Hard data
 

I imagine they are responding to some political as well as industry pressure but also trying to get all of their ducks in a row for the investigation. Every scrap of Mx, crew training, ops manual, everything. I do not understand a partial non transcript release unless some one said "just give me something to keep them off our backs for a bit". I would find it hard to believe that the data they had did not tell them the bird was down.

I saw a note above about two sources of lightning data. I'll dig into the NASA site tonight to see what data they have.

It doesn't seem bizarre to me at all. Giving met PIREPs of severe weather conditions that could affect other aircraft (turbulence, ice, etc.) should not only be considered a professional obligation, but mandatory in some during some ops, including crossings.

This ACARS message from the AF pilot that reported they were experiencing "hard" turbulence came 10 minutes prior to the auto-ACARS mx messages was one of the first things brought to light on this thread which quickly drifted off into lightning-and-techie talk with great abandon. This info isn't "new", and it's easy to imagine where a bad situation got worse with regards to turbulence and convective activity if their hands got full.

If the aircraft had slowed to Max Turb Air Penetration speed, someone else pointed out that at 35,000 with it's probable loading at that point for an 11 hour flight there existed approximately 15kts between Max Turb speed and clean low-speed cue, and only 25 kts between Max Turb and Low Speed buffet. NOT a good place to be in with anything more than moderate turbulence.

I assume the pilot (if he thought the turbulence severe enough to report it) would also have slowed to Max Turb Air Penetration Speed so things on the aircraft didn't begin to break, which puts it closer to the low speed buffet boundary and at FL350 with heavy weight, unfortunately it becomes more difficult to accelerate out of a gust/shear/convection-induced deteriorating low-speed condition due to relative-reduced engined performace.

Trying to maintain q-corner limits at high altitude while experiencing severe turbulence and updrafts/downdrafts of varying amplitudes can be an impossible situation for the A/P, or the pilot when the A/P disengages due to an exceedence of one of it's pitch/roll/etc parameters. What I gather from the Airbus drivers here, an out-of-parameters A/P disengagment such as would happen if the aircraft were being pitched or rolled past A/P limits will revert the flight controls to Alternate Law, which means hand-flying with no FBW stall protection or limtiting to half/low bank even at FL350. Please correct me if I'm wrong.

The greatest danger of high altitude flying ANY (Airbus, Boeing, whatever) aircraft through severe turbulence isn't that the aircraft will break up and lose control, it's that it will lose aerodynamic control and perhaps be impossible to recover from if it begins breaking on the way down or can't exit the severe conditions. Then the issue of engine-flame out looms large. In jet-upset incidents, engine flameout can come early and without engines electrics and pressurization are also suddenly added to the largest problem of re-gaining and maintaining aerodynamic control.

The fact that there were reports that little or no lightning was detected in the cells the flight track was shown going through or near points to the worse possibility it may have entered an area of developing cells which are where the most severe updraft and airmass convection is taking place, and least detectable moisture for the radar to paint. Aircraft have deviated themselves into a corner this way when snaking their way between cells and into "soft spots" and finding a developing cell instead of avoiding the entire area because it's too dynamic and unpredictable, or not visible due to it's imbedded nature or at night.

Mature and dissipating cells emit the most lightning, and attempting to (or inadvertantly) flying above a developing cell is a non-option, since the updraft turbulence rises to a mile or more above it's visible top.

Electrical loss?
 

Good point "Lost in Saigon". "Catching the cabin" in say, a jet upset would indeed cause an unpleasant cabin vertical change down low. (Don't ask how I know.) (catching the cabin that is, not an upset!)

I was an early generation bus cpt (A300/310 some of the first of the long series of electric jets by bus.) The radars in the 90's we had were useless for a time in auto. A declutter mode of some type would see a huge red cell and erase all but the worst part. Several of us penetrated huge cells, so everybody started flying in manual until, a year later, a new "load" showed up, and the problem mysteriously disappeared. I object to the secrecy and stealth of aerospace companies, "finishing" the design in the field by slipping new software loads into the fleet without line pilot and union input. Just denoting a revision is not enough information in my opinion.

It was quite common for us to dispatch with an inop generator or APU. The big concern was that our APU's really weren't that great, so the specter of possibly tripping the yaw damper off was real in some scenarios.

