a 13° nose-up trim and thereby demonstrate its glide characteristics?

Maybe somebody could do this and put a video on U-tube?

I have heard that Rutan's first test of the Spaceship 1 concept was done this way - he threw his model off the top of a building.
It was enough to show the concept was valid.

CONF iture,

Indeed he suggests (most likely poor editing of the article) the PF initiated the climb before A/P and A/T disconnected. He should have swapped paragraphs 3 and 4 to concur with the BEA note's sequence of events:

Thanks for that. I spent nearly an hour searching for the thread in
question, search terms such as "PGF Airbus accident" and "PJ2", but no
luck. Perhaps there are external links that describe transitions between
laws and the conditions leaning up to them ?.

Something a bit more in depth than "user guide" level would be good. A
control law manual for the 330 perhaps ?...

If they didn't think it could stall, why did they build in a stall warning and stick shaker ? Why did they document it ? Why did they publish info on stall recovery procedures ?

Airbus knows, and always has, that their aircraft can stall. Airbus state, and always have, that their aircraft can stall. So where does this "cannot stall" come from, who is saying it ? Are there really actual airbus pilots (as opposed to clueless journalists etc) who believe their a/c cannot stall ? If so, the training is way more broken than even the most extreem comments on this thread have suggested.

737 (for one) does that (and the bus in direct law - see perpignan). Works really well - not. A/P trims a/c up (eg trying to follow glide slope with too little thrust), drops out at stick shaker and leaves pilot approaching stall fully trimmed up. How many then remember to re-trim ? Schipol ? Perpignan ? Bournemouth ?

I am starting to believe that from a user interface point of view, autotrim should either be always on (extension of elevator control, always) or always off. Failure to make the transition from auto to manual trim is becoming a pattern in an lengthening list of accidents and incidents.

Autopilot was out before pitch up. As to FCS, we do not know yet, and even the BEA may still be working through the data to determine whether control surfaces responded correctly to pilot inputs (and only pilot inputs) through the event.

The designers at both A and B either didn't read Langewiesche, or forgot. They try to control speed with power and altitude with pitch.

Microburst2002
Captain Rosay is a cagey old test pilot. If he says that, he may have seen indications in some of their test data pointing to that conclusion, but I doubt that AB has strayed very far from the immediate area around the stall in their test flying. It is just too risky to do deep stall work. (But see my post in the other AF447 thread http://www.pprune.org/6494757-post1415.html) He has also no doubt seen wind tunnel test results at high AOA.

But to me, the initial description of the AF447 descent seems to indicate that they could have retrimmed the THS and recovered. We will have to see what BEA says about it.

HazelNuts 39,

I am sorry if the term "icing" confused the situation, it was a word Tim Vasquez used in his report I quoted from and I didn't change it. I believe icing is when supercooled water encounters a surface and then freezes. In the case of AF447, this was not the case. There was no supercooled water involved to the best of the weather expert's knowledge.

What I was attempting to say was the aircraft passed through a cloud or clouds containing ice crystals which, when coming into contact with wetted heated surfaces, can stick and buildup. I am very aware this phenomenon can and does cause problems with turbofan engines to varying degrees depending on a particular engine design. As Boeing studies have indicated, the ice buildup can both adversely affecting engine airfoil aerodynamics (power loss) and in severe cases, damaged compressor blading (ice shedding) or even cause combustor flame outs (water extinguishes the flame).

From what has been said so far by the BEA, the GE CF6-80E engines were not affected and performed in a normal manner. However, I am not so sure the pitot tubes did, they could have indeed clogged which lead to the erroneous speed sensing and eventually the AP/AT disconnect.

Indeed there is considerable testing done during the initial development and certification testing of new turbofan engines to determine effects of ice ingestion, large and small particles and shedding characteristics. I have seen it done in person on several occasions.

As Boeing points out, it is best to avoid areas of storms where ice crystals are present as the volume tends to be unknown and onboard weather radar may not detect the presence of ice crystals at all.

I stand to be corrected on any of the above.

Law reconfiguration.
 

@Chris:

Think if one will try to flowchart all possible reconfiguration you will end up in spaghetti,
but let’s give it a try and a start, if you need some specific data (sure not knowing them all!) to assist you just PM me.

