6 ms·

I'm sure there are plenty of compensation lawyers, and even pilots, who will agree with you. But from a safety perspective "wilful pilot negligence" simply isn'

by Pitarou 13y ago

I'm sure there are plenty of compensation lawyers, and even pilots, who will agree with you. But from a safety perspective "wilful pilot negligence" simply isn't good enough. In this situation, there just wasn't room for negligence to slip in. If we blame the pilot, we'll miss something important. A wilfully negligent pilot would be unlikely to get through training. And even if he was sloppy, it's hard to imagine somebody being so negligent that he didn't bother to check his airspeed when landing a 777 under the watchful eye of his instructor. And why didn't the instructor intervene? Something else is going on. And, yes, if I was a gambling man, I'd put money on the Airbus explanation. I've spoken to Boeing pilots who describe the experience of flying with an Airbus as "creepy" and "eerie". To me, that's a hint that something interesting is happening. I suspect that, by removing certain kinds of feedback, the experience of flying an Airbus is rewiring pilots' brains in dangerous ways. If I'm right, when we finally get to the bottom of what's going on, we'll learn something important about human cognition and response. This will have important implications for the design of safety critical systems. This time, it was easy for me to make the case against pilot negligence. It's rarely so clear-cut, and it's normal for people to want to blame the pilot. None more so than the pilots themselves, who love to say, "That couldn't happen to me. I wouldn't make that dumb mistake." This is why the "no-blame culture" is so important in aircraft and medical accident investigations. If we insist on pointing the finger at the human involved, we never learn.

mikeash 13y ago
The pilot in question has out and out stated that he was uncomfortable performing visual approaches. Now, while it does indeed boggle the mind as to how such a person could get through training and attain command of a 777, the fact is that he did so. I don't see how you can argue against negligence when the pilot has basically come out and admitted it (although he doesn't seem to think he has).
pg 13y ago
"I suspect that, by removing certain kinds of feedback, the experience of flying an Airbus is rewiring pilots' brains in dangerous ways." I don't know whether that's true or not, but that seems something it might be possible for an aircraft design to do, and if so, something to avoid. Does anyone know to what if any extent aircraft designers try to avoid letting pilots become too detached from the experience of flying?
- WalterBright 13y ago
  I worked on 757 flight controls design back in the early 1980's. I'm not a pilot and I'm not familiar with the Airbus designs. The 757 flight controls were hydraulically operated, and were controlled by cables operated by the pilot that opened valves on the actuators (hydraulic rams) on the control surfaces. The pilot's controls did not directly feel the flow of air over the control surfaces feeding back into the stick, like a light plane would with the cables moving the control surfaces directly. To correct this, Boeing designed a "feel computer" that would push back on the controls as if actual wind were pushing on the controls. The idea was that as close as possible the pilot's controls should "feel" like he was directly connected to the control surfaces. The feel forces generated could be well over a hundred pounds, if I recall correctly, though Boeing had to reduce them in order to accommodate female pilots. Note that for a high performance aerobatic plane with direct controls, it is a physically exhausting task to control it. My father flew B-17's, which were probably the biggest airplanes without hydraulically assisted controls. You had to be a strong man to fly it. It would fly with only one outboard engine running, but the force required on the rudder pedals meant the pilot and copilot had to constantly relieve each other.
  - hatbert 13y ago
    There were actually bigger planes, like the Martin JRM Mars (a large WWII flying boat) with a gross takeoff weight in excess of 165,000 lbs. They use a mechanism called a "servo tab," which is sort of like a control surface for the control surface. In essence, it deflects in the opposite direction of the control surface, and usually in proportion to the control force (a system of levers and springs measures the amount of force being transmitted to the controls by the surface). The primary disadvantage, aside from the complexity of the system, is that it tends to delay feedback, which results in PIO.
- Pitarou 13y ago
  I don't mean that kind of feedback. I mean the feedback you get that teaches you to the limit of the vehicle's operational parameters. For instance, when I started driving, I sometimes used the brakes too aggressively, and experienced a number of "micro-skids". These experiences quickly taught me how hard I could get away with pushing my vehicle. But it's not something I'm consciously aware of: my foot just automatically reaches for the brake pedal at the right moment. There's a subconscious "anti-skid system" built into my brain. And that's the way it has to be. I couldn't possibly maintain conscious awareness of all aspects of vehicle operation. I'm not that smart! The Airbus control scheme takes that feedback away. Pilots don't directly control the plane at all. They merely tell the plane what they want it to do, and the plane's control system decides whether it's a good idea or not. If a pilot does something that would stall the plane, the plane just doesn't respond. I suspect that this causes the Asiana 214 pilot's subconscious "anti-stall system" to atrophy, to the point where he was no longer competent to manage a Boeing plane. The bit of his brain that automatically monitored flight speed and the red pips was no longer functioning. More seriously, his higher faculties were not aware that his subconscious systems could no longer be trusted (beyond a vague sense of unease). Well, that's my theory, but note that I haven't explained why the instructor didn't spot what was going on.
tga 13y ago
You may be onto something there, but this explanation doesn't cover the instructor, who was experienced on Boeing, not Airbus.
the_watcher 13y ago
This reminds me of something (much less substantive and important) that I have been realizing after buying my first Apple computer recently (I held out for a long time). Things like the trackpad and cable wrapping system are so amazingly intuitive, once you figure them out. However, I am so accustomed to sub optimal design, that I had to be shown how to use them both. This may be a case where sub optimal design is a net win, but ensuring that the pilots must stay engaged to at least a minimal degree.