This means that if the yaw damper cannot be regained, that, to avoid losing control in wicked dutch rolls, you had to descend and slow down pronto, or else go into combat with the roll spoilers to keep it right side up (not really a line pilot skill?) Not a nice thought threading a squall line at night after you've just been blinded by a huge flash. Could really put you in peril.

To A330 drivers: I know it's unlikely, but If both gens pop off the line due to a strike, do you have something analogous to our aux green system gen? (off of hydro) Will it cover buses for yaw damper and radar?

Thanks

Crunch

Absolutely - but I would tell Air Traffic Control this. Not operations/my company. My company is (i wouldnt say not going to but very improbable) unlikely to ring up British Airways, KLM, Air France United, etc etc etc to advise them individually of turbulence enroute.



As an aside, my post and capt playstations post are referring to the rumour that Air France Ops were ACARS' a report on turbulence - NOT Air Traffic Control. So far nobody appears to have verified where the msg was addressed to. Telling someone at my company is the last thing on my mind whilst flying an aeroplane through presumably moderate to severe turbulence. Trying to type it wouldnt be much fun either.

The speculation on ACARS seems founded on far too unreliable information.
L'Express and Le Figaro (see Les navires brésiliens s'approchent de la zone du vol AF 447 for example) are citing some anonymous source denying that there was any loss of pressurisation message. In other words, concerning these messages, given that different sources are giving opposite statements, we simply know nothing at all. I know that it is a rumor forum, but when the information available lets you with a 50% chance for one thing and 50% for the opposite, there's not much rumor you can build from that (sources citing a depressurization and sources citing no such messages seem equally reliable a priori (maybe all equally absolutely not reliable) given that they come from major newspapers)

I don't see why Air France should publicly release the detailled sequence of ACARS messages, it seems inappropriate to throw this information out now which belongs to a preliminary report from the BEA later (and given how Air France screwed it up by initially speculating about lightnings, it's no wonder that they are a little bit more careful now). I do not see why this should be interpreted as "hiding" something, it seems professional and responsible, doesn't it?

Lots of reports about the Radar possibly being unserviceable. I don't know about the Airbus, but on our Boeing aircraft, if the radar is unserviceable, it tells you so (in the form of various messages on your displays .. e.g. Antenna Fail, Weak, etc)... and ACARS registers this, sending a message via VHF or SATCOM to our maintenance centre.

If the Airbus is the same, and the radar failed, I'm sure it would already be public knowledge.

I have no doubt that the crew would be intending to advise ATC since their next reporting point wasn't that far away, and perhaps they found themselves too busy dealing with increasingly averse conditions in an extremely dynamic weather situation. Perhaps AF SOPs require they notify the Company of adverse conditions, especially if there can be sick passengers, damaged food carts if they aren't secure, or whatever.

Whatever the reason, I find the notion that AF is making up fantasy messages ludicrous, and there's nothing "bizarre" about it. In fact, if it helps shed more light for investigators, it was a very pertinant and timely message that may dissapoint the spark-chasers playing Electrical Sherlock Holmes here and conspiracy theororists, but may point the most direct way to the non-complicated truth.

In a case where a reliably-designed aircraft quickly quit flying, perhaps more people should be spend some time becoming versed in high-altitude aerodynamics of jet aircraft and upper level atmospheric conditions where they fly, and less time following and dissecting electrical schematics. If you don't fly up there, for a first lesson go stand and balance on a basketball and you'll get an idea of what an airplane does on a good day, let alone when things get rough. Of the consiracy theories......no comment.

As to the comment in post #808, perhaps a date joined cutoff?
 

Those who are questioning the AF crew's ACARS message to flight ops:

HF communication is often degraded within hundreds of miles of an active storm cell let alone being right on top of one. Over the ocean there is no VHF communication, which has the advantage of being less prone to the electrical arc noise that lightning produces. An ACARS communique would be the best way to pass along this information.

>> Barbies Boyfriend "Is there anyone on here with intimate knowledge of the A330 structure that could refute this? Is it a particularly 'strong' a/c, like the Bae 146 for example? I suspect not."

Being 'particularly strong' is not comprehensive insurance against structural damage / in-flight break-up in an encounter with exceptionally severe turbulence, or, if mis handled within severe turbulence.