** When you call any activation of a protection a new ‘law’ then you will find out there are dozens of ‘laws’ more.
** A (like B) documentation isn’t very consistent in making difference between a protection or a ‘law’

In (autoflight or manual flight) and A/C response = commanded --> Normal Law
--------------------------------------------------------------------------------------------------------
If (autoflight or manual flight) and certain A/C protections can’t be fulfilled -->Alternate Law
Possible causes:
High speed and high angle of attack protections enters Alternative law.

ALT1 - If there are faults in the horizontal stabilizer; an elevator; yaw-damper actuation; slat or flap sensor or a single ADR or IR fault.

ALT2 - Dual hydraulic failure(low press), faults in 2 IR or ADR references, with A/P lost except with an ADR DISAGREE; In all spoilers fault; certain ailerons fault or pedal transducers fault.

Indicated by ECAM MSG
F/CTL ALTN LAW
MAX SPEED 305/.82

if auto pitch trim not available à Amber USE MAN PITCH TRIM (first 6 sec flashing) below FMA.

On the PFD specific symbols (=) and formatting of low speed information on the speed scale indicates which protections are available.
When protections are lost, amber crosses (XXX) appear, instead of the green protection symbols (=).
---------------------------------------------------------------------------------------------------------
In manual flight only and if alternate Nz law can’t be kept --> Direct Law

E.g. If all 3 ADR or IR, 3 PRIM failure; 2 Elevator fault.

Indicated by ECAM MSG
F/CTL DIRECT LAW
MAX SPEED 305/.80
MAN PITCH TRIM USE

Amber “USE MAN PITCH TRIM” (first 6 sec flashing) below FMA
-------------------------------------------------------------------------------------------
In case of all electric FCPC/FCSC failure à Mechanical Only

“MAN PITCH TRIM ONLY” below FMA

Pitch: Elevators are hydraulic centered and becomes ‘fixed part’ of THS.
Yaw: à Rudder pedals (supported with yaw damper if available)

************************************************************ *********************
Alternate Law:

. In pitch: Same as in normal law
. In roll: Same as in normal law (ALTN1), or Roll Direct (ALTN2)
. In yaw: Same as in normal law (ALTN1), or degraded (ALTN2)

. Most protections are lost, except :
-- Load factor protection
-- Bank angle protection, if normal roll is still available (ALTN1 only).

At the flight envelope limit, the aircraft is not protected:
. In high speed, natural aircraft static stability is restored with an overspeed warning
. In low speed, the auto pitch trim stops at Vc prot (below VLS), and natural
longitudinal static stability is restored, with a stall warning at 1.03 VS1g.

In certain failure cases, such as the loss of VS1g computation or the loss of two ADRs, the longitudinal static stability cannot be restored at low speed.
In the case of a loss of three ADRs, it cannot be restored at high speed.

VMO/MMO settings are reduced and A FLOOR is inhibited.


If certain values are exceeded abnormal attitude law is triggered.

. Pitch (50 degrees up, 30 degrees down)
. Bank (125 degrees)
. AOA (>30 degrees, < -10 degrees)
. Speed (>440 kt, < 60 kt)
. Mach (0.96, 0.1).

Abnormal attitude law:
. Pitch alternate (adapted Nz Law) with load factor protection (without autotrim)
. Lateral direct law with yaw alternate

After A/C recovery and until landing:
. Pitch Nz Law (with autotrim)
. Lateral direct law with yaw alternate

This thread reminds a little of the story where after paint, a pilot took off and the controls were rigged wrong...turning the yoke left, meant a right turn, and visa versa...he couldn't figure it out, and crashed.

It wouldn't surprise that a pilot trying to get the speed up, pushes on the yoke, but the fly by wire, now with reverse commands pitches up...the pilot keeps pushing forward...and at cruise speed and this condition...a 3k climb would be nothing, it would happen fast...

If the A/S tape was reading wrong as well...low speed meant high speed etc...it would all happen pretty quick..

Maybe lighting from a thunderstorm zapped the computer...

One more reason to use the radar, and have a plane that can actually get up to FL450.

Just a thought.

As far as the pilots are concerned, the most important thing to know about Alternate Law, the same as with any aircraft that has suffered damage, is to remember that this is no longer a normal day at the office and that you must bring your "A" game. The fundamentals of Alternate Law are the same in all reversions, the variations depend on which systems/sensors have failed, same as in a regular aircraft.

