Hi,

My understanding of the BEA note is they are not accurate ....
When you make the sum of speed invalid time it's more than "less than one minute"
It's two losses of speed indication
Was better to put also a foot note for the second loss of valid speed.
It's important for the case.

No because the notes where in chronological order. They put that note after the first loss of indication. Which is where it belonged.

BTW can you tell me where you got this quote you posted?

I ask because google has never heard of that quote.... and gogole knows everything. ;)

I stand by post#1 here, posted nearly two years ago, and would repeat another post somewhere else that an easily accessible big button on this type of system is needed to enable direct control (assuming, of course, we have pilots in the cockpit and not computer operators:mad:).

There is still, even after all these years and accidents, much yet to be discovered on this FBW system and its failure/reversionary modes which appear to be built on the assumption that 'nothing can really go wrong so we don't need to worry too much about it.' Murphy's law applies.

beinville
you say I should google it?
jesus is that where you get your knowledge from?

Fact from personal experience .

All of my stall warnings in airliners have occurred in approach configuration low down in turbulence except for one in a high level holding pattern which was a mach stall.

Besides the obvious factors the margin over the stall is at it's minimum.

Once in initial climb at MTOW we hit minus 20+knots windshear with T/O thrust - procedure was full thrust and +5 pitch or thereabouts.
Speed was below V2.
Skipper followed procedure but speed decreased - he ignored my calls so I got on the stick and gently pushed it to drop the nose a couple of degrees and we started accelerating.(lower drag).

You have to realize that today everyone is taught to follow SOP but they do not always work.

The pilots did NOT fight the trim.
Please read the Report!
They produced/aggravated the trim.
Had they pushed the stick forward the NU trim would have been reduced by the Auto- trim.
There is NO indication of a runaway trim. It seems it was a commanded trim.

No I'm asking you why you say I am wrong?

The plane stalled at ~37,000 feet. There was absolutely no reason the pilot had to 'grab sky". Quite the contrary he was too high and (most surly) would not have stalled at 15,000 feet.

Now if you can tell me how I'm wrong, I'm all ears.

AND BTW your training or the lack thereof has nothing to do with this flight.

As I read BEA I was puzzled by THS being in almost full up position for about 3,5 minutes and not changing its position although PF made pitch-down input. Unfortunately report doesn't mention for how long pitch-down input lasted. I took my copy of A330 FCOM (not current one) and found out, please correct if I am wrong, that flight control law could have changed from ALT 2 to Abnormal attitude as angle of attack was greater than 30 deg causing no auto trim available until angle of attack decreases below 30 deg, which according to BEA report did not happen.

https://lh4.googleusercontent.com/-w...011_095849.jpg

Is there any indication in the cockpit when this happens?

Stall recovery and auto flight
 

All

We have a loss of airspeed data because of ice in the pito that lasted for under a minute.

This triggered Alternate Law

After this the pitos came back, with the aircraft in a deep stall

Some questions :

1. Could the auto flight system be re-engaged in the stall ?

2. If so , would Alpha floor pulled them out of the stall ?


Simon

BEA Report – The trimmable horizontal stabilizer (THS) passed from 3 to 13 degrees nose-up in about 1 minute and remained in the latter position until the end of the flight.

The last recorded values were a pitch attitude of 16.2 degrees nose-up, a roll angle of 5.3 degrees left and a vertical speed of -10,912 ft/min.

Where is the BEA quoted (THS) trim nose-up angle measured?

Is it an internal computed value displayed on EICAS?

Is it 13.2º on the cockpit pedestal trim wheels?

Is it 13.2º as shown on some aircraft where the horizontal stabiliser (tailplane) leading edge fairing meets the vertical fin?

Or ..... ?

It seems the problem is even the best pilots don't totally understand everything about their aircraft! It seems you need to do an IT course not a flight training course for this plane! Then you have the problem of airbus themselves claiming it couldnt stall!How many incidents have occurrd with the computer workIng against the pilots!

