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What really happened aboard Air France 447

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Re: What really happened aboard Air France 447

#171

Post by mtts »

Simon_M wrote: post #158
nikcub wrote: post #110

Earlier quoted context omitted.

the other similar incidents are Birgenair Flight 301, where the pitot tubes were blocked because of insect nests, resulting in pilot confusion: http://en.wikipedia.org/wiki/Birgenair_Flight_301 and Aeroperu Flight 603, where the pitot tubes had been covered by maintenance workers and not removed prior to takeoff, also resulting in pilot confusion and lack of confidence in instrument readings: http://en.wikipedia.org/…

Considering how many incidents there seems to be due to the loss of these airspeed sensors it seems crazy not to have an additional, different method of calculating airspeed. Is there a reason GPS is not suitable here?

Given the speed at which the readings in my android phone update while driving a car, I'd say yes.

Re: What really happened aboard Air France 447

#172

Post by alpyne »

Simon_M wrote: post #158
nikcub wrote: post #110

Earlier quoted context omitted.

the other similar incidents are Birgenair Flight 301, where the pitot tubes were blocked because of insect nests, resulting in pilot confusion: http://en.wikipedia.org/wiki/Birgenair_Flight_301 and Aeroperu Flight 603, where the pitot tubes had been covered by maintenance workers and not removed prior to takeoff, also resulting in pilot confusion and lack of confidence in instrument readings: http://en.wikipedia.org/…

Considering how many incidents there seems to be due to the loss of these airspeed sensors it seems crazy not to have an additional, different method of calculating airspeed. Is there a reason GPS is not suitable here?

It can't give you the relative speed of the air around the aircraft.

Re: What really happened aboard Air France 447

#173

Post by brazzy »

sek wrote: post #163

One question: Why are they not speaking English? I heard from fatal command mistakes with pilots an Asian country and now everyone has to speak English. Is this again some stupid patriotism thing (i am German, i know the French attitudes), but i seriously thought to prevent command errors everyone has to speak the international aviation language.

You seriously believe that command errors are less likely when two people communicate in a foreign language, compared to a shared native one?

Re: What really happened aboard Air France 447

#174

Post by SagelyGuru »

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 were the designers thinking, making the two sets of controls without cross-feedback and even 'averaging their inputs' ?!? Whatever were they thinking introducing flabby delays between stick movements and control surfaces? Ever tried to play a computer game with a two seconds delay of the controls?

The actual cause of the crash is this. There were three pilots trying to fly that plane at the same time: the computer, plus the two co-pilots. I guess four, if you include the captain chiming in from the back. Neither of them had any information or understanding or confidence about what the others were doing, due to no particular fault of their own. In such circumstances, adding and withdrawing auto-pilots, plus adding different 'computer modes' is totally insane and only adds to the confusion.

My conclusion: design fault (over engineering)

Re: What really happened aboard Air France 447

#175

Post by bulte-rs »

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…

That last thing is the most important thing to notice since this is what most people think is the main result of air crash investigations: making a change to break the event chain leading to the incident.

In this case there were probably a number of human errors, a.o: not noticing speed restrictions on the speedtape (even in alternate and abnormal alternate law/mode these are present, although Valpha max and Valpha prot are removed a barberpole is present up to Vstall warning) and 'ignoring' the nose-down moment the airbus tries to induce in a low speed situation.

Possibly some design errors in the form of the alpha-floor protection removed in alternate law/mode.

Seems like there is a lot to learn from this investigation for both pilots and manufacturers and although it might seem harsh and insensitive (believe me, it's not; I've lost friends due to an aircraft crash) I am actually looking forward to the 'final incident reports'.

Re: What really happened aboard Air France 447

#176

Post by einhverfr »

joshAg wrote: post #135
weaksauce wrote: post #33

Earlier quoted context omitted.

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 control…

perhaps have the plane decide which input seems more rational, then announce who has control.

Sounds like a great way to further mess up an emergency by making it harder for people to figure out the impacts of their actions on the situation.

Re: What really happened aboard Air France 447

#177

Post by aperiodic »

Simon_M wrote: post #158
nikcub wrote: post #110

Earlier quoted context omitted.

the other similar incidents are Birgenair Flight 301, where the pitot tubes were blocked because of insect nests, resulting in pilot confusion: http://en.wikipedia.org/wiki/Birgenair_Flight_301 and Aeroperu Flight 603, where the pitot tubes had been covered by maintenance workers and not removed prior to takeoff, also resulting in pilot confusion and lack of confidence in instrument readings: http://en.wikipedia.org/…

Considering how many incidents there seems to be due to the loss of these airspeed sensors it seems crazy not to have an additional, different method of calculating airspeed. Is there a reason GPS is not suitable here?

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

Re: What really happened aboard Air France 447

#178

Post by gnaffle »

nodesocket wrote: post #94
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 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.

At least one of them realized it, but not the one flying. From http://www.bea.aero/en/enquetes/flight.af.447/transcript29ju... :

"At 2h10.16 seconds, the pilot in the left seat, the pilot not flying, says “we have lost the speeds” then “alternate law”"

Re: What really happened aboard Air France 447

#179

Post by mtts »

sek wrote: post #163

One question: Why are they not speaking English? I heard from fatal command mistakes with pilots an Asian country and now everyone has to speak English. Is this again some stupid patriotism thing (i am German, i know the French attitudes), but i seriously thought to prevent command errors everyone has to speak the international aviation language.

In this case, that would probably have made it worse. I doubt a panicked Frenchman would unfreeze just because he has to speak English to another Frenchman.

Re: What really happened aboard Air France 447

#180

Post by ojosilva »

Nick_C wrote: post #120
teyc wrote: post #102

The state of UX design has advanced so much, perhaps we need more UX testing so that even pilots who are unfamiliar with a plane could figure out what to do. Amazon probably does more with figuring how to help users checkout their shopping cart than plane designers helping pilots get a plane out of a stall. Alternate law and normal law introduces two modes. This breaks one of the rules of user experience, especially…

> how does a plane know it's stalling if the pitot tubes are frozen Angle of attack sensor. AoA is the actual definition of a stall as it measures the point at which airflow breaks away from the wing, reducing lift. Re your other points on computer warnings, cockpits can get pretty noisy when shit happens with various alarms, buzzers, horns and voices going off. There's actually a tendency to reduce the number of dif…

I utterly agree on reducing continuous and loud sound warnings in the cabin.

This 1996 757 Aeroperu crash recording is quite scary: http://www.youtube.com/watch?v=G5QSBlYTJ1Y

They had no functioning pitot tubes and lots of contradictory indications, which triggered a storm of alarms, most of them false. Pilots spend quite some time trying to shut alarms off while trying to figure out their situation with air control. I can't imagine trying to talk and cooperate with colleagues, facing a complex system and a life-or-death situation, while so many loud and stressful sounds are buzzing through my ears.

After 9:00, the plane inverts upside down, a "whoop-whoop" alarm goes off and the plane finally crashes into the sea. The alarm only served the sinister purpose of announcing they were going to die.

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