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What really happened aboard Air France 447

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Re: What really happened aboard Air France 447

#51

Post by hristov »

citricsquid wrote: post #6

The lack of reaction to "Stall!" implies one of two things; either it was broken and the sound didn't play or the complete lack of understanding about what the word "Stall" meant with the pilots. Has either of these been proposed and discussed? The author of this piece doesn't seem to touch on why they ignore "Stall!", unless it's been confirmed the sound had been heard (on the recording maybe?) and they did indeed u…

In many cases people do not mention the obvious. If there is a stall alarm blaring, I do not think any pilot would actually say "the stall alarm is on".

So I do not think it too surprising that nobody mentioned stall in conversation. Now about why they did not put the nose down, it seems either that (i) they were both under the impression that the electronic controls would not let them stall; or (ii) from their experience with smaller planes they thought they would be more pronounced shaking and other physical clues when the plane did stall.

Also it seems that they were much more scared of the storm than stalling so they just wanted to escape it.

Re: What really happened aboard Air France 447

#52

Post by breckinloggins »

sliverstorm wrote: post #35

Could they not simply have looked out the window and understood? Or simply felt gravity in their bodies? A 40 degree incline is pretty severe, wouldn't it be obvious?

Unfortunately, no. They could not look out the window because it was dark and they were in the middle of a storm. I doubt the sky looked much different IN the clouds as opposed to 10 ft above the ocean. Presumably, it would also be too dark and stormy to see the ocean even if they were right above it.

To understand why the answer to the rest of your questions is also "no", you have to understand the psychology of vertigo in situations like this (http://www.studentpilot.com/articles/medical_articles/articl...).

Re: What really happened aboard Air France 447

#53

Post by Terretta »

runningdogx wrote: post #29

I've followed the discussion of the AF447 investigation on several flight discussion forums. The PF (Bonin) apparently never became aware of his angle of attack (once the airplane fully stalled, AOA was absurdly high). He did not seem to be aware that his constant inputs had caused the Airbus's THS (trimmable horizontal stabilizer, horizontal flaps on the tail) to deflect to maximum in order to try to keep the nose u…

Almost all of this is in the article, and what isn't, takes some parsing to sort out. I would have found those bits of color more helpful if the additional info was related alone.

Re: What really happened aboard Air France 447

#55

Post by bdonlan »

sliverstorm wrote: post #43
jarcoal wrote: post #40

Earlier quoted context omitted.

Supposedly they do de-ice themselves, but that obv didn't work properly here.

Ah, I was not aware they already could. My next question is why not make themselves de-ice better? This maybe seems trollish or silly, but in all seriousness, if your sensors aren't good enough, first rule out improving the sensors before you try to compensate with the system.

According to the article's timeline, dual pitot failure occurred at about 02:10:06. Recovery of one pitot occurred at 02:10:36, and the other at around 02:11:03. That's about 30 seconds to recover one pitot, and 57 seconds to the recovery of the second. When you consider that this all boils down to melting off ice, that's not so bad, really. And if they hadn't royally screwed up their manual handling, it wouldn't have downed the plane - there is, in fact, a procedure for maintaining safe lift when airspeed indications are lost; somehow the copilots in command managed to screw it up, and continued to screw up even after the pitots recovered. The BBC tried replicating a pitot failure in a simulator, and when the sim pilots went by the proper procedure, there was no problem: http://www.youtube.com/watch?feature=player_detailpage&v...

So basically, this is human error, but exacerbated by a lack of training in cruise problems and poor feedback from the controls when the copilots gave conflicting commands.

Re: What really happened aboard Air France 447

#56

Post by nchaimov »

flyingkiwi wrote: post #31
fr0sty wrote: post #19

Earlier quoted context omitted.

This is a fantastic question. I can think of no situation where this behavior would be desireable, but then again IANAP

I am a pilot (a small one but instrument rated) - there's no time EVER that you want that, and I am shocked the Airbus does not have a warning that says DUAL INPUT BEING RECEIVED. At the very least, it should give priority to the left seat controls. Was really shocked to read the article.

It does: there's an audible warning that says the words "DUAL INPUT"

The English translation of the BEA's third interim report on the flight is available here: http://www.bea.aero/docspa/2009/f-cp090601e3.en/pdf/f-cp0906...

It includes the full CVR transcript at the end, which shows that the dual input alarm activated five times.

Re: What really happened aboard Air France 447

#57

Post by gameshot911 »

rguzman wrote: post #39
bdonlan wrote: post #34

Earlier quoted context omitted.

Surely he's been in exciting situations in simulators, at least? (And if not, he probably should arrange for some simulated excitement :)

oh yeah... due to a complicated set of fortunate circumstances i once got an observer seat during re-current simulator training (happens every 6 months). all the flying i've ever done was on ms flight simulator, but i know enough to read gauges and what not. it was so intense that even i was too stressed to finish paying attention to the whole session. lots of exciting situations there. and stop calling me surely.

It's "Stop calling me Shirley" :)

Re: What really happened aboard Air France 447

#59

Post by reledi »

sliverstorm wrote: post #43
jarcoal wrote: post #40

Earlier quoted context omitted.

Supposedly they do de-ice themselves, but that obv didn't work properly here.

Ah, I was not aware they already could. My next question is why not make themselves de-ice better? This maybe seems trollish or silly, but in all seriousness, if your sensors aren't good enough, first rule out improving the sensors before you try to compensate with the system.

I agree. I know little about aviation, but wouldn't it be better if the sensors would automatically de-ice themselves rather than only being de-iced at the pilots' command?

Re: What really happened aboard Air France 447

#60

Post by Splines »

afterburner wrote: post #46
sliverstorm wrote: post #35

Could they not simply have looked out the window and understood? Or simply felt gravity in their bodies? A 40 degree incline is pretty severe, wouldn't it be obvious?

In the dark, in a storm, you have no reference points. In a moving plane, your reference frame is further confusing. There are stories of pilots making a nice, 1-g bank turning the craft upside down and not noticing until it was too late due to white-out conditions. Gravity is only one of the forces acting on the pilots' bodies.

Aka a graveyard spiral:

http://en.wikipedia.org/wiki/Graveyard_spiral

This is what killed JFK Jr.

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