I really don't like the tone that so many post-accident discussions take regarding automation, Boeing v. Airbus, etc. -- when the plain facts of the incidents (specifically this, and Air France 447) boil down to one small, really important bit willful negligence.
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.
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?
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.
The primary disadvantage, aside from the complexity of the system, is that it tends to delay feedback, which results in PIO.
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.
In this accident, I think the main problem was not anything Boeing vs Airbus, but more a lack of experience with hands-on flying visual approaches, and a lack of monitoring, which would quickly have uncovered the fact that the auto-throttle wasn't operating. If the linked PPRune posting has any truth in it, I think we a have a substantial part of the explanation there.
Prof. Missy Cummings (former F/A-18 pilot) at MIT is involved in research into cockpit automation. She was featured on at least one documentary into AF447.
What is interesting in the Airbus vs Boeing debate is that pilots like Capt. Sullenberger who has flown both Boeing 737s and Airbus A320s doesn't claim its an "Airbus" problem. The problem is that airline pilots are becoming overly reliant on autopilots and forgetting the basic skills of flying the aircraft. http://www.cbsnews.com/news/capt-sully-sullenberger-airplane...
Completely agree. Unfortunately, the vasty majority of aircraft incidents occur because of pilot error. People can and will make mistakes. We need to accept that or automate more. I'm in the automate more camp.
In that case, however, you could point to a big UX problem: It was not announced in big, red letters that the fly-by-wire system had in fact been deactivated. If I remember correctly, this was hidden under some menu in the flight computer and simply abstracted away to a "master caution" light or something in that vein.
Sum them?
Only take the most extreme of the two inputs (in any given direction)?
Only take the most recently seen input?
Averaging makes more sense than any of those, given the premise of "Control sticks that can move in different directions"
It was announced in medium-sized orange letters reading “F/CTL ALTN LAW (PROT LOST)”. At least one pilot did notice this; the co-pilot who wasn’t pulling up the whole time said “alternate law, protections lost” out loud, as recorded on the CVR, when the message appeared.
I think there was a similar problems at Qantas Flight 32, where the crew had to spend a lot of time going through 54 error messages after an uncontained engine failure.
Not paying attention to your airspeed is the sort of mistake you should be able to eradicate.
I want to know why a pilot who says that he is "very concerned" with doing a simple visual approach is allowed to have a couple hundred lives in his hands in an airliner. This is Piloting 101.
Mistakes are inevitable, but we shouldn't just throw up our hands either, especially when this particular mistake comes down to straight-out incompetence and a pilot who's afraid of a basic and straightforward flight operation.
Would you feel better if he said he was "not concerned at all" with landing the airplane?
> [The pilot] "stated it was very difficult to perform a visual approach with a heavy airplane."
From http://www.cbsnews.com/news/ntsb-asiana-crash-pilot-very-con...
This is, of course, complete bullshit.
From the same article:
> Lee said he told his instructors about his concerns in the flight's planning stages. He told investigators that as he realized his approach was off, he was worried he might "fail his flight and would be embarrassed."
More:
> Since “everyone else had been doing the visual approach … he could not say he could not do the visual approach,” according to NTSB
From http://atwonline.com/safety/asiana-777-pilot-sfo-visual-appr...
Would I feel better if he said he was "not concerned at all"? Of course I would. He was performing an easy landing in completely benign weather at an airport with nothing at all tricky or unusual about its approach. There was no reason whatsoever to be concerned.
I'm not a pilot but I am a technical diver, and we eschew many of the conveniences that recreational divers use, such as relying on dive computers. We work out dive plans on paper, and backup plans, and carry them with us on a slate. The only instruments we rely on are watch, depth gauge and compass, and these are of the simplest possible design, and we have backups for them. If something happens on a deep dive or a cave dive, you know exactly what the state of your system is and can reason about it. Not so if you were used to something else tracking it for you, and you had to start discovering it from scratch.