PNF.

PNF said "so, we’ve lost the speeds" then "alternate law [...]".

The airplane began to roll to the right and the PF made a left nose-up input.

initial input: left nose-up
response: The airplane’s pitch attitude increased progressively beyond 10 degrees and the plane started to climb.
result: vertical speed, (which) had reached 7,000 ft/min

From 2 h 10 min 05 (4), the autopilot then auto-thrust disengaged and the PF said "I have the controls".

As I read it, PF taking control was a response to AP/ATHR disconnect.

PNF's assessment seems to corroborate the evidence that AP disconnect is linked to loss of airspeed: PNF said "so, we’ve lost the speeds" then "alternate law [...]".

From 2 h 10 min 05(4), the autopilot then auto-thrust disengaged and the PF said "I have the controls". The airplane began to roll to the right and the PF made a left nose-up input. The stall warning sounded twice in a row. The recorded parameters show a sharp fall from about 275 kt to 60 kt in the speed displayed on the left primary flight display (PFD), then a few moments later in the speed displayed on the integrated standby instrument system (ISIS).
Note 1: Only the speeds displayed on the left PFD and the ISIS are recorded on the FDR; the speed displayed on the right side is not recorded.
Note 2: Autopilot and auto-thrust remained disengaged for the rest of the flight. At 2 h 10 min 16, the PNF said "so, we’ve lost the speeds" then "alternate law [...]".

The crew seem to agree with your assessment. Their actions and comments seem to ignore the first stall warning here.

Note 2 : In alternate or direct law, the angle-of-attack protections are no longer available but a stall warning is triggered when the greatest of the valid angle-of-attack values exceeds a certain threshold.

Does this mean in Normal Law stall warning is coming from airspeed?

You don't seriously think that what's in the BEA note is all of the communication in the cockpit, do you?

JDEE - When PF initialy reduced the VS from 7000 to 700 the aircraft had not actualy stalled. The first stall warnings were false due to the eroneous speed indications. These also led to the AP and ATHR disconects and the reversion to alternate law. Therefore his actions to reduce the climb were partialy sucessfull. If you mean his actions did not unstall the aircraft as I said they were not stalled at this point.

Later on the PF made pitch down movements which resulted in reduced AoA and increased speed - therefore the situation was recoverable.

Cog sim - the computer had nothing to do with maintaining the stall as PF was able to reduce pitch when he chose so to do.

Would anyone care to comment on how many times during their career they have experienced an uncomanded reversion to alt law?

What is the stall speed at FL380, 350, 300, 200, 100 sea level?

Some one mentioned earlier the colgan crash and I have to agree there are similarities in that in both cases the PF would apear to have reacted incorectly to impending and actual stall. - No one plans to stall for real, accidental stalls ocur when we least expect them and are probably most unprepared for them. In order to survive quick recognition of the situation followed by apropriate response.
This in turn derives from the training - if this is inadequate or inapropriate then the wrong responses follow.

This means in normal law AoA protection is active (which should prevent a stall in the first place).

I think myself and theav8tr are thinking along the same lines. When it's a long flight, boredom in the cockpit and one overriding thing is there to focus the mind, in this instance the oncoming weather, all the mental ideas you have go into solving that problem.

I think the initial loss of A/P and A/T weren't the problem but a mental desire to get out of the icing layer/weather and certainly to not descend and enter even worse bad weather. Hence the initial response to climb and I believe initial pull-up actions.

Any later pilot responses to a stall warning that may have followed is another matter but I think that is one possible explanation of the primary actions taken by the crew i.e. nose -up input, and is being mistaken here as an incorrect response to the stall.

in this statement computer = auto-trim and stall warning disappearing/reappearing below/above 60kt threshold.

What I perhaps should have said is the "computer" as defined above, was making it gradually more difficult for the crew to get out of it.

