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What really happened aboard Air France 447

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Re: What really happened aboard Air France 447

#31

Post by flyingkiwi »

fr0sty wrote: post #19
greiskul wrote: post #14

Earlier quoted context omitted.

Which raises a very good question, when would you ever want that joystick behaviour?

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.

Re: What really happened aboard Air France 447

#32

Post by flyingkiwi »

mikeash wrote: post #22
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

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. :(

Re: What really happened aboard Air France 447

#33

Post by weaksauce »

greiskul wrote: post #14
jeffbarr wrote: post #7

Earlier quoted context omitted.

According to the article, the input from the two joysticks is averaged.

Which raises a very good question, when would you ever want that joystick behaviour?

True. But, how would you want to handle the situation of two equally competent(at least in the eyes of the employer) co-pilots vying for control? should it always go to one? always go to the other? have a switch controlled? controlled by whom? not easy questions if you ask me.

edit: I actually can't think of a good way to do that other than have a manual switch on the console that would switch between the two controls. anything else seems amazingly bad.

Re: What really happened aboard Air France 447

#34

Post by bdonlan »

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…

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

Re: What really happened aboard Air France 447

#36

Post by scarmig »

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 possible for you to lose all your data from a single mistake?

Re: What really happened aboard Air France 447

#37

Post by rguzman »

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.

way too easy for you to say without being in the situation.

heavy turbulence, no visibility, confusing situation, very likely that he was disoriented, operating a very complex set of computer programs hooked up to a very complex set of physical controls that have a myriad of potential configurations and points of failure while trying to debug it at the same time in a panic and making quick decisions.

from his vantage point, it is likely that the stall warning is a symptom of something malfunctioning and not an actual stall.

that said, i thought that "if stall, you push forward" was instilled into pilots to the point of 2nd nature. i'm very surprised at the reaction to the stall warning.

Re: What really happened aboard Air France 447

#38

Post by sliverstorm »

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…

Making a computer that can fly without airspeed makes less sense to me than making an airspeed sensor that either doesn't ice, or can de-ice itself. Is that so impossible?

Re: What really happened aboard Air France 447

#39

Post by rguzman »

bdonlan wrote: post #34
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…

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.

Re: What really happened aboard Air France 447

#40

Post by jarcoal »

sliverstorm wrote: post #38
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…

Making a computer that can fly without airspeed makes less sense to me than making an airspeed sensor that either doesn't ice, or can de-ice itself. Is that so impossible?

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