Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

What really happened aboard Air France 447

popularmechanics.com

Post reply on HN
Print view View original

191–200 of 374 posts

Re: What really happened aboard Air France 447

#191

Post by gnaffle »

SagelyGuru wrote: post #174

Hmmm, lovely reading on a day I am due to fly with Air France across the globe! It is easy to blame Bonin for being such an idiot and pulling on the stick all the time but it is a natural reaction, just like inexperienced drivers continuing to lock the brakes while skidding off the road. How many die that way every day? More worrying to me is that the whole plane control is inherently and crazily unsafe. Whatever wer…

At least you can find some comfort in that AF447 was the first fatal accident with the type, and that there's been continuous improvement throughout the years (including replaced pitot probes). But bigger design problems might have gone unadressed because it's difficult to justify a major change in a certified design until it causes an accident.

Re: What really happened aboard Air France 447

#192

Post by soren_dahl »

bambax wrote: post #146
einhverfr wrote: post #128

Earlier quoted context omitted.

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…

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?

Re: What really happened aboard Air France 447

#194

Post by mikecane »

I'm no pilot, and I haven't read the long discussion here, but I can't see how the pilots can be blamed. That Airbus has nonsensical design. Asynchronous sticks, so the other one in the seat couldn't see the other stick being pulled back? Then averaging of the async controls, allowing one stick to work against the other? As for "alternate law," why was there no alarm like the Stall warning to repeatedly tell those in the cockpit that controls were now in Manual Override? Who thought any of that was a good idea? It was bad design that doomed that plane, not the humans inside trying to deal with a design that could thwart anyone.

EDIT: Also, I must add that it seems to me just to be able to engage with reality, a bloody string with a weight hanging from the cockpit ceiling would have shown that the airliner was climbing, from the angle it was hanging. Low-tech and it sounds stupid, but with cockpit crew so alienated from physical reality due to computer mediation and no visual cues due to the clouds, it would have immediately shown them what was really happening.

Re: What really happened aboard Air France 447

#196

Post by jsmcgd »

Panic seems to be so debilitating in situations like this as stress severely diminishes to ability to think.

Is it worth considering making certain fast acting drugs available to professionals that operate in life-threatening environments that would stop or minimize the stress response?

I'm not sure if such a drug exists, one that might reduce stress but not also impair other cognitive functions. But it might well be extremely useful. I can't think of any situations where the stress response is useful in a complex environment.

Re: What really happened aboard Air France 447

#197

Post by robert_mygengo »

blinkingled wrote: post #18

The men are utterly failing to engage in an important process known as crew resource management, or CRM. They are failing, essentially, to cooperate. It is not clear to either one of them who is responsible for what, and who is doing what. I have read a few other transcripts from crashed planes and this seems to be the most common and significant contributor. I see variations of this problem almost daily in my day to…

I don't want to in any way refute the referenced article or the findings of the air crash investigators, because clearly the pilots here behaved incorrectly and I am just an outsider.

However I think it's worth at least mentioning that both airlines and aircraft manufacturers have a vested interest and significantly more resources to put behind demonstrating that pilot error is the primary cause of any accident.

For instance in this case you have... • poor training (pilots unprepared for alternate law) • possibly poor UI (de-coupling of controls, insufficient communication that aircraft had lapsed to alternate law) • small-scale systems failure (pitots)

vs • incorrect response and continued failure to understand aircraft attitude (in turbulence, with no visual cues, in a situation which 'fooled' three pilots)

...which makes it an interesting one for manufacturer and airline to definitively defend, but I would guess that they can and will absolve themselves from liability.

Re: What really happened aboard Air France 447

#198

Post by worldvoyageur »

What impresses me most in this tragedy is its illustration of the culture of rigorous process to get to the bottom of what happened so that lessons can be learned to make flying safer. Relentlessly followed for decades, in all countries, this culture has made large airliner air travel the safest way to get between two distant places.

Ideas really can change the world.

Re: What really happened aboard Air France 447

#199

Post by maeon3 »

scarmig wrote: post #36
maeon3 wrote: post #27

Pilot stalls the plane out of panic to get out of the storm, ignoring 75 reminders that you are stalling and losing altitude, does nothing to remedy the stall until it is too late. I expect blunders like that from drunk drivers.

If only. Unless you empathize with mistakes like this, it's very difficult to prevent them in the future. You're always going to have people who make mistakes in any system you design. The trick is to design the system so that mistakes are easily corrected, even when multiple ones are compounded. It's akin to someone dropping a table of unrecoverable user data. Sure, it was dumb on their part, but why the hell is it…

The problem was Panic. In a panic situation humans revert back to a time when we need to run away from the bear that is chasing us in the woods. To fix this, I propose a "panic awareness system", where the machine says: "Don't panic". and tells the pilots to take some anti-panic medicine.

Re: What really happened aboard Air France 447

#200

Post by Angostura »

citricsquid wrote: post #13
yew wrote: post #8

Earlier quoted context omitted.

The articles says it's audible on the recording. Stall alarms are usually very loud. I can't speak for Air France, but in general aviation the word "stall" (in English) is of global significance. I imagine they thought it was malfunctioning, or simply didn't think about it in the heat of the moment.

They don't explicitly state that it is something you can hear in the recording, I made the assumption that the "blackbox" contain not just an audio recording but a log of the computer system -- what actions it took, which is how they know the co-pilot was pulling back the entire time -- and they're basing it off of that. Although the way they phrase it (reading back through the relevant paragraphs now) with the assum…

I would imagine that if the audible stall warning had failed, this would have been a very significant issue that would have been flagged up at the head of the report.
Post reply on HN