:cool:No that's the normal overspeed Protection but Nobody on this thread is speaking about the proper reaction in case of unreliAble airspeed : pitch and power ( about 2.5 degrees pitch and 85/100 n1) and then switch out the faulty ADR . And surely not climbing 3000 ft at Max FL , trying to stop the airspeed( the faulty one ) from accelerating

"CogSim, good catch on the PF never acknowledging the PNF statements"

With only fifteen snippets of conversation released by BEA from about the last twenty minutes of recordings, maybe it is bit premature to accept that as fact

JD-EE and CogSim,

At this stage I wouldn't put much weight on what we know of crew interactions (i.e. one crew member acknowledging or not acknowledging another's words). The words of the crew released by BEA would have been selected to provide some context (not all by any means) to assist us (the public) in understanding the most basic aspects of what happened. The how's and why's are still a long way off.

In the last 10 mins of the flight -- especially the last four -- we can be certain there was a great deal of crew interaction.

Thank you. At least the PNF was showing enough awareness to respect the stall warning.

More questions raised by the BEA report, probably impossible to answer with certainty I'm afraid

1. Would the speed reduction from M0.82 to M0.80 have been completed between 2:08 and 2:10? - if not the engine speed on auto-thrust disconnect could be below that needed for maintaining steady flight. Rudder limit consistent with FL350 and M0.80, but 'about 275 kt' a little high?

2. Is it correct to assume captain would have been PNF in the left-hand seat at T/O, so the PF was in the right-hand seat - and speeds shown on right-hand-side are not recorded?

3. Am I right in thinking that the ISIS displays the air speed from the 3rd pitot? Indicated speed falling low on both left PFD and the ISIS could then be caused by pitot ram ports blocking with drain clear - leaving possibility that the right PFD has frozen ram and drain and will indicate increasing speed with increasing altitude?

4. In the A340 airprox incident an "alpha floor" protection increased engine speed to max even when autothrust disengaged - could this have happened here, possibly at time of first stall warning.

promani
The reported conversation is "minimal" and IMO only to support the flight control inputs and disclosed aircraft response so far released.

There is much unexplained data dealing with PRIMS/SECS (per ACARS) that may lead to different explanations at a later date.

MM43 quote: I notice a number of regular posters are quiet, which is to be expected

I have purposefully remained silent after reading the BEA report, which is very short on detail, and which unfortunately goes along with what I expected. The French are very careful to paint any picture which might point a finger at National interests. Now, don’t take this as conspiracy related, just factual based on previous investigations. To date, they have only thrown us a bone, factually and judicially correct, but still lacking the meat which completes the actions of airplane and crew that suffered the results. What transpired during the deafening voids in the explanation sing out louder that then statement. More to come I sincerely hope. For those of us who made our living in their seats, and for those still sitting there, can probably build a defendable position on what happen, and why. We can now only hope that the evidence released and reported will be true, and will thereby accelerate the needed corrections. Until then, I fear the airplane will fly under a cloud of doubt, rather than on top where it rightfully belongs.

Hi bear,
I do seem to remember that you had posted a very clear question.
I simply tried to answer it.
If you do think that "30 seconds of full back deflection" is not "continuous back stick", what is it?
Read yourself. You didn't ask for an explanation, but doubted that it was even written in this report.
Barking with dogs after those AF pilots is not in my mentality as I'm also looking for some reasons explaining those unfortunate PF imputs.
My perspective is different than yours as I'm looking for other factors. I would like to know how many trainings this pilot ever did involving a high altitude stall without any protection vs. recovering from a low altitude stall with full flight envelope protection. I guess he did a lot of the later but maybe, never practiced the former.
The danger is obvious as both case could use opposite imputs and a pilot only trained to one form may have reacted instinctively by the opposite move. Full back stick deflection would give Alpha_floor/Alpha_Max in one case and a full stall on the other case. All it would need is a pilot unaware that the protections won't kick in (ie. Perpignan).

[quote]GY, maybe this answers some questions?

