My only comment would be that the forecast is to be taken as a rough guide of only what to expect. It is far from accurate, and really only an indication of where there may be a few bumps and a bit of weather dodging. The scale of it, and the fact that it is only a forecast makes it of only little to moderate use.

RWA,

QANTAS group A330s (both -200 and -300) are equipped with Litton ADIRUs.

The other option available to customers is Honeywell.

So, can an Air France pilot/engineer tell us which ADIRU manufacturer they use?

I believe they only operate with high impact force (the manufacturer's notes don't mention water activation... only "crash situation"). I don't have any values for the g forces required, but I'd imagine they would need a respectable jolt to operate them (certainly higher than bumps sustained during aircraft ground handling). The sensor may be oriented in a particular plane/axis, so a mid-air breakup may not trigger it.

The ELT transmitter unit is mounted to the stringers on the upper fuselage and a short coaxial cable runs to the external antenna. The ELT has an internal battery pack.

Yes, there is a guarded switch on the cockpit overhead panel for both activating the ELT and cancelling a triggered ELT. You can't disable the unit with this switch, only reset it if it has been triggered. You may see this switch in cockpit photographs. The switch can either have a black plastic guard or a red/orange flap to keep it (the switch) in the armed position.

Rgds.
NSEU

Does a generator off line interuption cause the AP to disengage or change it's "law mode" in an Airbus? In the boeing it does and at an unopportune time ie flying into servere turbulance at night while on limited or load shedded power could increase the chances of inadvetant loss of control then A/C overload. A 737 was lost recently due to an unrecovered upset.

External sensors iced. => AP disengaged, alternate law with reduced securities, and so on.... (in a very disturbed environment, at night, over the sea, no visual references). Stall !

Thanks NSEU, it helps explain the lack of signal, I guess I expected even with an in-flight breakup that *some* sort of signal would have been receieved. (Not saying this is the case with AF, just generally speaking)

There's so many theories/hypothesis going around at the moment, but I did question one pilot stating in a blog that turbulence on its own could cause an accident... I thought that while one factor may contribute more than another, that it takes two or more factors (the holes in the cheese if you will) to result in something such as we have seen here...? So that would mean while turbulence may contribute to difficulty or damage there would have to be something else (system failure, human factor/control issues or stress) for it to result in a crash. Correct?

Where are prim1 and sec 1 located? Close to each other?

Unlikely but not to be ruled out:

http://www.dartmouth.edu/~chance/tea...es/Cassidy.pdf

A close shave, plane almost hit by "meteor" - Ajarn Forum - Living and Teaching In Thailand

The ELT used in our aircraft must sense a 5g force in any direction (spherical sensitivity) for a sustained duration of 11 milliseconds.

There are numerous flights leaving Brasil for Europe at this time of the evening. AF have a B744 flying GIG-GRU-CDG, not sure if this would take the same routing as an ETOPS twinjet though.

Other reports have mentioned a Lufthansa aircraft flying a similar northerly track from GRU-FRA that evening and not experiencing any sig wx problems.

I flew back on Saturday evening GIG-LHR on a BA B772, we experienced the usual light-moderate chop for a good few hours from the north east of Brasil, up over FLZ continuring 2hrs north of the Equator on a similar northbound routing. We took significant wx deviation just north of 0 deg before returning back to track.

Just a point. I'm a Boeing pilot and I'm not familiar with Airbus systems.

In the case of an electrical failure, there should be a systematic shut down of systems-ie non essential items first. Would ACARS fall into the bracket of a non essential item? Would the fact that it kept transmitting faults until a final catastrophic conclusion to the events(as indicated by the cabin v/s message) indicate a random shutdown of systems in a progressively deteriorating situation? Also there has been a suggestion that the on board mobile phone system continued to operate.

To me there is only one thing that could cause a shutdown that would leave non essential items operating while essential items such as the ADIRU's and ISIS shut down and that would be a fire in the avionics bay knocking out essential systems in an erratic manner and not shutting down non essientials first.

Whether the fire was caused by a lightning strike is another matter.

For the record I spent the evening yesterday with the family of a beautiful girl lost in this tragedy and am merely trying to better understand events.

Le Figaro (Paris) on the recovery mission.
 

"An Awacs radar aircraft is going to carry out a 'mapping' [cartographie] of the débris to try and determine the scene of the accident and thereby make possible the recovery of the black boxes. This mapping will be completed by a Falcon 50 which will take off from Natal, in Brazil, and by a fresh Atlantique 2 flight....