There are two examples of "strong" aeroplanes breking up that spring to mind, both occurring in 1966.

03/05/66 - BOAC Boeing 707-436 broke-up in flight and crashed near Mt Fuji, after a violent encounter with turbulence (mountain lee waves) that imparted structural loading significantly in excess of the design max.

06/08/66 - Braniff BAC 1-11 203AE broke-up in flight and crashed after traversing a strong squall line shortly after departing Kansas city. Subsequent investigation into the accident determined that the a/c would have to have encountered a gust in excess of 140ft/sec. at an upward angle to cause the catastrophic failure of the tailplane that was determined to be the trigger to the break up.

I am sure that you will agree that both the 707 and 1-11 are 'strong' aeroplanes, and having personally accumulated a significant amount of hours on the 1-11 I can attest to it being an exceptionally robust piece of equipment, however, I was fortunate never to have experienced the absolute upper limits of that robustness.

Think I'd rather get to a smooth weather free spot, have the aircraft under control, before advising ops I have a broken cart or sick passengers, or flying through hard turbulence.

Something about aviate, navigate communicate rings a bell.

Who knows maybe they did get to a relatively clear area - but this is all going off on a tangent - nobody knows where the msgs where sent, and what the wx situation was when they were sent.

The final message was "advisory regarding cabin vertical speed". Everyone seems to be making false assumptions of what this means.

Funny my maintenance notes and vacbi make no reference to any such ecam msg.
Cabin vertical speed indications can pulse when the rate is >1800 ft/min or <-1800 ft/min.
An advisory regarding cabin pressure would make more sense.

Do Satcom voice communications suffer similar degradation in these conditions? If there was any sense of urgency, I'm sure I wouldn't be tapping at a keyboard for several minutes :bored:

@NSEU:

No not from lightning, but SATCOM is known to unreliable when the aircraft is pitching about from any turbulence encountered. Did this aircraft have SATCOM voice capabilities? My first thought would be no as it is not common.

Typing an 80 character message on the FMS for ACARS transmission takes me and crew about 30-40 seconds.

Ahh yes, our infallible satellite tracking/transmission/receiving systems.

You do realise how often up/downlinks to/from satellites drop out because of things like storms, don't you. Let's just say they are not as reliable as you would love to think, especially as to get a signal from A-B can mean a few "jumps" from satellite to ground station and back before it reaches it's destination. A good storm in the vicinity of any of these up/downlink stations means no signal, as I'm sure we have all seen with TV signals.

Just because a GPS works in an aircraft when the weather is good does not mean it is possible for the system to be 100% reliable, and that is something anyone who has used such a thing or has any knowledge of sat systems knows.

I wonder if this tragedy might convince at least some of the many pilots who fly around in the cruise, sometimes at night or in IMC, in 'TERRAIN' mode that it's really not a good idea? (...and those trainers who teach this practice?)

Mods, I appreciate that you have had a gigantic task deleting posts on this thread that don't pertain to this subject, (as you did my earlier post on this subject), and I appreciate that over the sea, the AF crew would definitely not have been using this mode.

However, more than one person has suggested the possibility that the AF aircraft entered an area of severe turbulence where for whatever reason, the radar returns did not show them how serious the weather immediately ahead of them was.

Pilots who fly along in TERRAIN mode, relying on the other pilot's display for weather radar returns, in my opinion at least, are throwing away an important 'last slice of cheese' in Dr James Reason's model.

Every one of the professional pilots posting on this thread is doing so hoping we can come up with some plan to ensure something like this tragedy can be prevented in the future. My comment about the (I think ill-advised) prolonged use of TERRAIN mode is made with that in mind.

I don't know about your acars, but mine
 

has a nifty little feature

position

wx...including ice, turb, other...just highlight and enter...

and takes about 10 seconds or less to send a pirep...and if one guy is flying witht the plane on autopilot it doesn't take long for the other guy to send a message...perhaps hoping that OPS would send back some knowledge like: company reports ride 50 miles west good

Having been out of 'the game' for quite a while, and having only ever operated 'older' types, I am not au-fait with the types of wx radar currently in use. An issue that we used to endure with the old 3cm band and to a lesser degree the 5cm band was that if attenuation due to precip was sufficiently great, it generated a contour hole or suckers gap on the display by effectively supressing the return from any convective cells immediately behind the area of high precip and thus potentially lulling the uninitiated into a false sense of security.