Quote:
At 2 h 10 min 16, the PNF said "so, we’ve lost the speeds" then "alternate law […]". Note 1: The angle of attack is the angle between the airflow and longitudinal axis of the airplane. This information is not presented to pilots.

Note 2 : In alternate or direct law, the angle-of-attack protections are no longer available but a stall warning is triggered when the greatest of the valid angle-of-attack values exceeds a certain threshold.

The airplane’s pitch attitude increased progressively beyond 10 degrees and the plane started to climb. The PF made nose-down control inputs and alternately left and right roll inputs. The vertical speed, which had reached 7,000 ft/min, dropped to 700 ft/min and the roll varied between 12 degrees right and 10 degrees left. The speed displayed on the left side increased sharply to 215 kt (Mach 0.68). The airplane was then at an altitude of about 37,500 ft and the recorded angle of attack was around 4 degrees
This is the important part: "The PF made nose-down control inputs and alternately left and right roll inputs."

The PF did indeed stick the nose down. It didn't work.

This is what caused the climb:

Irrespective of the stall warning that followed the aircraft was ALREADY in the climb that appears to have sealed it's fate. Remember STALL is a function of AoA (are you sure you understand this?).

The pitch-down stick down movements were effective, and may have saved the aircraft if continued however for some reason they were not and airspeed at this time was (presumably) bleeding off due to AoA.

Anyway it's a shame, because I'm loosing respect for some posters here since some fairly basic data points are being glossed over to make some other story match the end result.

No mention of the PICs negligence in leaving the flight deck prior to entering an area of severe CB activity. He had to have known that there was severe CBs in the area was there from his briefing and from listening to other aircraft deviating. Any flight over the ICTZ has a great chance of experiencing monstous CBs!
The fact that the relief pilot and the SIC made attempts to call him back to the flight deck signifies that they were overwhelmed with what they faced.
In hindsight, a 200+ mile deviation left or right of the CBs that night would have saved all the lives on that plane. As to why they didn't do this is anyone's guess.

mm43

Yes I agree with you there 100%. After 2 years BEA only gives a little information, that I think to myself that they are playing games. Just teasing us. But I know that is not true. Just the way they do things.
Pity the US was not investigating this accident. Then all would be revealed, or at least most, whether or not the judiciary was involved. Oh well 2 months to go....

After the accident I went through stall, UAS, training in the sim, as per Airbus syllabus.

I was kindly allowed an extra exercise at FL350, about 170 tons, CG around 30%, about one year ago. Pull up from FL350, all 3 ADRs off, kept it at 15 degrees up till it stalled, à la B707/27/37, A310, in gone years.

THS went full back, don’t remember the figure, and sidestick was released, N1 at 85% (A/THR off). The nose came down to about -5 and went back up to +10. Rate of descent was between about 6K fpm and zero, or slight climb (sim is an A330 with PW engines, 85% is slightly above needed N1 for turbulence at M 0.80).

Recovery was done by pushing forward. The surprise, for me, was not the amount of force on the stick to keep that nose about 3 degrees down, in order to get the THS in a comfortable position, about 3 up, at, oops, about 20000’. The surprise was how so long it took. The flight controls never went from ALT to Direct Law.

Shame, I did not try it with full THS up and full forward stick in Direct Law.

Someone posted, my thanks, that stall training is done with stab trim not behind normal (scheduled) IAS for the configuration. That happened to me, even in the military. No problem at the time, no A/P, no autotrim. Problem later, with “moving stabilizer” stall, with A/P ON (B707, 727,737, A310). Same with autotrim aircraft, A320/330, if not properly handled. Check out the OEB concerning Radio Altimeter wrong reading to zero, versus stabilizer trim during go around, as well.

Let’s wait for a more complete report, CVR and flight data.

BananaAir

"He had to have known that there was severe CBs in the area was there from his briefing and from listening to other aircraft deviating."

How do you know what he knew? Are you aware of the flight crew's experience on that sector, and the rotations performed? What the captain knew and what he should have known, may be two different things.