"The Pourquoi pas is en route to the area. Equipped with two robot submarines--a Nautilus mini-submarine and a research robot capable of operating in depths up to 6,000 metres--this Ifremer [French maritime research institute] vessel is eight days' sailing distance from the area. Its mission is to try to find and recover the Airbus' black boxes, whose signals will be transmitted for no more than thirty days. They can be recovered from depths of up to 4,000 metres in the Atlantic. 'A needle in a haystack,' as one expert summed it up on Tuesday. In the race against the clock to find these black boxes, the French military too has committed additional resources to the operation. Two Breguet Atlantic 2 'submarine-hunter' aircraft equipped with radar and long-range infrared scanners, as well as a Falcon 50 designed to detect pirates and drug-runners and an Awac radar aircraft will provide aerial coverage."

- I am reliably informed by a 330 man that the electrical system is different, so apparently yes. Personally I do not consider it 'irrelevant' however, as it shows what CAN be lost in an electric aeroplane and the problems that can ensue.

I don't think they are; I recall reading that they are in totally seperate bays.

It was an Air France PR guy that said it was a probable lightning strike. He just pulled it out of his A--. Nobody knows what happened. Hopefully they will recover the black boxes and get some real information.

normal to alternate law in bumps
 

In severe turbulence the AOA probes on the bus can be triggered into a disagree position which will trigger alternate law - removing many protections including the ability to stall the aircraft.

THe auto pilot will also disconnect at this point.

A reset of prims/secs etc may reengage normal law ( I think??? but not sure if it can only be done on the ground) .. then the AP becomes available again.

In big bumps it could always be possible to over control and overload the airframe if not careful.

Not saying any of this happened but if the ACARS was sending this type of report then might have occurred.

Will wait for the FDR but the airbus is certainly NOT uncrashable as AB would like us to believe..

W

Written by Red Paddy in post:


In the case of an electrical failure, there should be a systematic shut down of systems-ie non essential items first. Would ACARS fall into the bracket of a non essential item? Would the fact that it kept transmitting faults until a final catastrophic conclusion to the events(as indicated by the cabin v/s message) indicate a random shutdown of systems in a progressively deteriorating situation? Also there has been a suggestion that the on board mobile phone system continued to operate.

To me there is only one thing that could cause a shutdown that would leave non essential items operating while essential items such as the ADIRU's and ISIS shut down and that would be a fire in the avionics bay knocking out essential systems in an erratic manner and not shutting down non essientials first.

------------------------------

Exactly along the lines of what I have been thinking. On page 7 in this thread it is mentioned that ACARS is powered from AC1, and that it would be unpowered in an EMER ELEC CONFIG. That would indicate that the elctrics were working as long as the ACARS was transmitting, all the way until the vertical speed waring.

The flight controller computers are located away from eachother, so a single fire should not take out all of them.

So, if there is power, and at least some of the FCC's are working, what about the inputs (and outputs)? If all the sensors started to report conflicting information, how would that affect the computers? If there was not enouh consistant data to know what data to ignore.

No sir, that flight travelled though a tornado and experienced g loadings of +6.8g to -3.2g.

The most severe turbulence should not see more than 2g.

There is no suggestion that the AF 330 went into a tornado, at least not at the moment.

With the availability of modern satellite and data transmittion technology, the possibility of continual tx of FDR information should be possible. Given how essential that data is in understanding the causes of an accident perhaps this should be considered by the powers that be for A/C crossing deep oceans.

I know it would be costly, but then again so is the recovery of sunken black boxes.

The heavier pieces travelling further would though, be more likely to sink, no?

Thuis reducing the apparent surface debris field?

This looks like a good solution but there are issues in the details. One of these is that the satellite connection is easy to manage when the aircraft is flying in a normal attitude and with normal electrical power; it is not so easy in an emergency situation. You could end up with the remote recorder missing all the most interesting data because the connection was lost. Designing a system that will work in extreme conditions is much more demanding.

The problem is cost, of developing the system, and of transmitting that much data.

I've done some work on airborne satellite data and yes it is definitely very possible using existing services but it's not cheap. Take a big airline, and take how many planes they have airborne at any one time, and multiply this by the cost of (effectively) a DSL connection, and it will be well up in the millions a year.

Some satellite networks are struggling with reliability already. If you loaded up somebody like Immarsat with every jet sending a few hundred kbits/sec the whole lot would just collapse.

Then the data has to be collected from around the aircraft systems. Implementing a certified solution, across the many aircraft types, would be a huge task whose cost would make the satellite data cost pale into insignificance.

As the piece separated fall from a higher height, they are more affected by the air on their shape. This means they will land further away from each other, you would expect wings, back fuselage, forward to all end up in different areas and some to stay off to the side. Pieces would also come down with high air resistance on them to their weight, which would hold together more than a piece being aimed with low resistance and high kinetic force.

