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.
What really happened aboard Air France 447
161–170 of 374 posts
Re: What really happened aboard Air France 447
#162Co-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…
- Delineate command better, e.g. Captain, Co-pilot #1, Co-pilot #2 so that who is in charge is clear. This antiquated idea has killed many more people than it would have saved in this case. Read about CRM: http://en.wikipedia.org/wiki/Crew_resource_management I think a classic example is: http://en.wikipedia.org/wiki/Avianca_Flight_52 The plane crashed because it burned all of its fuel in a holding pattern waiting to…
Deliberate selection of inputs would be best. Maybe a switch in the middle that both selects and displays which input is active?
Re: What really happened aboard Air France 447
#163One 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.
Re: What really happened aboard Air France 447
#164Earlier quoted context omitted.
Your link doesn't say that there isn't a clear chain of command, it says that there should be a culture that allows professional disagreement or calling to attention. Just because the captain is declared top dog doesn't mean that protocol demands subordinates must remain quiet.
Yes, the link doesn't say that, but research further and you'll find that the concept of a hierarchy is what CRM aims to eliminate. It's the First Officer's job to take the flight controls from the captain if the FO thinks the captain is doing something dangerous. Not to ask for permission, but to immediately do . This goes against the concept of a hierarchy, but is why they put two sets of controls up there.
I think you'd still do better to have a manual selection of which input is commanding, with an option of having both sticks linked and moving together.
Re: What really happened aboard Air France 447
#165Earlier 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…
Bonin would have had to realize that the plane is in alternate mode in the first place in order to react correctly. It probably never crossed his mind since he never trained in it, and conversely if he had trained in it, he may have been more likely to at least check.
But to me the bigger problem seems to be that such an important change in the plane's behaviour could happen without anyone noticing. I'd consider the mode to be something the pilot must be made aware of, not something he has to deduce from the fact that the airspeed isn't available.
Perhaps the mode is shown prominently and the pilots just didn't notice it in their state of panic. Making it more prominent probably leads right into an insane arms race - the stall warning was as prominent as anything can be and still got ignored.
I don't envy the person who has to design a airliner cockpit's user interface and decide which of a hundred potentially vital pieces of information should be displayed how.
Re: What really happened aboard Air France 447
#166Earlier quoted context omitted.
- Delineate command better, e.g. Captain, Co-pilot #1, Co-pilot #2 so that who is in charge is clear. This antiquated idea has killed many more people than it would have saved in this case. Read about CRM: http://en.wikipedia.org/wiki/Crew_resource_management I think a classic example is: http://en.wikipedia.org/wiki/Avianca_Flight_52 The plane crashed because it burned all of its fuel in a holding pattern waiting to…
Your link doesn't say that there isn't a clear chain of command, it says that there should be a culture that allows professional disagreement or calling to attention. Just because the captain is declared top dog doesn't mean that protocol demands subordinates must remain quiet.
BTW, who is commanding the plane (by inputs) and who is commanding the crew are entirely separate questions. I think one of the serious issues that MUST be addressed here is the issue of conflicting commands to the plane.
Two options.... 1) Place all controls between the pilots so they can easily see what eachother is doing or 2) Place a selection switch and indicator that allows a pilot to unambiguously take control of the plane and disable the other input, or to keep them in linked mode where they move together and provide tactile feedback as to what the other input is doing.
Re: What really happened aboard Air France 447
#167Earlier quoted context omitted.
From what I read from the preliminary report, it's established that the stall warning sounded. If it had not been audible on the CVR, they would probably have noted it. One problem was that the stall warning stopped due to high angle of attack even though the plane was stalled, and it started again when the nose was lowered and the AOA was in the "valid" region again. This might have confused the pilots in a situatio…
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 not certified for stalls, you can't really practice full stalls and have to train on approach to stalls instead.)
Re: What really happened aboard Air France 447
#168Earlier 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.
Make it a loud, repeated aural indication. Oh wait, the stall warning was just that and got completely ignored...
I think we've discovered the most difficult UX design task on earth.
Re: What really happened aboard Air France 447
#169I hope the analysis of the flight was more accurate than some of the translations.
02:08:03 (Robert) Tu peux éventuellement le tirer un peu à gauche. You can eventually pull it a little to the left.
Eventuellement is not the French equivalent of the English. It should be "You could pull a little to the left." Many sentences read like a straight copy and paste from Google Translate.
Re: What really happened aboard Air France 447
#170Earlier 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 can only tell you how fast you're moving over the ground. It can't tell you how fast you're moving through an airmass that might be moving with or against you, this is far more important to keeping a plane in the air than how fast you're moving between point a and point b.