Alert! The Appearance of Moded Input Devices in the Modern Airliner Cockpit

The automation in the flight deck of a modern airliner has grown in functionality over the past several decades, improving safety and operational efficiency. As the sophistication of automation has increased, some traditional input devices in the cockpit, such as throttle levers, yokes, and switches, have unobtrusively changed the way they work. Instead of operating the same way at all times, the behavior of these input devices has become context-sensitive (i.e., "moded"). It is well known in human factors design that nonsalient moded input devices require increased cognitive workload and can result in a startle, surprise, and confusion. An analysis of modern airliner cockpits identified three types of moded input devices: 1) disabled, 2) alternative behavior, and 3) command override. The implications of these results on cockpit design, certification, and flight crew training are discussed.