Has modern equipment eliminated or reduced this phenomena?

I ask only simply because with avoidance being the name of the game, there would surely be some mitigating factor why (IF in fact they did) the crew attempted to traverse a CB? The obvious reason could be that they simply couldn't see it? There will be a myriad reasons as to how one could lose wx radar, and I am not at all qualified to speculate re the electrical side of what could possibly go awry, but would appreciate a head's up from those significantly more informed than myself.

SpaceMonkey wrote:

That's not quite what the Figaro report says:

"-Paul-Louis Arslanian, interviewed on the TV France2 news program ... also stated that to his knowledge, there was no automatic message regarding depressurization, contrary to what was reported in La Point on Tuesday."

Arslanian is the head of BEA, the French air accidents investigation bureau.

AGB

Air Traffic "Control" in that area? HF! 20mins spacing with same M-number! Anachronism! That's why all smart pilots northbound ask for max FL within Recife (Radar), because they won't get FL-changes from Sal or Dakar within the next 3 hours or so. As AMF correctly posted: Here you are, heavy at maxFL, in the coffin corner, close to low and high speed limits. If you get positive windshears/updrafts, Auto Thrust/Auto Throttle will reduce power. In a strong positive shear that might not be enough. The airplane enters into overspeed. At about 6 knots (?) in the overspeed regime, the Auto Pilot disengages and overspeed protection mode let's the airplane climb to avoid a further possible destructive speed increase. Normally, when airspeed reduces below "barber pole", the auto pilot should be engaged again (FL-CH/Open-Descent), and will smoothly descent again. Airbus pilots should know this ( is this trained by AI and AF?).
If you decide to fly manually- still slightly in overspeed- sidestick inputs (e.g. down) are restricted, until you come out of the overspeed range. Manual flight at that altitude, may it be with a Boeing or Airbus, is never an easy task and not really recommended.
If the pilots decide to give a sidestick-down-input still in overspeed, to descent back or to reduce pitch, the manual inputs are dampened, until the aircraft comes out of overspeed. Coming out of overspeed, the (now not any further restricted) input might be too large, resulting in possible minus-g , and possibly many hurt passengers, as has happened before in incidents. Structural damage might be possible, depending on g-force.
Let's hope they find the Red Box(es).
Be safe.

AGBagb, indeed I was going to post this, since I missed at first that the source was actually the head of the BEA.
He declared that "to his knowledge" there was no ACARS message about depressurization, but I would trust his knowledge, since he is at the head of the bureau responsible of the investigation, more than Le Point, which is a newspaper.
The point is: different ACARS messages are discussed here, but it seems to me that the only fact really confirmed by the BEA is that there were some ACARS messages. All the rest seems to come from newspapers. Do we really know that there was an ACARS about the autopilot being disconnected, what are the sources for that, beyond some journalist referring to unnamed sources?

Paul-Louis Arslanian also declared that the preliminary report shouldn't be expected before the end of June, and before that I would guess that the content of ACARS message will remaing pure speculation. Paul-Louis Arslanian also said that the current phase of investigation was consisting in sorting out the ACARS messages and working on their chronology - you wouldn't expect an investigation bureau to release details about some data they're still working on.

I also note that it was often reported that he said that "the flight recorders might be never retrieved" and many people use this citation as a way to feed conspiracy theories, but this was taken out of context. He said that there was no way to know for sure whether the flight recorders would ever be recovered, because no attempt has ever been made to find flight recorders at the potential depths found in this area. Quite a different statement.

Respectfully...
 

Several people have asked why a malicious act has not been mentioned - much - as a possible cause.

First, because the only hint of it was a single bomb threat - against a different flight - in a different city - two countries and 1000nm away - 3 days earlier.

Second, because there was a clear and obvious threat to the flight from the tropical storm line across the planned, reported and airway-defined flight route - and close to the wreckage site.

If someone walks into busy traffic and falls down dead, the general response will be to try and figure out which vehicle hit him - not look for a possible sniper on a surrounding building. What are the odds?