@wes_wall : The BEA these days is a very different organisation than it was in 1988. I think it's only fair that we give them a chance to get to grips with the data and release information as they see fit.

Basic questions/thoughts (please correct! - non-pilot asking)
 

1. I think AoA sensors are different from speed sensors, but could the pilots have believed that both were invalid?

2. I would like to know how this sequence of events was particularly affected by this being an Airbus - couldn't any make of airliner not suffer defective speed sensors, and the crew not have to control the plane in the dark using a basic understanding of the altitude/ attitude and AoA?

3. If the pilots did believe the stall warning, their AoA increase was so much that the stall warning went away, which they may have interpreted as success. However should it not have rung alarm bells that this was the result of nose-up inputs? What would the artificial horizon have been showing?

4. In the later stages, it appears they attributed their altitude loss to being in an unstalled dive, and only at a much lower altitude did they push-down, perhaps confusingly turning-on the stall signal (still deep in stall), and by then there was too much altitude loss to recover steady flight? Did the pilots ever notice that their speed signals were in alignment? And wouldn't their slow speed have been an indicator that they were not in a dive?

BananaAir

I agree with promani re your jumping to conclusions. At this stage, your use of the word "negligence" to refer to the Catapin's actions is most unfair and irresponsible.


Promani

Your reference to wishing the USA was conducting this investigation sounds somewhat parochial. In my experience, Dozy is correct re his comment above that the BEA is an entirely different organisation than it was a few years ago. (A fact that is also true, BTW, of many other countries' avation investigative boards.)

I've flown through that zone and it should be manageable on a normal night without needing the captain to be in the cockpit if it is his rest time. We are normally deviating around weather. They both seemed happy with the 12 degree left deviation. A bit of turbulence is normal in that situation so the FO advised the FA's. Somehow the pitot tube icing up caused the pilot flying who hadn't probably handflown the airplane much before lost his airspeed thought Airbus says it won't stall so pulled back so when the static source at his higher altitude gave him with the trapped pitot pressure caused the overspeed warning he retarded the throttle, then came the stall warning which he ignored so put it in a deep stall 3,000 ft above his assigned altitude. You cannot zoom climb an airplane that large without running out of airspeed. Everybody knows that. Other than monitoring the autopilot I wonder how many hours he had flying manually in an airliner. I heard he had 800 hrs in type and less than 3,000 total hours. How many hours was not monitoring the autopilot?

This new generation of low time pilots might not cost much pay wise but what do you think Air France paid for this crash?

techgeek said
That misses the point completely. I know there are great people writing software - the problem is not with the people, it's with the methodology, or philosophy, or whatever you want to call it. The problems are bent around the idioms, instead of creating or using natural idioms based on the problem. It doesn't matter how good you are, you end up making reality bend to the design document, only it won't bend in the end.

I think it was bratschewurst who suggested there may well have been no need for any (substantial) pilot stick input at first knockings.

That I can get behind, possibly one of the better observations here

Another might be that if the Captain upon entering the cockpit could have seen immediately a very obvious AoA and a very obvious stick position, perhaps this thread wouldn't exist...

..which leads also to the thought that he surely must have noticed the deck angle upon his return ot the cockpit, if only by energy exerted per yard of progress ?

If so, then did he realise what the PF was doing, indeed is there any CPN and PF dialogue along those lines?

Tom Laxey, in relation to your first question if my memory serves way back on the first thread it was revealed this particular A330-200 did not have AOA sensors mounted. That should be checked as it has tremendous bearing on some of our bloviating here.

(And I did say "our", guys.)

syseng68k

The autopilot drops out involuntarily for other than UAS ADIRU disagree.
The input limits have been posted before, so subject to correction, I believe they are 45 degrees roll, 13 degrees Nose up, and 9 degrees nose down. for reasons other than max deflection, there are trend issues and off phase limiting? When the auto pilot is overwhelmed, the pilots get the a/c back in non degraded Law, Normal, ALTERNATE LAW is self selected if the cause is ADIRU disagree. Again, this is subject to a type guy.

