What really happened aboard Air France 447 • Hacker News Board

Re: What really happened aboard Air France 447

#351

Post by vannevar » Fri, Dec 09, 2011, 10:27 PM UTC

einhverfr wrote: post #128

bambax wrote: post #112

Earlier quoted context omitted.

What's missing from this article is the fact that the Captain chose to fly right into the storm, saying "on va pas se laisser emmerder par des cunimbs" (in essence: "fuck this storm") http://www.lexpress.fr/actualites/2/actualite/des-dialogues-... This is incredible hubris. Then, in the middle of the storm he leaves the two copilots alone, one of them quite inexperienced, and goes for a nap. He's obviously trying to…

IANA Pilot. I do make aerodynamically correct fixed-wing and lifting-body type paper airplanes, however, and I have had a LOT of fun playing with aerodynamics in this hobby. One thing to keep in mind regaring stall is that it's 100% dependent on angle of attack, not speed (something Popular Mechanics gets entirely wrong). What happens basically is that at a high angle of attack the air layer doesn't track the wing su…

One thing to keep in mind regaring stall is that it's 100% dependent on angle of attack, not speed...

While the degree of stall with respect to the wing is independent of airspeed, the effects of stalling on the aircraft are very much dependent on speed. Even with the wing in the process of stalling, it can still generate enough lift to keep flying if you're going fast enough.

Re: What really happened aboard Air France 447

#352

Post by pbhjpbhj » Sat, Dec 10, 2011, 2:15 AM UTC

lutorm wrote: post #261

yew wrote: post #17

Earlier quoted context omitted.

I was thinking of ". . .even though the word "Stall!" will blare through the cockpit 75 times." Looking back over it, I suppose that's not quite what that means. . .

No, it's exactly what that means. Search for the youtube link to the Aeroperu recording above and you'll be able to hear how much blaring there is.

Which the pilot and co- don't know to trust as the altimeter and other instruments are giving false readings (listen to that recording, it's all due to the instruments being taped over by ground crew and the pilots missing it on pre-flight checks).

If you've determined that the stall warning is false I imagine it's hard then to back out and stop filtering that noise out; particularly when you're concentrating very hard on something else. Someone mentioned a case where the pilots crashed because they were attending to a landing gear problem and so missed the lack of fuel.

I wonder how men/women differ in these pressure situations too. IME women generally appear to handle multi-tasking and interrupts better than men do.

Re: What really happened aboard Air France 447

#353

Post by jarek » Sat, Dec 10, 2011, 4:46 AM UTC

Caballera wrote: post #299

jarek wrote: post #131

Earlier quoted context omitted.

The Popular Mechanics account of AF447 leaves out some quotes and doesn't explain their content very clearly, unfortunately, but it appears they were doing that, more or less. "02:11:37 (Robert) Commandes à gauche! Left seat taking control! [...] At any rate, Bonin soon after takes back the controls." Sometime after 2:12:15: "As the plane approaches 10,000 feet, Robert tries to take back the controls, and pushes forw…

i don't know these people and I'm not a pilot, but is it possible the Bonin wanted to crash the plane? I find it hard to believe that he would continue to pull back on the stick almost the entire time and not 'share' that information, and after Robert took control (by stating 'Give me the controls!'. Just wondering if this is something that would be looked into.

Technically possible but seemingly unlikely. I'm leaning towards Occam's razor here: that would be an awful lot of acting fairly consistent with panicked, unexperienced actions, and if you're a pilot it's not exactly difficult to crash the plane if you want to. Additionally, the decision to fly into the storm wasn't Bonin's, so if he did decide to crash the plane in this manner it would have been a very rapid decision, or a result of pretty specific deliberations like "next time the computer goes into alternate mode and there is confusion and panic in the cockpit I will do it," which again runs against the razor.

Re: What really happened aboard Air France 447

#354

Post by Klinky » Sat, Dec 10, 2011, 6:18 AM UTC

konstruktor wrote: post #333

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…

> "This can't be happening!" I want a device that gives me an electric shock every time I think or say this. If one can restructure one's cognitive habits in a way that replaces thoughts like this with thoughts like "What would explain this? Is this reasonable? What are the alternaives? How can I check this?", many errors will be avoided.

His statement was made out of exasperation 4 seconds before he died. There is very little he could have done to change his fate at that point.

Re: What really happened aboard Air France 447

#355

Post by Klinky » Sat, Dec 10, 2011, 6:34 AM UTC

brazzy wrote: post #336

georgemcbay wrote: post #315

Earlier quoted context omitted.

I am no aviation expert, but according to other posts here the stall warning may have been ignored because Bonin didn't register that they were in alternate law. If they weren't in alternate law, the plane would have automatically limited the amount to which he could pull back. The most obvious solution to me, if all of that information is accurate, is that there should be a distinct audio stall warning for alternate…

It seems like that when analyzing this accident. If you analyze another, there may be 2 or 3 other things that would seem "pertinent enough information to push it front and center". And yet more for a 3rd accident. The problem is that making something more noticeable automatically makes everything else less noticeable...

