This subject fascinates me and I look forward to reading Harford’s book. But the AF447 story has another important aspect beyond the automated avionics: physical design.
Unlike the old manual control yoke (i.e. the aircraft’s ‘steering wheel’) for each pilot that are physically connected, the Airbus has joysticks, one alongside each pilot. They are completely independent and neither pilot can feel what maneuver the other is attempting, as one would on a linked yoke. In this incident, that turned out to play a significant role in the deadly cascade of errors.
When one pilot is pulling back (directing ‘climb’), and the other pushing forward (directing ‘descend’) as happened in AF447, the flight computer, getting inconsistent inputs, cancelled each out without either pilot being aware of the other’s action. This design feature, which compounded pilot error, figured prominently in the catastrophe.
To read a very thorough account of AF447 see this Popular Mechanics article.
Great choice of the photo from ‘Airplane’ by the way.