Third, because there is not much that pilots can do, outside of barring the cockpit door, against terrorism or a bomb that got through security. A pilots' forum is naturally going to focus on the things within their speciality and experience that could go wrong and could be fixed in future. Procedures, skills, planning, equipment, and aircraft design.

@PJ2: I'm not sure why you are so doubtful about the route of flight as plotted against the weather charts. It was the route planned, it followed an airway, it was confirmed en route by the aircraft reporting INTOL and expecting TASIL in 50 minutes, on that airway, and the wreckage is fairly consistent with an extension of the line INTOL/TASIL, allowing for wind and other drift. It is possible that the aircraft diverted, or even turned around. But there is no evidence of it, and the other evidence is in favor of the plane following the route as planned. Best evidence rules.

On the subject of lightning, yes, The Weather Channel did check 2 lightning plotting networks which both recorded no strikes near the AF447 presumed flight path. At the same time the meteorologist also said that lighting bolts can follow CB anvils up to eighty miles horizontally (in his experience) - and that the networks occasionally miss strikes. So it is absence of evidence, not evidence of absence. Not persuasive either way.

Lightning data
 

Data from the Tropical Rainfall Measuring Mission (TRMM) spacecraft Lightning Imaging Sensor. I have not caught the Wx channel sources in the last half hour so don't know who they are quoting. Correction, caught it, source World Wide Lightning Detection Network. The data below shows none near the area. I looked at prior and post date also, same. But here could be gaps.

Lightning and Atmospheric Elelectricity Research at GHCC Data source

Lightning and Atmospheric Elelectricity Research at GHCC Data

A very reasonable post, Dan.

I fly with the latest radar units, dual installations, pulse Doppler capability, lightning detection, vertical slicing of the target, and so forth. With a cell of sufficient size and water content, however, such as those present in a well-developed line along the ITCZ, attenuation is inevitable, at least as far as I know. The tell-tale radar shadow behind the scan is a place most of us fear to tread.

In our experience, a thorough weather brief from a competent dispatcher, an appropriately cautious flight plan routing, even at the cost of precious extra fuel, plus the very recent addition of an in-cockpit internet connection that provides us near real-time satellite and radar composite snaps of severe weather areas, has proven most effective where avoidance becomes key.

That is not to say Air France does not have this already in place. One can only speculate at this point.

QFA/AFR ADIRUs
 

This equipment is selectable SFE on A330.
QFA : Northrop/Litton
AFR : Honeywell

RE: Manual report of "hard"(trans?) turbulence
 

Some companies require a position report sent manually to Ops, every so often(e.g. every 3-4 hours), in addition to ATC positon reporting. Fixed format, with spaces for wind/temps, and toggle-able WX condition:

SKY: CLEAR/SCATTERED/BROKEN/OVERCAST/UNDERCAST/IMC

TURBULENCE: SMOOTH/LIGHT/MODERATE/SEVERE

If this was their practice, then it wouldn't be execptional, just routine....

There is an AF pilot in one of the papers today claiming it "has to have been" a bomb, because "I have been flying these aircraft for 10 years and a lightening strike would not bring one down". He also mentions the bomb threat received a few days before which caused a 2 hour delay whilst the aircraft was searched, although he acknowledges that this was on a different route. The pilot wished to remain anonymous - I wonder if that is because of the airline's previous MO for dealing with pilots who speak against the party line following an incident, or if the paper is just making the whole thing up.

Either way, as has been mentioned elsewhere on this thread, the airline were unusually quick to come out with a likely cause IMO.

pattern_is_full;
I'm not convinced there is any such thing as "best" evidence, yet - that's my main point. I concur with all your points but that doesn't yield an accurate position - it only surmises.

The point regarding the routing is minor but the claim of the Vazquez preso for example, is that the route depicted IS the route taken and it's not necessarily so. He himself cautions that all positions after INTOL are "extrapolations". Videos and animations are very powerful tools these days but can be quite incorrect depending on a number of factors. The Vazquez animation is very good as is his analysis and may turn out to be highly useful if not accurate but we should not permit ourselves to assume that such is the case at present, at least not without supporting data. We do not know where whatever-happened-to-the-aircraft, happened. The unreliability increases with time after the last position report of course, but you knew that... ;-)

In the end we may not have the luxury of much data and will have to draw conclusions based solely upon what we are seeing today. I truly hope that that does not turn out to be the case.