I would suggest that those looking for the crashed aircraft have a look at the Palomares B52 crash of 1966 when a nuclear weapon was lost in the Mediterranean for over two and a half months despite the full resources of the United States Navy looking for it.The bomb was located but was lost again when it was being recovered and it took a further two weeks to relocate it.
Recovering the recorders from the bottom of the ocean is going to be a very slow and difficult job,assuming that they are ever found.
1966 Palomares B-52 crash - Wikipedia, the free encyclopedia

New information provided by sources within Air France suggests, that the ACARS messages of system failures started to arrive at 02:10Z indicating, that the autopilot had disengaged and the fly by wire system had changed to alternate law. Between 02:11Z and 02:13Z a flurry of messages regarding ADIRU and ISIS faults arrived, at 02:13Z PRIM 1 and SEC 1 faults were indicated, at 02:14Z the last message received was an advisory regarding cabin vertical speed. That sequence of messages could not be independently verified.

Met synopsis
 

Tim Vasquez's report, whilst being fairly technical, concludes well. We don't at the moment know the ADD status of AF447 and what if any MEL's the a/c dispatched under. So called ETOP's dispatch with single radar, IRS fault or a prim/sec problem is not unfeasable. Comment was made that many crews frequently attempt to fly over weather; in an almost max weighted 330 or even 340, this would be folly. Pilots who have little experience of other types may attempt this manoeuvre but for those with L1011/747 classic/DC10 time, that would be a rare judgement call. The digi radar on the Bus requires more analysis and very carefull gain and tilt management than earlier analogue types. The buffet thresholds at close to or even at, max recommended or above optimum altitude levels are also narrower than non FBW types. For these reasons, lateral wx deviation, even by track displacements of over 100nm are not uncommon within the ICZ that I operate through. It appears through Tim's track analysis of 447, that no significant wx avoidance was applied. As an after thought, wrt CRM and crew rest issues, were the senior crew resting at the time of the 'event'? What was the crew pilot compliment/experience? was this a training sector for either the capt or F/O?
As a senior check and trainer on the 330 and 340, I always, without exception employ two cardinal rules.
. Rough air speed protocols versus altitude limitations must be applied early on in the piece. If the air is rough,(med/light, med turb and above), select M.78 without delay. "Chunking down" of mach to finally achieve target .78 is not recommended.
. Early wx deviation and crew lockdown is key to successfull wx damage avoidance. Never attempt to outclimb weather. Cherry picking the weaker cells and risking penetration of invisible gust regions, again is folly. Keep the big picture in mind, take the additional fuel at flight planning and large track mile deviations.
The above is intended to compliment Tim's fine piece and in no way wishes to undermine the severity of the event and its tragic outcome. RIP pax and fellow crew.

.

I suspect this a/c was broken up by a powerful Cb.

There are many precedents for this and the 'facts', such as they are, don't contradict this.

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.

I've had the misfortune to fly in a fully developed Cb- entirely my own fault I may as well add.

If I learned one thing about flying that day it's this:

Don't.

@LEVEL600
Ok, so the only "simple" explanation I could think of for a/p disengage + alt. law + 3 mins of ARIDU + ISIS fail messages would be a fault with pitot-static system (Aero Peru anyone? Not saying they were blocked on take off, but could've iced up).

PRIM/SEC 1 must've been still running off DC ESS and not HOT BAT as ACARS was TXing, correct? If it was a short on DC ESS that probably would take out more than just PRIM/SEC. I also presume that a lightning strike to a wing would've knocked some core censors out like fuel flow, etc, which would've been reported via ACARS?..

Just trying to fit theory to facts, not the other way around...

I do hope technology has evolved a little bit since 1966.

As for planning, unless my ETOPS alternates are below minima or there is a cyclone sitting on my flight track, the flight will depart. Any enroute WX affecting the flight will be briefed before departure and dealt with enroute. I think this is a pretty universal practice.

There seems to be some sort of consensus that this accident was in part caused by WX. AF 447 would not have left RIO without a working WX radar, given the enroute forecast. So if the WX was a factor (I'm not saying it was), why would they even go near it?

I have never flown through a CB in my entire career. I've been pretty close, in between, touched the edge, above, but never IN one. I've been 100 miles off track to avoid the monsters, in areas where only HF was available. There are contingency procedures for this scenario.

A failed Wx radar enroute would give the pilots some challenges. Continue, divert, return? They could have gone through WX already, so a turn back may have not be a good option. WX enroute to alternates could also be bad. So they would have found themselves between a rock and a hard place, trying to pick their way through CB's visually.

I don't have any statistics, but WX radars seem to have more failures than other systems. I had one fail on me just yesterday.

Pure speculations on my part, I really, really hope they find the cause of this one.

BTW, would a WX radar failure be an Acars event transmitted to maintenance?

Like all accidents, this it pretty hideous, and we can only hope to learn something before we move on.

