pic: Google Streetview driver autograph

[Tristan Lall]

Originally Posted by JesseK

The pilots weren't in sync with each other, as demonstrated at the 02:13:40 mark here. The AirFrance 447 was used as a mere example of the exact complexities you're talking about. I don't think I 'grossly simplified' it.

The issue at hand in a car isn't whether 2 drivers need to be in sync or whether steer-by-wire is 'safe', 'important', or 'whatever'. It's a fundamental tendency for humans to stop paying attention to the dynamic, constantly-changing situation the vehicle is put into since 'autonomous' can do it 'better'. The Airbus situation, where the pilots had to take over in an emergency, is easily multiplied on the road because there are astronomically more interactions for a computer to be unable to handle while driving.

I think Ian was getting at the fact that the AF447 situation wasn't a failure of the automation itself, it was a failure to understand how the aircraft would behave with the automation in "alternate law" mode. In "normal law", which is how the majority of the pilots' training was conducted, a reasonable procedure for an emergency climb is to pull straight back on the stick, and engage maximum power (takeoff/go-around throttle settings, known as TOGA). Instead, due to pitot icing (i.e. neither the pilots nor the automation were able to get accurate airspeed indications), the system defaulted to alternate law, a more manual mode, and the pilots didn't respond correctly. One pushed forward to gain speed, one pulled back to gain altitude, when in reality they needed both, but needed speed first to avoid stalling, then altitude to avoid crashing. The pilots did not understand the implications of those opposing control inputs.

On a fly-by-wire Boeing, the pilots would have been fighting each other, due to the interconnected yokes, and probably would have realized what was going on. The autopilot would still not have worked, and the pilots would not have had an airspeed reference (due to pitot ice). Therefore the aircraft would not have been able to deliver the stall warning (though it probably would have said something about angle of attack).

In other words, these were conditions that would incapacitate any autopilot, and seriously diminish the ability of any pilot to fly manually. A more correct analogy to make with the Google cars is to wonder whether they would let the cars continue to operate in conditions that were unusually snowy, or with a malfunction in the drivetrain or steering. I think the answer is clearly no. (Of course, a car can pull over and wait; a plane has to land first.)