Normally (over land or closer to land), we would have a wealth of other information such as radar/transponder plots and ADS positions (in areas so equipped). We would have ATC records and we have always had an accident site. The evidence (this, the ACARS and anything else), is so thin that it is important to verify all of what is available as strongly as possible.

That's all...I realize and understand the kind of informal rule-making regarding evidence that's going on at present. In the end it may be all or partially correct but at the moment no one can say. At the same time many here and elsewhere are drawing conclusions anyway. Go figure.

With such little evidence, the extreme desire to determine what happened by a number of "interested" parties carries, I think, a certain risk, the first of which among many, is hind-sight bias.

The Qantas incident reports says that faults also run in systems above this.

I'm wondering if the preflight planning or any discussions the crew had preflight might reveal the start of the chain that caused them to accept the flight plan.They must have studied the ITCZ wx and based their plans on that.

1. Would a flight plan rerouting direct to say west Africa then north be unavailable to 2 engine ops due to the long overwater leg ? Maybe not.

2. This leaves an alternate route to the north west of South America, with an enroute fuel stop which may have flightime limitations or even be impossible to reroute around the ITCZ considering its forecast size.

3. Have a go using radar to find a hole in the ITCZ. Maybe closer inspection will see if AF447 made any deviations. Nearest airways are along way away (UN866 and UB623). Crews turn off airways for a few miles without contacting ATC in a non radar environment. Especially allowing for the hassle of using HF radio when flying the aircraft is priority No.1.

4. If no luck in getting through then the possibility of dropping into Recife ( an AirFrance station in my days) for a replan.

SFD

ACARS
 

I'm not familiar with the FBW systems on any of the Airbus models, but hopefully someone can help me with this question. If the pilots were to manually shut down the flight computers (suspecting they were going haywire and compromising the safety of the a/c or to try to put the aircraft into Direct Law to contol it themselves), would ACARS send error messages stating that the computers had failed?

NotAnExpert;
No, the message sent would be that the computers had been turned OFF. ACARS reports of failure modes are almost always accompanied with text messages of the fault(s).

That said, there are no procedures in place for the crew to turn the flight computers, (PRIMs, SECs) off to "gain control of the airplane" - it doesn't work that way on any 320/330/340 type. The QF experience may or may not modify that.

Thank you PJ2
 

Thanks for your insight. I'm just trying to figure out how the computers could have failed in rapid succession, provided the unofficial reports of the ACARS messages are correct.

Those who talk/ask about re-routing at the flight-planning stage aren't fully aware of the operational realities of a longhaul operation.

If pilots were to ask dispatchers to route them around all the forecast areas of ISOL/OCNL CB activity that is in every SIGWX chart, there'd be absolute bedlam in every dispatch office. Some airlines even persist in choosing a route that takes you straight through an enroute cyclone/hurricane/typhoon.

It falls to the flight crew to assess the weather and order enough fuel to allow them to divert around individual/clumps of TS cells as they encounter them enroute; if your planned route takes you through an area of forecast ISOLated Cumulo nimBus, then you'd expect to uplift enough extra to go around one or two cells - not hugely inconvenient. But, however, if your flightplanned track looks like it will go through an area of OCcasioNaL CB, then it's time to think of taking a decent extra amount, in case the forecast is accurate and you wind up quite a way off track.

Some system failure or multiple failures of an extremely complex nature has befallen the crew on this occasion; I personally would very much doubt whether lightning had any contribution to play. My money is on probe icing or a dud ADIRU. The QF crew were fortunate enough to have been in day VMC for most of the event - which made their excellent handling of the failure that much easier. Night IMC would make it an entirely different proposition.

What were the tops?
 

I've seen tops above 60,000 ft at the equator. :uhoh: Accidental penetration of shorter columns can be violent. On the A310, you can loose both tat probes and loose Sat for a time with ice. This happened to us once going through a benign looking arm of weather a hundred miles from a typhoon near Borneo. The yaw dampers popped off followed by the autopilot. The Airbus autothrottles went bezerk so had to disconnect those. All airspeed was lost. It got very noisy from HAL screaming about wind shear and other incorrect imagined problems. All three Altimeters disagreed so we didn't know which was right. A few minutes later in clear wx everything came back. Like nothing happened!

