The Value of Interface Design

If you can recall, a couple of years ago Air France flight 447 crashed in the Atlantic off the coast of South America. The follow-up investigation is returning a report finally, and the conclusion is a bit grim:

It seems surprising that Airbus has conceived a system preventing one pilot from easily assessing the actions of the colleague beside him. And yet that is how their latest generations of aircraft are designed. The reason is that, for the vast majority of the time, side sticks are superb. “People are aware that they don’t know what is being done on the other side stick, but most of the time the crews fly in full automation; they are not even touching the stick,” says Captain King. “We hand-fly the aeroplane ever less now because automation is reliable and efficient, and because fatigue is an issue. [The side stick] is not an issue that comes up – very rarely does the other pilot’s input cause you concern.”

Boeing has always begged to differ, persisting with conventional controls on its fly-by-wire aircraft, including the new 787 Dreamliner, introduced into service this year. Boeing’s cluttering and old-fashioned levers still have to be pushed and turned like the old mechanical ones, even though they only send electronic impulses to computers. They need to be held in place for a climb or a turn to be accomplished, which some pilots think is archaic and distracting.

The American manufacturer was concerned about side sticks’ lack of visual and physical feedback. Indeed, it is hard to believe AF447 would have fallen from the sky if it had been a Boeing. Had a traditional yoke been installed on Flight AF447, Robert would surely have realised that his junior colleague had the lever pulled back and mostly kept it there. When Dubois returned to the cockpit he would have seen that Bonin was pulling up the nose.

Somewhat scary to think something so seemingly simple could cascade so catastrophically. That’s not to say the entire blame lies with Airbus, but it certainly highlights the message that making things obvious in a complex interface, even if feedback from users contradicts the decision, can pay off in situations not commonly envisaged.

(via df)

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