by Pitarou 13y ago

mikeash 13y ago

The pilot in question has out and out stated that he was uncomfortable performing visual approaches. Now, while it does indeed boggle the mind as to how such a person could get through training and attain command of a 777, the fact is that he did so. I don't see how you can argue against negligence when the pilot has basically come out and admitted it (although he doesn't seem to think he has).

pg 13y ago

"I suspect that, by removing certain kinds of feedback, the experience of flying an Airbus is rewiring pilots' brains in dangerous ways." I don't know whether that's true or not, but that seems something it might be possible for an aircraft design to do, and if so, something to avoid. Does anyone know to what if any extent aircraft designers try to avoid letting pilots become too detached from the experience of flying?

WalterBright 13y ago
I worked on 757 flight controls design back in the early 1980's. I'm not a pilot and I'm not familiar with the Airbus designs. The 757 flight controls were hydraulically operated, and were controlled by cables operated by the pilot that opened valves on the actuators (hydraulic rams) on the control surfaces. The pilot's controls did not directly feel the flow of air over the control surfaces feeding back into the stick, like a light plane would with the cables moving the control surfaces directly. To correct this, Boeing designed a "feel computer" that would push back on the controls as if actual wind were pushing on the controls. The idea was that as close as possible the pilot's controls should "feel" like he was directly connected to the control surfaces. The feel forces generated could be well over a hundred pounds, if I recall correctly, though Boeing had to reduce them in order to accommodate female pilots. Note that for a high performance aerobatic plane with direct controls, it is a physically exhausting task to control it. My father flew B-17's, which were probably the biggest airplanes without hydraulically assisted controls. You had to be a strong man to fly it. It would fly with only one outboard engine running, but the force required on the rudder pedals meant the pilot and copilot had to constantly relieve each other.
- hatbert 13y ago
  There were actually bigger planes, like the Martin JRM Mars (a large WWII flying boat) with a gross takeoff weight in excess of 165,000 lbs. They use a mechanism called a "servo tab," which is sort of like a control surface for the control surface. In essence, it deflects in the opposite direction of the control surface, and usually in proportion to the control force (a system of levers and springs measures the amount of force being transmitted to the controls by the surface). The primary disadvantage, aside from the complexity of the system, is that it tends to delay feedback, which results in PIO.
Pitarou 13y ago
I don't mean that kind of feedback. I mean the feedback you get that teaches you to the limit of the vehicle's operational parameters. For instance, when I started driving, I sometimes used the brakes too aggressively, and experienced a number of "micro-skids". These experiences quickly taught me how hard I could get away with pushing my vehicle. But it's not something I'm consciously aware of: my foot just automatically reaches for the brake pedal at the right moment. There's a subconscious "anti-skid system" built into my brain. And that's the way it has to be. I couldn't possibly maintain conscious awareness of all aspects of vehicle operation. I'm not that smart! The Airbus control scheme takes that feedback away. Pilots don't directly control the plane at all. They merely tell the plane what they want it to do, and the plane's control system decides whether it's a good idea or not. If a pilot does something that would stall the plane, the plane just doesn't respond. I suspect that this causes the Asiana 214 pilot's subconscious "anti-stall system" to atrophy, to the point where he was no longer competent to manage a Boeing plane. The bit of his brain that automatically monitored flight speed and the red pips was no longer functioning. More seriously, his higher faculties were not aware that his subconscious systems could no longer be trusted (beyond a vague sense of unease). Well, that's my theory, but note that I haven't explained why the instructor didn't spot what was going on.

tga 13y ago

You may be onto something there, but this explanation doesn't cover the instructor, who was experienced on Boeing, not Airbus.

the_watcher 13y ago

This reminds me of something (much less substantive and important) that I have been realizing after buying my first Apple computer recently (I held out for a long time). Things like the trackpad and cable wrapping system are so amazingly intuitive, once you figure them out. However, I am so accustomed to sub optimal design, that I had to be shown how to use them both. This may be a case where sub optimal design is a net win, but ensuring that the pilots must stay engaged to at least a minimal degree.