AF447 wreckage found

[mastercaution1]

WX Radar

My question!
What was the WX-Radar showing? How big was the cell there going thru? Green, yellow or red? Is there anywhere a reconstruction of the picture?

[predictorM9]

Originally Posted by britfrog

what faulty logic? the only faulty logic was the pf who looked at the vsi which was pinned to the bottom, and he couldnt deduce that they were fully stalled out. a very elementary mistake

Actually if you look at the variometer data from the BEA report, it is not pinned to the bottom, but also flickers too.

Conclusion:
- failure from the pilots to realize that the variometer data was almost right even if it flickered
- failure from the pilots to realize that the lack of stall warnings was wrong because they flickered

that's it! pilot failure. case closed.

[DozyWannabe]

Originally Posted by predictorM9

Also, what matters is not the fact that it sounded for 57 seconds straight. What matters is the fact that pilots push the stick forward and then the stall warning sound. If you were piloting this plane with all the other faulty sensors, wouldn't you start to think that the stall warning is faulty too?

The only faulty sensors were the pitots, and then only briefly, so to say "all the other faulty sensors" is a bit disingenuous. At this point I believe a competent pilot should disregard all other annunciations other than the thrust settings and the pitch as displayed on the ADI (double-checking the ADI with the standby instrument if you're unsure). Once you've got those in the right ballpark you should know you're going to be OK.

This kind of behavior of the stall warning is only caused by the faulty logic, and the BEA does not seem to want to address this...

If they didn't want to address it, they wouldn't have mentioned it in the report, but the important point (which goes back to your first paragraph) is this - simply teaching stall warning and avoidance, as had been done prior to this accident, simply isn't enough. Stall recognition and recovery procedures should be a mandatory part of recurrent training, which you'll notice has become something of a hot topic in the industry over the last couple of years.

Originally Posted by predictorM9

I don't see why we should blame the pilots for discarding a warning system that is behaving erratically and against your intuition (nose up= stall, nose down=no stall).

Again, only the press are saying that the report is "blaming" the pilots. If you read the report itself, it becomes pretty clear that the BEA considers this an industry-wide issue that should be clarified and adopted by manufacturers and airlines alike.

I'm beginning to wonder why the press are unilaterally oversimplifying the interim findings this way - you only have to look at the report itself to see that it is a very dry document that does not apportion blame as such, but does criticise the apparent lack of CRM and flying knowledge exhibited in the flight deck. It isn't blaming the pilots, it's saying there's likely a systemic problem that needs to be addressed - unfortunately that doesn't make for a "sexy" byline.

[carlosgustavo]

Flying high is a new experince. High altitudes stalling is not very frecuent To practice.Has anyone here done it¿ I wonder how low density of the air and the inercia of the stall due to the long time stalling affects the recovery tecnique.

STALL WARNING MUST ALWAYS WORK. Its unveliable that on the Airbus with that pitot probe on icing condicions doesnt.

Its funny for me how people blame the pilots because the stall warning sound for 57sg and they didint recognize the stall. Dont you understand that when the stall warning stops means NOT STALL, but the aircraft wad actual stalling.

This is what should be:
Sound of the stall warning should mean STALL
Not sound of stall warning should mean NOT STALL


If you relay on stall warning when the sounds stops should be that you are out of stall. I think they pilots of the Airfrance understood that the stall warning was not working right, but I think they probably felt overspeed due To de strong turbulence and icing they were in.

[timpara]

Apologies if this article is already familiar in this domain, but
The Case For An Angle Of Attack Indicator | Air Safety Week | Find Articles at BNET

seems to summarise quite well the conditions under which an AOA indicator available to the pilots is useful. Good to see it the the BEA recommendations.

[aguadalte]

DozyW:

Tactile feedback will come into it, yes - but it's worth remembering that the same thing happened to the Birgenair 757 which had interconnected yokes, and the psychological impact and tragic result was much the same.

Was there a UAS procedure training in force at that time? (I honestly can't remember) As I said before, my experience with Boeing ended long time ago in the early 90's and I can't remember training UAS at that time.

[before landing check list]

Timpara, I agree with you 100%. That is exactly what I was saying in an earlier post. Attitude and speed are secondary to the AOA in relation to the performance of the wing.

[ross_M]

From the BEA report:

Until impact now the stall warning activates when the nose is lowered and silences when the pitch angle increases. FDR data suggest that as soon as the stall warning activates the pilots react with nose up inputs which cause the stall warning to silence again.

I can hardly blame the pilots. If something you do silences a warning there's a natural temptation to keep on doing it.

Horrible systems design I say.

[RansS9]

One of the problems highlighted by the investigation was inadequate pilot training.
Why don’t the various National Pilot Unions alone or better still in concert devise their own Standards of Simulator Training for different categories of commercial flying; then use this as a benchmark to judge the quality of training given by companies. In this era of transparency publish the results on the web, with a section for the company to reply to any criticism if they wish, and give the Public / Journalists more information to make their Carrier decisions.
Perhaps this is already done; perhaps not. It would at least open the area for more debate and scrutiny.
Just a thought

[Feathers McGraw]

Anyone know if an English translation of the 3rd interim report in French (the 117 page pdf) is going to appear?

Difficult to grasp the details when my technical French is not up to the job.

[Loose rivets]

Sim training will only take you so far. I refer again to Davis' impassioned plea to get ordinary airline pilots some extraordinary training - in real aircraft.

My original edition does not include this - has anyone got one of the later editions they could copy a quote from? (I read an F/O's in about 1999)


While flying in a 'retirement job' I found myself in a twin Turboprop with a full load of passengers, hopping from Aldergrove to City, at night, in rough and rainy conditions.

The stall warning went off, with shaker and siren.