The computers are designed to give the pilots what they ask for in this mode - no more, no less.

No-one's disagreeing with that, but the knowledge of the different laws (or lack thereof) is not the issue in my opinion. Bad airspeed indications over water at night must be pretty close to a pilot's worst nightmare no matter who built the machine they're flying. The lessons learned from Birgenair and Aeroperu have hopefully given pilots more of a fighting chance than they had in the mid-90s, but it is just that - a chance. It is an inherently difficult problem to solve.



Why do you say that? You're taking a design decision out of context and trying to change that decision based on one accident. There are plenty of other scenarios where autotrim without A/P is a good idea (for example, pilot incapacitatation in Alt Law - the remaining pilot has pitch and trim in his sidestick hand and throttles in the other, rather than having to switch around all three).

@infrequentflyer - agree 100%

All aircraft have quirks, the A330 is no exception. I don't think it requires more training than, say, a 767 or whatever, it just needs the *right* training, and it appears that some airlines are definitely shirking that responsibility.

Pilots didn't have to worry too much about the counterweights, levers and so forth that provided artificial feel in the past, why should software laws be any different as long as the training to deal with those changes in laws is correct?

@theficklefinger - Seriously? FBW Airbus models have been struck by lightning more times than you care to shake a stick at, and very few of those even required a computer reset (I think there's a post on this earlier in the thread). The only time controls have been wired up in reverse in an A320 it was due to a maintenance error, and the pilot in the other seat calmly took over control and landed the aircraft safely. Airbus then changed the design of the connectors so it was not possible to wire them up incorrectly in that manner again.

Turbine D;

Thanks for your reply. I've nothing to add to what you wrote.

Fiklefinger may have a point here. With a blocked Pitot Tube & increase in altitude IAS increases, to the point of "indicated overspeed", even though the aircrafts actual speed may remain constant. Many years ago a B727 crashed as a result of a stall brought on by the the crew increasing pitch to reduce the false overspeed warning. They had departed with the Pitot Heaters switched off. In a conventional aircraft an overspeed is dealt with by thrust reduction (partially) or deployment of speed brakes. However 1 of the options the control laws have, in the result of an overspeed is pitch up. Maybe the cmptr did what the 727 crew did before. I understand recently a 330/340 entered an overspeed, due turbulence on the Atlantic run. The aircraft pitched up, with a "severe vertical separisation issue" on an aircraft coming the other way, even though the AB crew were pushing column full forward!! Remember, all these events occure under severe stress for the confused crew. This, IMHO is a design flaw in the aircraft.
Jumbo.

@jumbojet

I don't know how many time I can say this - the computer did not "do" anything, because autoflight was inhibited by the detected erroneous speed indication. The issue you're referring to has been documented exhaustively on this forum, and is highly unlikely to be related, not least because thus far, no indications of an overspeed indication have been reported.

Well thats what happens when you join a thread 70+ long half way through! Haveing said that though, why did it pitch up then? We all know, go above your max computed altitude at your peril! I would be very suprised if a pilot chose to climb above his/her max cruise level. Most pilots know the cost of this, even French pilots! Who knows whats in the brain of the ship & who knows it reaction to an unexpected indication, jiust ask MSN!!

Re airbus can not stall
 

I can help out here. Some time ago (1998) the chief test pilot of airbus itself,
Captain William Wainwright, is saying:

"The end result of two years work is a training
package including a video and a CD-ROM,
giving an airplane upset recovery training aid.
This package is on free issue to all our
customers, to use as they wish. However, all
members of the joint industry group agreed that
the package is aimed at preventing loss of
control accidents on conventional aircraft. It is
not aimed at protected Fly-by-Wire aircraft.
There is no need for this type of continuation
training on protected aircraft, although a
general knowledge of the principles involved is
useful for every pilot"

Source: Airplane
Upset Recovery Training Aid*

It was not the idea of airbus alone, however, on the boing page it looked somewhat different.

"Aerodynamic principles of large, swept-wing commercial jet airplanes are similar among all manufacturers. In the interest of safety, and the desire to acknowledge the commonality in recovery techniques, this article was written jointly by Airbus, Boeing Commercial Airplane Group, and Douglas Products Division. The article focuses on Airbus and Boeing airplanes that do not have electronic flight controls, commonly known as fly-by-wire. However, when a fly-by-wire airplane is in a degraded control law (mode), the recovery techniques are appropriate. Additionally, certain conditions can upset any airplane and the basic principles of recognition and recovery still apply regardless of the flight control architecture."