I'm not an Airbus pilot, but I had a very major event in Boeing a while back, which involved multiple, and seemingly random and unrelated electrical failures. From the cockpit they made no sense, but a larger view showed that the wiring all ran through the same area.

BIG FAIL.

Go find the definition of severe and extreme turbulence then come back and retract this BS.

SLFinAZ:
I've been reading a lot and saying nothing, but this is pretty much where I've gotten to as well. My pure conjecture based on the alleged ACARS reports and timings, together with Tim Vasquez's excellent weather analysis: something very sudden and very violent (most likely although not necessarily: extraordinary turbulence) got the a/c badly out of shape, leading to deselection of autopilot and selection of "Alternate Law", and from then on who knows what caused the cascade of errors. Here's hoping they can get the FDR back at least.

Mindful of the fact that the a/c may have been in an abnormal situation, potentially in violent weather in the dark, I have one question (which hopefully is not too stupid) for those who can answer clearly. On this type, could electrical or computer failures relating to ADIRU and ISIS leave the pilots with no attitude or airspeed indication - or are there old-school hardware backup instruments on this type? As an add-on, if ADIRU and ISIS are completely non-functional, and you have no external horizon reference - is that even recoverable?

Just my stupid SLF question...

crew rest
 

"With 2 F/O's onboard what would the norm have been for crew resting, i.e. do AF use cruise Pilots, Commander at rest?"

Asked this very question of a 777 captain yesterday...at his carrier on a flight of this duration with 3 pilots there would be 3 blocks of rest...with the Captain taking the middle block. I asked about how long would that be into the flight and he said around 3-3.5 hours. I do not have any specific knowledge on what AF procedures are and if any of the 3 cockpit crewmembers were out of the cockpit during the incident. However, during our discussion it was felt that after exiting Brazilian Radar and going deep transoceanic that it 'could' be a 'possible' time for that rest.

Debris field size and extent
 

I suggest a look at the TWA 800 (B747 fuel tank explosion) report. Not because I suggest there is any similarity (there is yet no way for us to tell), but because it mentions (for the time) advanced software modeling to simulate the distribution of fragment trajectories based on their aerodynamic properties (size, weight, "lift/drag") to get an idea of the altitude at which parts separated and broke up.

With far more advanced computers and more accurate modeling these days, such an analysis of the debris distribution (taking into account known winds and currents) will be carried out and will, at the end of the day (... week, month, year, ...) give a very good idea of where and in what fashion the aircraft disintegrated.

Initial distribution of the bigger pieces will give a rough idea early on, whether it was an in-flight breakup, of destruction on impact.

Only time and meticulous investigation will tell.

As to the recorders: I can't believe the authorities have given up on recovering them. This is such a grave and rare event that it is essential to find out as accurately as possible what happened. Every effort will be made to recover those recorders, and perhaps even large parts of the airframe, depending on the findings from the recorder.


Bernd

Sorry guys but what does it matter about crew resting? The first and second officer together had more flying experience in the Airbus than the captain.

I wonder what effect positive lightning would have on the aircraft?

There is a gyroscopic horizon in the cockpit, if that's what you mean...

@FE Hoppy msg #673
 

Okay, maybe my way of writing wasn't correct. I meant severe weather associated with CB's or squall lines may cause turbulence beyond design limits of aircraft.

In general build up here in the netherlands is different from build up in the ITCZ (flew through it over africa, south america and the atlantic).
In my experience it is generally much less active here.
And normally we don't have many tornado's over here.

I am not saying this is what happened to the AF A330 as we just don't know what happened and probably won't know for months or even years if ever.
My point is only that CB's and associated phenomena may cause a break up.

A couple of questions / observations...

Firstly, the maps used on (for example the BBC) news sites seem to indicate a turn off the NE coast of Brazil, through a "gap" in the storm cells. Is this turn "real", or is it just a bad representation of a great circle route? Therefore did they actually fly through the system being mentioned? Or is the map just wrong?

Secondly, with regards to data transmission, surely we would only be looking at a couple of kb for position information, rather than tens or hundreds? Also, would it really matter about its ability to transmit / receive at every attitude / aircraft state? Surely the fact it can give a "last known position" is still better than what we have here?

As for an EPIRB or something similar, wouldn't you just put something (perhaps in the top of the tail) that would be barostatically activated (I would say on contact with water, but then there is such a thing as rain) and detach from the aircraft, float, and start transmitting?

I imagine that he means if it was inflated that would mean that there is a slight possibility the pax and crew or some of them or one of thembmanaged to get out of the plane when in the water. Personally don't think there would be a chance at all but I imagine that they were refering to that.

Very sad event and my heart goes out to those affected by this in anyway.


ABC