It's hard to describe how that 7 mins or so of that beaten-into-me-brain pair of warnings affected me, even after thousands of hours in command on Turboprops, and really steeling myself against what had become an almost certain false warning. For a very long 60 seconds, it was almost impossible to believe the instruments.

Apart from the fact we were near lumpy ground, the 447 crew's sensory inputs and scrolling data were I would think, much more confusing. I feel deeply sorry for them, but do feel that they should have nailed attitude and power within a band appropriate to that aircraft as an absolutely fundamental part of aircraft handling.

[sebaska]

Originally Posted by Graybeard

According to many prior posts here, the Stall Warning shuts off below 60 kt IAS. Why they have IAS input to SW is beyond me. The DC-10, for example, uses only AOA for SW.

Stall AOA is ~7deg when high&fast and ~16deg when low&slow.
Besides, AOA vanes are designed and calibrated for situations when air comes from generally front direction, not side or bottom. AOA was severe enough to cause Pitot readings off, variometer indications got flaky, etc.

Originally Posted by predictorM9

I completely agree. As long as the plane is in the air there is always 60 kts of relative wind, even if the angle of attack is so high that the pitot measure wrong speeds.

Nope. It's perfectly possible, as evidenced by previous accidents, to get airspeed below 60kts in a large plane (some poor guys happened to get negative airspeed before they crashed). But I agree that the real airspeed was above 60kts in this particular case.

Originally Posted by predictorM9

The fact that they certified the logic behind this is for me a huge mistake. As long as the AOA is not insane it doesn't matter. But if the aircraft is capable of 45 degrees AOA, they should do a logic that also works in this case

Certification does not bring much attention to situations so far away from flight envelope. Many airframe designs are considered totally unrecoverable even by heroic measurements when stalled so severely, yet they get certified.

Originally Posted by predictorM9

failure from the pilots to realize that the lack of stall warnings was wrong because they flickered

The stall warning was on for long enough to take proper action. It's debatable if the airplane could be recovered if they initiated proper action after stall warning continued for the whole minute.

You, and many posters here concentrate on what happened after the plane has severely stalled. But from a flight safety PoV things were already critically bad. Dealing with problems during "falling out of the sky" phase won't improve safety much (if at all).

What is really important is how it entered the stall and how there was no immediate proper attempt at unstalling it. Aural stall warning was active then, attitude indication was good, vario was good, even speed was good at least on PM's display and backup (ISIS) display.

So, if even, there is some human interface problem pertaining to that phase of flight ain't aural stall warning silencing itself when attitude gets so far away from flight envelope that pitot probes stop working.

[DozyWannabe]

Originally Posted by aguadalte

Was there a UAS procedure in force at that time? (I honestly can't remember)

Yes, because there had been several UAS incidents with the Thales AA pitots. There was a specific bulletin on the subject if I recall correctly.

@ Feathers, it's due later this week.

[ross_M]

some poor guys happened to get negative airspeed before they crashed

What exactly is negative airspeed? Plane flying backwards?

So, if even, there is some human interface problem pertaining to that phase of flight ain't aural stall warning silencing itself when attitude gets so far away from flight envelope that pitot probes stop working.

Did the pitots stop working because of the snow or being away from envelope?

[Denise Moore]

What does it say?

Unfortunately the BEA's report isn't available in English yet.

But from the discussions here it seems to still be silent on many things.

Did the pilots say nothing during the last three minutes? Because I have not seen anything mentioned.

The BEA did, apparently, say the plane was fully and completely responsive throughout, so how did they explain the THS being apparently stuck up, ignoring the
down instructions (of which there were at least a few).

[takata]

Hi ross_M,

Originally Posted by ross_M

Did the pitots stop working because of the snow or being away from envelope?

At first, because of ice crystals. This issue #1 lasted a bit less than 1 minute and it was cleared before they were actually stalled (but stall warnings were not affected by this fault).

Later in the sequence, alpha went so high (above 35°) that both pitot and alpha probes were out of boundaries (hence, Stall warnings stopped). issue #2 happened 40-50 seconds after the full stall developed.

The main confusion is due to #2 starting too closely after #1, the crew being not able to deal with any of them (neither UAS nor Stall).

[camel]

it does seem weird that the PF in the RHS was not wearing any kind of seat belt,having warned the cabin crew of turbulence ahead.. i understand Airbus provide a nifty table where the yoke sits on most other aircraft

is it a possible scenario that he had the seat pushed back and was tucking into his dinner? so that when the Auto Pilot/Auto thrust clicked out he had to reach out further than usual to grab the side stick ...plus maybe with a tray full of food in the way ... apologies if this has been done to death before.. just a thought .

[Mimpe]

at least the Airbus engineers now know an AoA of 35 degrees positive is possible in commercial flight, and it shouldnt pose a condition for the silencing of a stall alarm......

I bet there are lot of other limiting software conditions that pose create additional risk at the very edges of the improbable flight envelope , where one needs the info the most.

[mach2.6]

CVR last minutes of flight

I was watching French TV 5 Monde last week, and they aired the actual conversation of the last few minutes of the flight, narrated by an announcer with text superimposed over a graphic of the cockpit. All three crew members were present in the cockpit. It was clear that they were confused and, in fact, could not believe what was actually happening. One crewmember (maybe the captain, but I'm not sure) repeated several times "pull up" and "pull". My French isn't very good, so I was concentrating more on the speech rather than which crewmember said it. Maybe some of our friends on the East side of the Pond have some contacts at TV 5 Monde and can get the video. I can't find it on their website.

[SaturnV]

Feathers McGraw, the English language version will supposedly be available on Wednesday.

Denise Moore, the pilots said a lot. There is a transcript of the conversation and a translation of the French in the Tech forum.