My theory: I never had this happen in any boeing or douglas aircraft. I beleive airbus probe heating is occasionally weak (again, just compared to boeing.) I feel airbus automation actually increases pilot workload (AW&ST) Aug 1995, which is of course, exactly the opposite of how this equipment was originally marketed.

Composite tails are a concern also. FAA certification does not require full deflection capability in both directions I was told as was the case with AAL A300 in New York attributed to pilot error. Old Boeing iron however, has this capability: engineering far exceeding the minimum FAA certification specification. A few 747 era Boeings and DC-8's survived jet upsets that resulted in supersonic dives. I'm not sure todays composite airframes could do it? Are you?

These are just my opinions only. I never flew the A330.

Crunch - Out

I've seen a few suggestions that the weather radar may have failed. However, the crew is supposed to have sent an ACARS message saying they were flying through CB. Bearing in mind the flight was at night, doesn't that suggest that the weather radar must have been functional? Or could they have detected the CB visually even at night?

There is too much fixation on what exactly must have happened in this accident. Experience shows that it takes up to 5 contributing factors to end up in a fatal accident. One might be governing, but the others, if sequential or additional, contribute the rest to make it unsurvivable. Accidents like this one, with so little hard evidence up to now, and most probably for a very long time, are extremely hard to analyze in this respect.
Another thing we see is the debating of one single factor on a general, sometimes theoretical level. Sure enough every pro has his view of the things, but even he is basically a Monday morning quarterback, as the decision during the game is required on the spot, without handy close-up replay function. Any action or decision might be the third best option theoretically, but could be the best, worst or only one in real time.
The Swiss cheese model tells us that the holes might become lined up and that we must constantly try to mitigate this. The holes might look random from all our different angles, but they might have just aligned for the poor crew in question. Their angle of the circumstances is very difficult to duplicate.
Such factors/ holes would typically be: Crew training, crew experience, crew composition, sops, aircraft design. Subsequently flight planning, severe weather, fuel/load decisions, company pressure, fatigue and on top of that your bad day and simply bad luck.
There is the tendency to try to blame one or maybe two factors, but to actively forget the others.
It is a matter of perspective and interest. Keep that in mind.

The icing hypothesis
 

One hypothesis that has been raised in this forum is that severe icing might have had a role to play in a series of events in this disaster. How severe would airframe/pitot icing have to be to overwhelm the A330’s anti icing and de-icing systems? Are there any icing case studies on the A330 or other Airbus aircraft? What weight do the Airbus pilots on this forum give to this hypothesis?

I am hard pressed to find any reportable severe icing cases on medium to large commercial jets (of any type) in the last ten years (regional turbo props etc. being the exception).

Hello all,

Quote from bugg smasher:

I fly for Air France, and both these things are NOT available to us...

We do have SATCOM though, and regularly receive wx advisories from our Ops during flight, warning us of CAT, severe wx or other flight risks ahead of us.

There seems to be no doubt that the A/C entered a monstruous CB, but the only question, to which we probably will NEVER have a definitive answer is : How did they end up in there ?

ALL crewmembers were very thorough professionnals, one of the F/Os even had responsabilities as a "Pilot-on-watch" at our Operations center, and was extremely aware of the dangers of such flights (as were - no doubt - the other two, which I didn't know personnaly...).

As we all know, it's never just one thing... It's a sequence of events...

While PJ2 sleeps, may I inject yet another call on his behalf for some sanity on this thread?

We need more reliable info on the supposed 'ACARS' messages and MEL items for starters. Regarding 'catstrophic event' theorists, the info on the 'ACARS' messages we have indicates a slow but steady degredation of the systems over some 14 minutes (at least) with ACARS system power for all of that time.

I find it surpising that there has been no mention here of 123 (or even 121) chat regarding the ride and weather cells which I would have expected (and made myself) on that route. Do none of our posters have any info on actual route conditions at the time? Did any 'similar' traffic make significant route deviations?

I still think people are losing sight of the fact that when transiting the ITCZ, sometimes there is NO ideal way through. You've gotta punch your way somehow and that route depends on what looks better on the radar and outside.

But we don't, and may never, know what happened

Let's wait to see what the profesional crash investigators say, rather than rattle off all manner of tosh.