The two things that seem to big huge contributors to the crash are that the pilots may not have realized they were in alternate law soon enough & one or both pilots did not realize that one of them was holing the stick back stalling the plane.Both of these seem like glaring UX & training issues.

It does not appear that it's very clear when the plane goes into alternate law & it does not appear they receive much training on how to fly in alternate law. Even if they do receive training, you probably do not want your most novice pilot handling the controls in alternate law. Additionally the averaging of the inputs seems to be the most obtuse way for pilots to realize mismatched inputs.

Re: What really happened aboard Air France 447

#356

Post by reddit_clone » Sat, Dec 10, 2011, 9:19 AM UTC

furyg3 wrote: post #152

bambax wrote: post #118

Earlier quoted context omitted.

> Add a display that shows the current positions of both control sticks Yes! From the article: " As the plane approaches 10,000 feet, Robert tries to take back the controls, and pushes forward on the stick, but the plane is in "dual input" mode, and so the system averages his inputs with those of Bonin, who continues to pull back. If this is true, it's insane. What does it mean to "average" the inputs of both pilots…

I was shocked that new airplanes use joysticks are just simple inputs and don't give (some) feedback on the current state of the current control surfaces or the state of the other joystick. This seems like a "feature" of analog controls that you'd want to take forward to fly-by-wire systems.

For me the 'averaging' of two controls seem totally bizarre. One pushing forward and one pulling back and the computer thought that was OK?

My fear of flying is reaching new heights.

Re: What really happened aboard Air France 447

#357

Post by omegant » Sat, Dec 10, 2011, 2:55 PM UTC

yardie wrote: post #147

sandee wrote: post #63

Earlier quoted context omitted.

>at night, over an ocean, in a storm, with no visibility, in possibly significant turbulance Instead of finding out strategies on how to fly under these circumstances, why can't the plane change its course, if they anticipate the flying route to have these conditions. How about running some reconnaissance drones in the popular routes if they suspect a bad weather and want to check out. Or try out better weather monit…

1. This is a region that is quite regular with thunderstorms. The captain probably assumed this was like any other storm in this area any other day of the week. 2. This route is at the upperlimit this plane configuration can fly. If they had to reroute they would need to stop and refuel in another country, possibly Spain, Senegal or Morocco. I assume the captain didn't want to do this and soldiered ahead.

You simply don't fly through a thunderstorm, as you simply don't drive through A concrete wall at 100mph. No matter how short you are on fuel.

Re: What really happened aboard Air France 447

#358

Post by omegant » Sat, Dec 10, 2011, 3:04 PM UTC

akira2501 wrote: post #98

anrope wrote: post #79

Earlier quoted context omitted.

Up to this point, the situation was playing out in a sadly too common case of pilot error, pilot inexperience, which makes up a huge portion of aviation accidents. When I read about the dual input averaging, I literally exclaimed "what?!". I can't believe that, for all the strict standards that flight control software must meet, nobody called this out as a dangerous idea?

Precisely.. I'd also like to know under what circumstances this would actually be used, and be a useful safety feature to have implemented. At the very least, there should be a significant warning in the cockpit when "dual input" mode is active. That is an incredibly dangerous "feature."

There is a loud "dual input" voice + a red light just infront of you. Also if you push the red button on the sidestick and keep it pressed you override all te commands of the other one. This has several reasons, taking away the control from a disoriented pilot or disengaging a malfunctioning sidestick which is commanding random inputs.

Re: What really happened aboard Air France 447

#359

Post by omegant » Sat, Dec 10, 2011, 3:32 PM UTC

rguzman wrote: post #21

my dad is a captain, very experienced -- flies 777s, has > 20k hours and is trained in both airbus and boeings. over dinner i once asked him "so what's the most exciting or difficult situation you've even been in?" "hm... nothing i can think of, it is all pretty boring, really" "i mean c'mon, there's got to be something!" "you see? if you do things by the book plus a little on the safe side it usually works out that…

Well ask your dad about landing in short runways during a thunderstorm with strong gusting cross winds + contaminated runway. If he didn't have a rush with that...

Re: What really happened aboard Air France 447

#360

Post by konstruktor » Sat, Dec 10, 2011, 3:34 PM UTC

Klinky wrote: post #354

konstruktor wrote: post #333

Earlier quoted context omitted.

> "This can't be happening!" I want a device that gives me an electric shock every time I think or say this. If one can restructure one's cognitive habits in a way that replaces thoughts like this with thoughts like "What would explain this? Is this reasonable? What are the alternaives? How can I check this?", many errors will be avoided.

His statement was made out of exasperation 4 seconds before he died. There is very little he could have done to change his fate at that point.

Still an indication of bad mental habits. And it doesn't strike me as out of line with his actions (complete disregard of the empirical information he had) the minutes before.