Source: Aerodynamic Principles of Large-Airplane UpsetsLoss of Control in Large Airplanes

speeds and angles
 

I am sorry if this is redundant. I have been on and off here and have not had time to read every single message.

In an effort to investigate the difference between the data at point 6, 2:11:40 (35,000 ft, 10,000 fpm down, AoA > 40 and pitch angle 15) and impact, 2:14:28 (0 ft, 10,912 fpm down, groundspeed 107 kt, and pitch angle 16.2) I measured the ground distance along the flight path from point 6 to impact. (I did this on the assumption that the BEA graphics are computer-generated from GPS data and are therefore precise.) It is about 7.37 nm. The elapsed time is 2.8 minutes. The average rate of descent is 12,500 fpm and the average groundspeed is 158 kt. The average true airspeed is 201 knots, the average glide path angle is 38 degrees. Assuming that the pitch angle does not deviate much from 15-16 degrees, the average angle of attack is 53-54 degrees.

Since these numbers do not match those at either the starting point or the impact point, there must have been considerable variation in between, and in particular a higher rate of descent.

While I have argued (and written) against the "deep stall" theory, which unfortunately remained untested by the crew, I am having a hard time understanding how this airplane managed to maintain this high an angle of attack for this long a time without departing into a spin. Can anyone point me to wind tunnel or flight test work relevant to transport aircraft of this configuration at extreme angles of attack? The Langley stuff I've found is all about spinning. I'm going to telephone them tomorrow.

Abnormal Attitude Law
 

A33Zab
The above has been the accepted list of "triggers" for this event, and looking at the list you would assume that either of the 5 noted conditions would be the "trigger". It now appears, if the BEA press release via Flight Global is to be believed, that if the ADR's have all disagreed, the only "trigger" depends on an Inertial upset whereby items #1 and/or #2 above are the only means of entering Abnormal Attitude Law.

Garrison
Go back to post #1396 by grity, where you will find some interesting basic concepts. Also have a look at a post by PickyPerkins
at #1394.

Perhaps the BEA will release the weight and balance numbers for AF 459 on June 1. AF 459, an A-330-203, departed Sao Paolo for CDG, and after ORARO requested, as part of its deviation, a climb from 350 to 370 and was authorized such by ATLANTICO.
___________________________
With respect to the outside air temperature at 350, I believe Vasquez as does the BEA relies on the AMDAR measurements from EU 0046, thought to be the LH preceding AF 447 by about 20 minutes. The 744 is stated as being at 10660 meters, FL 325, and the outside air temperature was -40.6C. I believe Meteo France calculated the temperature at the top of the MCC that AF 447 encountered as -64C at 2h 07. I think the outside air temperature at 350 or 380 was likely lower than -40.6C.

Turbine D

I don't understand the need for semantics in this discussion at the level of interest at this point in the investigation.

I really don't have any corrections to make either. However, AFAIK the ice crystals at high altitude do not adhere to blading (unlike low idle conditions at low altitudes in freezing rain).

I would add that some engines have been affected by the effects of probe blockage which affected the FADEC control on stall recovery which of course affects power.

AFAIK, no conclusions have yet been drawn by the BEA regarding the presence of water droplets or ice crystals on any of the systems in AF447.

However, for those that intend to pursue a loss of speed signal to the aircraft computers in their causal factors I do understand their presumptions that the aircraft might have been in a position to accumulate ice blockages in the Pitots. Why and how doesn't strike me as important right now in the early investigation. And in the final analysis, if Pitot systems were somehow affected by ice of any kind, even that is less important then to understand why the subsquent downstream layers of swiss cheese got eaten up.

Of course an upgrade of pitot systems is probably still warranted based entirely on past history.

There may be less difference than you think, and may be down to semantics and/or translation. Your first bolded statement was unanimously agreed by A & B reps (and test pilots). The second, from boeing, does not actually contradict it, and effectively says the same as Airbus do elsewhere. An Airbus in Alternate or Direct laws is a non-protected FBW aircraft, therefore, as the Boeing quote says, the same recognition and recovery applies.