You are precisely on point, for from the moment of A/P drop the pilots know they are in command subject to the Law selected, and they must be 'au courant' instantly. Without putting too fine a point on things, "I have the controls" is a professional and expected thing to say by the PF. He said this, and made a correction just after a/p had dropped, so an out of trim condition is not cause for concern.

I have a bit of a problem understanding why others don't see this handover as the "beginning" of things going rapidly pear.

detailed meteorological analysis from the time
 

Newbie here, not a pilot, but I've been following this since it happened and here is a link to a detailed meteorological analysis posted at the time, so none of the current information being discussed was known then.

I'm not posting this because of their attempts to understand what happened with the limited knowledge at the time, rather because of the extensive weather information and analysis given at the time. I wonder from the pilots here, if any of this analysis might explain the mystery of the continued nose up.

Air France 447 - AFR447 - A detailed meteorological analysis - Satellite and weather data

AoA sensor or AoA INSTRUMENT/DISPLAY?????

How does the plane figure a stall without AoA sensors? Or compute AoA protection in Normal Law?

Answers on a post card....

There are Three Angle Of Attack (AOA) sensors, one on left (#1),
two on right (#2, #3) of airplane nose...

Did Airbus have a idea what happen to AF447 a year and a half ago?

www.flightglobal.com/articles/2009/09/09/331991/aa09-pilot-handling-skills-under-threat-says-airbus.html

Garage Years

Quote:
"...From 2 h 10 min 05, the autopilot then auto-thrust disengaged and the PF said "I have the controls". The airplane began to roll to the right and the PF made a left nose-up input...."

:ok:

Things don't CENTER for the pilot when he gets it back from Otto. Something made the slave go poof, and why does it have to be UAS? It may well have been. His first inputs seem to be an adjustment for something the ap had trimmed out. It doesn't look like Pitch and Power to me. It looks like "give me a lower speed and some energy when I arrive at the top." Overspeed in still air is a bad thing, in turbulence it is to die for. Power is Altitude, Attitude is airspeed. PF was transacting business, who on God's Earth has enough data to question him at this point? OR believe me? Sherlock is rolling his eyes mon freres.

Does anyone have a clue about what these gents were (may have been) IN?

Anyone ever hear a Stall chirp at speed?

Couldn't find neither "overspeed warning" nor "retarded the throttle" at this stage in the report. Wouldn't at least an overspeed warning have been mentioned?

Also, the PF didn't ignore subsequent stall warning: "The thrust levers were positioned in the TO/GA detent and the PF maintained nose-up inputs" (curious thing, TOGA, if PF was thinking being in overspeed).

Are we maybe reading different reports?

alex, thanks for posting that. It's nice to have that link handy again. It's been around this group since mere days after the accident. It's an excellent analysis. It'll be interesting to see if anybody sees anything more in it that would bear on this accident. (I suspect somebody was thinking of this and the BEA analysis of the weather might be why 200km off normal line of flight was mentioned.)

wozzo, I went back to the 17 Dec, 2009 Interim Report and found a description of the stall procedure. At altitude it's TOGA for thrust and slight nose down. So he did it half right. There is a valid question what he had in mind for his continue pull on the stick. And I suppose there is question whether he wanted TOGA for stall or for getting above it all. (If the latter, why did he almost level off after only 500' altitude gain?)

My understanding (which may well be incorrect) is that, when the a/p drops out, alternate law will maintain the pitch/roll status current at a/p disconnect. The implication in the report is that the right roll began after a/p disconnect, presumably as a result of turbulence. My understanding (again, possibly incorrect) is that the computers would have corrected the roll to the previous (presumably straight-and-level) setting without pilot input. But that doesn't explain why the PF believed he needed to get the nose up.

The question left by the report is why the PF did anything at all. Obviously there was a reason for what the PF did, even if not doing anything might have produced a better result. If it was the airspeed displayed on the right side display, it wouldn't be recorded in the FDR, which does seem to be a design oversight.