Frankly it's like a horror si-Fi movie of robots that try take over the world, the machine thinks it's better then the pilots, and the makers don't understand the complicated rare events, the events that kill.:oh:

Hi,

Seem's Google is no more reliable .. lol
http://henrimarnetcornus.20minutes-b...1718484589.pdf

I'm not sure how this nonsense got started... the computer was not "working against the pilot"... The report today CLEARLY says that all engine controls and input controls were functioning perfectly.

The pilots were working against common sense. When a plane stalls you push the nose down, not up. End of discussion.

> Seem's Google is no more reliable .. lol

OK anything more reliable than some guy's blog who today posted a quote that nobody has ever seen before?

Hmmm, looking through all the ACARS and the information we have at the moment I surely must have overseen the part where it was stated that all PRIM's were deactivated. I have seen PRIM1 and SEC1 but nothing more.
Could you point me to the information indicating loss of all PRIM's ?
That would have led to Direct Law btw.
Also I'm missing the part where it was stated that the pilots were vigorously commanding Nose Down only to be overriden by the Trim ?

henra one thing I really learned tonight is that people just make stuff up.

Beinville
you have to step back and put your thinking hat on.

One of the most frightening and unique generated sounds in a cockpit is the death rattle.

Add the fear, fatigue, disorientation and hypoxia factors to a host of contradictory information then the brain prioritizes.

The crew were faced with false stall warnings, overspeed warnings, control law warning, turbulence, probable dutch roll and a stab that was moving to the aft limit for whatever b****y reason.

I very much doubt if anyone in the crew had ever flown manually at altitude.

The body tenses with stress and fear and primeval instinct is to wrap oneself up in the foetal position - which could have resulted in the PF inadvertently putting a nose up input on the stick while he was sorting out the roll and what was really happening.

They had very little time and whether or not they had any correct speed indications they did not have the time to diagnose what was right or wrong.

Remember the air india 747 which rolled on it's back with a faulty horizon after take off - one instrument failure only.

BA nearly lost a 747 - the LAX one- as the crew didn't understand the basics of the fuel system and that technology goes back to Noah.
They also had the whole night to play around with it and get it wrong.

The myriad of posts trying to fathom out the computer system shows that it is not understood by the average bloke.

From yesterday's note from the BEA ... apart from the stall warning ... indeed there seems to be no indication (from the CVR) that they realized they were into a stall? If there was, why would the BEA chose to leave it out of their note?

That kind of analysis is the last thing I would expect to see in an accident report.

The crew deserves a more thorough analysis

I think Blind Pew needs to follow his own advice and step back...

Ten out of ten for drama, five out of ten for accuracy. False stall and overspeed warnings are to be expected wth unreliable IAS. Control law warning - no big deal, alternate law is benign. Turbulence? An assumption. Dutch roll? And assumption. Moving stab? Not an issue. It was functioning as designed and the crew would not likely even be aware of the stab position.

I have flown an Airbus manually at altitude. It's exactly the same as flying it at 10,000 feet thanks to the flight control laws, either in Normal or Alternate law. It's not an issue.

Errrrr - you don't accidentally put full back stick on, and not for 30 secs. Your arm will get very tired.

Thats why you have an unreliable airspeed recall item.

There was never any chance of losing the aircraft, and the issue which manifested itself only became apparent at top of descent and would have resolved itself of it's own accord anyway. Lots of fuss about nothing.

Fortunately 'average blokes' aren't let loose on multi-million dollar airliners. They have to have a lot of training first, which is why many Airbus experienced pilots find this kind of speculation tedious.:ugh:

blind pew

No evidence so far released to consider hypoxia as a factor.

