101–110 of 374 posts
What really intrigues me is the fact that the captain didn't take control of the plane after returning from his nap. If a respected pilot with 11,000 flying hours to his credit made that mistake, I can't imagine what his mind must have gone through during that time.
Alternate law and normal law introduces two modes. This breaks one of the rules of user experience, especially if it is infrequently encountered. Combined with turning autopilot off on its own, it is bound to cause even more confusion. The plane could have put an alert asking the pilot to go on autopilot, otherwise, it will continue by making educated guesses. (A pilot is no better judge of airspeed than the computer)
Another rule of UX broken is "tell" instead of "announce". The voice should have said "Stall. Dive now" or "Stall. Why are you pulling the stick back?".
The flight computer can reinforce its credibility by demonstrating it has predictive capability. For instance, it can say, "decrease your angle of attack or you will stall in 5 seconds", then "4", "3" "2" "1", "stalling". The voice should demonstrate increased tension and panic as counting down.
It is high time the flight computer act as the "third pilot". It is similar to video judges in competitive sports. Of course people may choose to ignore the computer, but we can then continually review why the computers assessment was wrong and improve on it.
What I don't understand is, how does a plane know it's stalling if the pitot tubes are frozen?
By the way, optical flow meters could have been used as a backup.
That was a chilling read.
Absolutely. You can almost feel the panic they must have experienced, trying to comprehend what was happening, in the dead of night, over the ocean: "What the hell is happening? I don't understand what's happening." "Damn it, I don't have control of the plane, I don't have control of the plane at all!" It's like a non-fiction horror story. Cockpit data recorders provide some really gripping stories. Same with the air…
Having multiple joysticks that can be in different positions at the same time and yet all simultaneously affect the flight of the Airbus is a serious design flaw.
Earlier quoted context omitted.
It's hard to measure how fast you're going through the air without being able to sample the air. Pitot tubes are just the tubes that bring the air to the inside of the plane to be sampled; nothing more.
I mean, I know the physics behind pitot tubes, but I wonder if we'll come up with a better way of measuring this. Something like measuring deflections of a thousand tiny rods on the plane skin. Still vulnerable to icing and other mechanical damage, I suppose. Maybe we'll just have really accurate GPS and beam external local instantaneous wind-speed measurements to the plane.
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…
I think the simplest solution to the mismatched stick issue is to use servo motors to replicate the old situation--the movement of each stick mirrors the movements of the other. A pilot wouldn't have to look for some stick position display, or indicator light, if they can easily feel the deflection of the stick.
Earlier quoted context omitted.
So, here's the problem with this whole normal law / alternate law situation: If a pilot believes he is in normal law, and wants to ascend above the storm, he'll probably just pull all the way back on the stick, thinking "this will cause the computer to ascend as quickly as it can without stalling". AAAARGGHH!!!! This maddening concept of normal law is turning the above insanity into the EXPECTED OUTCOME! Having a com…
This is an important point as cars nowadays have more and more electronic overrides - everything from traction control to stability control to anti-lock brakes to lane departure warnings (and recovery) to emergency braking and speed control. Most of the later ones (emergency braking, speed control, lane departure) are only on expensvie cars, but within 10 years will be standard equipment on all cars. If not by legisl…
What a sobering article.
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…
- Add a display that shows the current positions of both control sticks. Add an alarm when the two sticks are not within a certain margin of the each other, if both are engaged. Such as if one is full forward & the other is full back. This was my first thought as well. Confusion in one pilot was allowed to cause confusion in the second pilot, because he didn't realize that his partner was doing something unexpected a…
Earlier quoted context omitted.
You suggest that one problem might be that Bonin didn't know his angle of attack. Alternately, I remember a similarity here with an Egypt Air flight that went down when some instruments went dead: when one of the instruments experienced malfunction, the pilots suddenly found it hard to believe anything the computer was saying. So maybe, on some level, Bonin dismissed the stall warning because the speed sensor had fai…
The NTSB concluded that 990 was a homicide. A relief pilot assumed control after take-off and then deliberately crashed the aircraft. From what I hear, it wasn't a fun week at the RI Medical Examiner's office.
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/wiki/Aeroper%C3%BA_Flight_603
With these similar incidents you would think that air crews would have learnt from these disasters. If you read the reports on those two accidents, the similarities to the AF disaster are remarkable.