A related question is why the crew didn't work the QRH for unreliable airspeed.

I haven't gone back and re-read it, but far as I remember he didn't see anything out of the normal in the data he had at hand. The OAT was forecast around -46°C, and the actual data will be available from the FDR, including a complete temperature sampling all the way from FL380 to FL0 provided the probes could keep up with the rate of change.

The following pilot comment is probably pertinent, "... we’re in the cloud layer unfortunately we can’t climb much for the moment because the temperature is falling more slowly than forecast". I note from Tim Vasquez's profile chart that he has indicated the FL350 temp as -43°C.

The crew knowing the OAT was on the high side and they were level FL350 at 205 tonnes, had already formed the opinion that climbing to FL370 per the FP wasn't an option. So, why a few minutes later when the AP/ATHR disconnected did they engage in this "zoom" climb?

It would seem that they were in the anvil cloud out-flowing from the prime Cb's, and this cloud was carrying a lot of moisture just ready to turn into ice crystals as it struck the pitots etc.. Did they at any time get on a thermal elevator?? I don't think so ... the only elevators in use were the ones attached to the airframe.

For the record, Tim has stated that thermal updrafts can reach speeds of 4 ~ 5,000 ft/min, but as far as I am aware that didn't occur that night .. daytime, maybe.

There is much more to what happened than has been revealed, and I suspect the real meat will be in the detail.

The last recorded values were a vertical speed of -10,912 ft/min, a ground speed of 107 kt, pitch attitude of 16.2 degrees nose-up, roll angle of 5.3 degrees left and a magnetic heading of 270 degrees.

ground speed: 107 kt
vertical speed: -10,912 ft/min = -107 kt

Coincidence? Maybe.

The mathematician in me says this a/c achieved some sort of exotic aerodynamic stability during its descent. Wish I had more info about a/c heading during its descent.

Cabin Vertical Speed Advisory - revisited
 

Thanks to ACARS being free to transmit the CVS advisory in real-time, here is what actually happened:-

Two independent pneumatic safety valves prevent the cabin pressure from going too high (8.85 psi above the external ambient pressure) or too low (- 1 psi below ambient pressure).

* hcbn = 7350 – (750 ft/min x 251/60) or 7350 ft - 3138 ft = 4212 ft

As a 2.03625437 inHg pressure change gives approximately a 2036 ft altitude change, and as the external pressure is 1 psi more than the cabin pressure, the external or aircraft altitude (hacft) is simply:

* hacft = 4212 - 2036 ft = 2176 ft

2:14:16 - 2:14:28 = 12 sec > rate of descent = (2176/12) x 60 = 10,880 ft/min.
BEA's Rate of Descent at impact = 10,912 ft/min.

The 10,880 ft/min rate uses the earliest time the Cabin Vertical Speed advisory could have originated, i.e. coincident with commencing transmission of the preceding fault report message [02:14:16] with time of receipt 2:14:20. A further assumption is that the flight terminated coincident with the Cabin Vertical Speed warning receipt confirmation by the aircraft [02:14:28].

NOTE: WRN messages take precedence over FLR messages.
2:14:20 FLR/FR0906010213 22833406AFS 1,,,,,,,FMGEC1(1CA1),INTERMITTENT
2:14:26 WRN/WN0906010214 213100206ADVISORY CABIN VERTICAL SPEED

The final satellite link with AF447 terminated a few milliseconds prior to the aircraft's impact.

Descent angle
 

Good math, Cog. Maybe go further and calculate the AoA required for those parameters.

Then re-read my re-post about the Viper deep stall AoA and descent rate and indicated airspeed.

Hi,

Unreliable speed:
Airbus presentation dated 26-28 September 2006.
Unreliable Speed – Latest Improvements. Presented by Sourya Kahoul and Marie-Helene
Combes.
http://www.iag-inc.com/premium/Airbu...ableSpeeds.pdf