I wonder what the investigation will find, why the PF refrained from simply attitude flying. All attidude indicators should have been functional all the time and are the only hope to survive hand flying at night over ocean with partial panel. With the turbulence, roll and falling sensations vertigo had definitely set in. You can't fly by the pants over the ocean at night in a thunderstorm. The pilots had a mostly blue attidude indicatior in front of them, with ROD unwinding like hell. With all electrics operational inertial systems are very reliable. Can one of the Bus drivers comment if the flight display shows the attitude indicator in the situation they where in and not some garbage error messages?

Was the first stall warning valid?
 

How did they gain 3000 feet at a rate of 7000 feet/minute if they started off in a stall? Is it possible they were trying to climb over the weather? Or that they were in a strong updraft?

jcjeant
Read the BEA document again: it doesn't say that invalid speed condition lasted less than one minute, it says that inconsistency between LH speed display and ISIS speed display lasted less than one minute.
(my bold)

We can probably infer that further invalid speed conditions were equally reported on LH panel and on ISIS.

Aussie
guess you have never had a whiff of oxygen in cruise at night and seen what effect it has on the eyes.

others
BA 747 - why did they declare a mayday into egcc if they new what they were doing.

Didn't say they put full back pressure on the stick for 30 secs but I have witnessed pilots unintentional inputs when stressed.

Often in sailplanes had guys push right rudder or both when they thought they were not going to stop.

Never witnessed a anyone take the autopilot out in cruise at night to hand fly it - but then again I only worked for three flag carriers.

But then again we had SOPs which said we weren't allowed to fly manual if CWS was available - same with A/T on several types.

We can also probably infer that the crew, having had fluctuating and differing airspeed indications, did not trust anything they saw on any ASI by the end, even if they had settled down.

G

Could anybody tell me why on a airliner that should have at least 3 sources of speed indicator (pitot tubes, GPS and inertial system), why the crew did not rely on the 2 sources that have been concomitant : GPS or inertial ?

As a pilot you know you are going to die at night over the ocean in a thunderstrom if you trust no instrument at all. I expect more will to survive from any pilot.

blind pew

No,I only see it during the day in my operating theaters. So what kind of oxygen saturation then are you pilots registering then, in cruise. Why do your companies think this appropriate to normal flying. Why would pilots not insist on some oxygen supplementation normally, or don masks during such an abnormal circumstance.

Genghis
Sure. So we are back to my very first question: before discussing how they could have detected/fixed the stall condition, I'd like to understand why they didn't apply the unreliable airspeed procedure (fly pitch/thrust) in the very first place, which would probably have prevented the stall condition from developing.

As I read it from the few comments of 'bus drivers here, this seems to be the initial human cause of the issue (just after the technical cause associated with pitots malfunction).

Hi,

Well .. it's come already over 300 posts !
And it's all speculations ... like any speculations .. or debuncking made after leaks in the press
I think I can name the BEA communication as "an official leak"
Just like in the newspapers (fragmented information who can only lead to more speculations) but this time the newspaper name is "BEA Time"

That does seem to me to be the single biggest question - these chaps were experienced and current pilots unlikely to make such an elementary error. It seems likely that there is some other factor that we just can't see in the evidence at the moment.

G

Pitots
 

Three identical pitot tubes icing up uniformly and finally and collectively failing to provide AS information was the route cause of this accident.

Had they been manufactured by different companies they might have had a differential failure rate.

Just a thought.

What could have bee arrived if the crew would have forgottent to rely on the pitot and would have tried to sustain 400kts ground speed below FL300 using GPS or inertial ?

Please answer.

@ Blind Pew - Re the BA747 - just because they declared a mayday doesn't mean there was an actual threat to the aircraft present. The circumstances of the incident are now public knowledge. The aircraft was safely flyable with sufficient fuel at all times. There was no danger present, although the incorrect suspicion that there might be led to an abundance of over-caution.

On the subject of the back-stick input, it's well known that people can thrash the controls under extreme stress without realising it. However to maintain that input for a prolonged period is concerning.

Few people will disconnect an autopilot at cruise levels for a jolly, but most of us will have been required to do so at one time or another. The A320 is a far easier aircraft to fly at altitude than a 747 as it exhibits the same behaviour throughout the envelope. I presume the A330 is the same.

