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What really happened aboard Air France 447

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Re: What really happened aboard Air France 447

#221

Post by mtts »

soren_dahl wrote: post #192
bambax wrote: post #146

Earlier quoted context omitted.

A commenter below (cellularmitosis) makes a very interesting point: Bonin may not have realized he was in "alternate law" (let's call it "mode" instead of "law"). In "normal mode" the computer will not let pilots stall the plane, whatever they do; it will accept the commands up to what it considers dangerous. There's an "envelope" of acceptable plane movements; pilots can move inside this envelope but not outside of…

There's a school of thought that says that user interfaces should be modeless, I wonder if the concept of a mode here is a fault in the design of the HCI as well as insufficient training?

Oh no ... we are NOT turning this into another Vi vs Emacs flamefest

;-)

Re: What really happened aboard Air France 447

#222

Post by nikcub »

mtts wrote: post #218
nikcub wrote: post #188

Earlier quoted context omitted.

ye no shit, and I am thinking through how the situation gets to a point where he can forget all that and keep pulling the stick back up

He panicked. What's there not to understand?

how about why do people who have been thoroughly trained and have spent thousands of hours at the control suddenly forget everything they know in an emergency?

I am pretty certain that when the full report here is released it won't stop at 'he panicked' and that this accident will have ramifications for the entire industry

Re: What really happened aboard Air France 447

#224

Post by jrockway »

gnaffle wrote: post #167
StavrosK wrote: post #154

Earlier quoted context omitted.

Ah, yes, I read that too. It was so frustrating that the pilot kept pulling up all the time, it makes no sense. You'd think that at some point he'd stop and reassess, but I guess he was too confused and shocked to do it...

Yes, maybe a combination of shock, confusion or distrust in the instruments was a factor. It will be interesting to see what the human factors group of the investigation comes up with. I'm sure that the flight training will also be investigated, there has been concerns that improper stall recovery technique is being taught by some instructors: http://www.caa.co.uk/docs/33/012010.pdf (And of course, in planes that are…

(And of course, in planes that are not certified for stalls, you can't really practice full stalls and have to train on approach to stalls instead.)

Of course, very little airliner training happens outside a simulator, which can you can stall without damaging anything.

Re: What really happened aboard Air France 447

#225

Post by antoinehersen »

einhverfr wrote: post #130
antoinehersen wrote: post #70

Earlier quoted context omitted.

Not changing course like almost all other flight that night was their first mistake.

I noticed that the article suggested their weather radar was incorrectly set up, so that might be their first mistake.

They should have pay extra attention to the weather since this region of the globe is prone to the worst storm. They even aknowledge it in the recording.

Re: What really happened aboard Air France 447

#226

Post by mikeash »

flyingkiwi wrote: post #32
mikeash wrote: post #22

Earlier quoted context omitted.

IAAP (not commercial) and that sounds like an awful way to do things. An important aspect of cockpit resource management is to know who is controlling the airplanes, and part of that is always positively verbally transferring control, with confirmation. "I have the plane." "You have the plane." There is no situation where you want two people to both have input at the same time.

IIRC, that was lesson 1, minute 2 (right after take-off). The previous commenter who said that wouldn't think to ask because it is akin to asking 'is the computer plugged in' is probably right (though the captain should have noticed it when he was observing). Serious design flaw, and tragic human error with devastating results. :(

I'm actually mildly surprised that it waited until you were in the air. I always brief that before takeoff whenever I take another pilot along. But yes, very basic stuff in any case, and amazing that they were not following this standard procedure.

Re: What really happened aboard Air France 447

#227

Post by jrockway »

eftpotrm wrote: post #207
aperiodic wrote: post #177

Earlier quoted context omitted.

GPS gives you speed relative to the ground, not speed relative to the air, which is what's important for aerodynamics.

Yes, but when groundspeed with a slight lag is all that's available is it really that much worse than nothing, which seems to be the failure mode at present? I stress I'm not a pilot and I'm sure you'd want to have a Big Flashing Warning Light telling you that ground speed air speed, but there'd seem to be some benefit over nothing at all.

The ground speed is not useful information. You can be moving backwards relative to the ground and still be overspeed. The only thing that matters to the airframe is the airspeed, and the only way to know the airspeed is to sample the air around the plane.

Re: What really happened aboard Air France 447

#228

Post by antoinehersen »

jforman wrote: post #99
Klinky wrote: post #30

Co-pilot Robert, after finally getting full control back from Co-pilot Bonin: "Damn it, we're going to crash... This can't be happening!" Co-pilot Bonin, who had been pulling back & stalling the plane during the crisis: "But what's happening?" Pretty much sums it up. I am thinking that perhaps Bonin had shellshock & may not have even realized he was holding the stick back. Perhaps the more experienced Robert didn't t…

- Add a display that shows the current positions of both control sticks. Add an alarm when the two sticks are not within a certain margin of the each other, if both are engaged. Such as if one is full forward & the other is full back. This was my first thought as well. Confusion in one pilot was allowed to cause confusion in the second pilot, because he didn't realize that his partner was doing something unexpected a…

You can display so much information before you add to confusion in a high stress situation. Haptic feed back could be useful.

Re: What really happened aboard Air France 447

#229

Post by jrockway »

LaGrange wrote: post #148
nodesocket wrote: post #94

Earlier quoted context omitted.

This one feature may have prevented the crash. A indicator light, saying the plan is in "alternate law" mode, and SHIT can go wrong, very quickly. Also an alarm in the pilot resting area that would relay when warnings are detected like stall or switching to alternate law.

Okay. This is how the cockpit apparently looks: http://www.pbase.com/image/47231836 Where are you going to stick the indicator light so that it's impossible to ignore it or mistake it for something else.

Typically there are two lights, master caution and master warning, that indicate a problem. From there, the details can be read on another screen. Additionally, there are voice alarms for critical events, like "Traffic! Climb now!" or "Fire! right engine!".

I don't know how an Airbus notifies the crew of the switch to alternate law, but I'm willing to bet that the master caution light comes on.

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