That's from Airbus FCTM (admittedly an old copy downloaded from somewhere or other). Says effectively same as boeing, accounting for it probably being translated from French.

To me though, the real proof is still in the engineering - those that designed and built the buses put a stall warning system in, and I'm absolutely sure they didn't do it because it looked pretty or to get the weight up to the design spec.

PickyPerkins wrote..

and any nose down input increases the HS depth of stall.

Is the C0G so far aft (for efficiency) that it doesn't help with recovery? If so does that leave the engines as only means of recovery?

A good reference on this, which has been posted here before :-
http://airs-icing.org/AIRS_II/AIAARe...06-206-739.pdf


Err yes, but the Thales AA probe in use was known to be deficient on this type of aircraft before this event, (ref Air Caraibes for example), and the replacement Thales BA probe not as good as the best Goodrich probe - hence the ADs around the world in September 2009.

But the now preferred Goodrich probe also failed in the Guam October 2009 incident, and if you read the report and the recommendations

Unreliable airspeed indication - 710 km south of Guam, 28 October 2009, VH-EBA, Airbus A330 202

your comment probably still applies!

If you're told to pull with no fear isn't it because we protect you ?

simultaneous multiple pitot icing
 

DJ77, we'll never know for sure if this accident was caused by simultaneous multiple pitot icing or not. The RHS readings were not recorded. (And, of note, the RHS was flying the plane.) I bet Air France is a little concerned about that lack and may become more so when the next report (months off?) comes out.

Rush To Judgement
 

bearfoil, I agree with the kick some butt sentiment in a limited way. If there is a suitably guilty, proven in court, butt to kick I figure the court should administer a suitable kicking in the suitable place - although it might be more effective if the kickee were rotated 180 degrees.

Now that I've established my blood-thirsty creds I also note I did say "court". There is not sufficient knowledge for a court to act. You may think so; but, I notice you are very wrong very often. (Have you finally given up on the VS came off?)

Can we leave off the blood thirsty, please? If you have something new to contribute or if you see a discrepancy between a posting here and information we have available directly from BEA, then chime in. Otherwise you are being somewhat inurbane and outright boorish with your demands for butt kicking.

Just sayin'.

Turbine D, stand up and take a bow.

If faulty design of pitot probes are "at fault" here perhaps the radar manufacturers are also at fault for not building a radar that can detect the ice crystals by running at one of the H2O molecule's resonances. There may be conflicting frequency allocations involved. But that can be dealt with for safety, I suspect.

Regarding the probe, it appears nobody has been able to reproduce this in the lab. They cannot develop the conditions postulated to create the problem because they are so outlandish. So should they be blamed for that? Should retribution be extracted from them for that?

Please God, can we use this accident as a way to improve system safety and not enrich trial lawyers to extract "retribution?" Kick a butt is there is one clear butt to kick. Otherwise move to the real problem, making it safer.

The BEA report notes that the RHS airspeed is not recorded on FDR. So even though we know that the LHS and ISIS speeds matched again shortly after 2:11 we cannot be sure that the RHS airspeed also matched the other two. From this, many here have concluded that the PF may have working off incorrect IAS.

Of course, it's entirely possible that the RHS airspeed also matched the others. If the problems with two of the Pitots resloved themselves, why would the third not have as well?

More to the point, even if the RHS airspeed continued to differ from the others, would it continue to be displayed? Would the computer not substitute one of the other measured airspeeds for the one that it has decided is invalid? Or if it keeps displaying the invalid airspeed, would it not flag it as suspect?

Lets think about it a different way. It has leaked that the aircraft never achieved the abnormal attitudel law. For this to happen, It would seem that there was no synchronization of two airspeeds to form a "consensus" after the initial switch to ALT2 law.

lomapaseo,

Take a look at this presentation by Boeing and tell me what you think.

http://icingalliance.org/meetings/RI...ersion_nss.pdf

There would be a IAS DISCREPANCY ECAM MSG and it would be to the crew, after cross checking the different IAS, to select the suitable ADR as air data source.

What I'm very curious at is, what were showing the FD Crossed Bars (or Flight Path Director if FPV was already selected) as soon as both recorded speeds were again consistent ?

Is it possible the NU inputs were suggested by the FD ...