The speeds were invalid because of disagreements between the sources ("incohérence") from 2:10:05 to 2:10:51, which is indeed a little less than one minute.

They then became invalid again at 2:11:40 until 2:12:02+15 -- but, as the report pointedly states, because of IAS falling below 60KT, NOT because of disagreement between the sources.

Aussie
we fly at cabin altitude of 8000ft.
the partial pressure of O2 is further decreased by recirculating the air through the cabin.
On long high flights it can result in severe headaches amongst other symptoms.
Anything over eight hours I developed bad ones.
Age paid it's price as well.
Many of our guys used our masks for 10 mins before we started descent on long haul night flights as well as when we were tired on short haul or hung over.
I've also used O2 around the ITCZ.
Once erroneously deviated 100+miles off track (with permission) due to miss reading the wx radar. Putting on the mask helped me to literally see the picture.

The air /O2 quality issue has somewhat been addressed by the dreamliner and O2 scrubbers.

But it goes back to cost and recirculation fans burn less kerosene than bleed air consumption.

hand solo
I know there wasn't any threat to the 747 but the crew didn't.
They declared what they thought was a genuine mayday and that there was a serious fault with the fuel system.
The cross feed procedure had been changed by BA to use the jettison pumps.
Although the manuals were correct none of the crew understood the basics of jettison pump feed.
The incident resulted in a change of checklist procedures as well as training.
It's all in the report.

This was a simple system not rocket science.

And the three of them had hours to refresh their knowledge as well as totally valid information.

Don't forget that our american cousins were seriously p*****d off with this fiasco.

My point is the air france boys had the cards stacked against themselves and I sincerely believe with the little that we know so far that it was an accident waiting to happen and but for allah I would end up in the same boat.

I was also puzzled about this fact. On the one hand the text says A/THR failure.
I am not sure if this is the same as A/THR disconnect or if it strictly means failure.
On the other hand there seems to be no indication of Alpha_floor activation. But this could also be due to ADR disagree.

Somehow, I feel that there is much discussion about the safety of the FBW-systems but not from control theory point of view. From control theory point of view the functionality is more important that the means the functionality is implemented. The same functionality can often be implemented with computers or analog devices. As far as I have understand, computers are often more reliable.

With computers you can implement features that can not be implemented with analog devices. However, the basic questions remains the same. You have to solve at least stability, reliability, controlability and observability problems.


I have a feeling that that the pilot aids are not the core problem but the practices. I don't know if the sales men, who promote the new protections, or technical persons who don't reorganize the potential problems, should be blamed.


When you have deep enough understanding on the control theory, you should understand that every time a inequality constraint is changing the status, the risk level is increased. When there are too many inequality constraints in the system, it becomes practically impossible to analyze it completely.


The common sense says that when system is driven against too many constraints, the control system capabilities are misused. It corresponds the reasons of the financial crisis: “insure” instruments were used as money making instruments.


I feel that every time a control law is driven against “hard” protection constraints, someone has made, at leas a small, mistake in the chain form design to practice. If it is a common practice to solve problems by driven the system against protections, there is something fundamental wrong in the culture.


I feel that every time protection is activated the situation should be studied afterward and practice to avoid the activation of protection should be learned. If it is acceptable to use protections in a normal operation, the safety gains of the protections are destroyed. Most likely the safety is decreased because the skills of the pilot are not gained.


As far as I have understood right, the cause of this accident is pilot error. It is hard to deny it. The real question is: what lead to the errors. We might found out that they acted relatively reasonable...


As a control engineer I feel that would be relatively easy to substitute the pilot in the “normal” conditions. I feel that the pilots are in on board to solve unexpected situations. Humans are better than computers in those conditions. However, human has to learn how to act. If in the training everything goes too smoothly, I have to ask what in hell the pilots do in the cockpit? The problem solvers have to trained to solve problems.