Persistent and increasingly frequent failures of the Airbus A320’s rudder travel limiter system had occurred for several months. Ultimately, when the normal procedure failed to stem a rash of failures during a flight over Indonesia’s Java Sea on Dec. 28, 2014, the pilot-in-command (PIC) tried a different method — one he had seen a maintenance engineer perform on the ground.
The unexpected consequences — an uncommanded, rapid left roll and disengagement of the autopilot — startled the flight crew. They responded improperly to the upset and lost control of the A320, which descended fully stalled into the sea, with the loss of 162 lives, according to the report by the Indonesian National Transportation Safety Committee (Komite Nasional Keselamatan Transportasi, KNKT).
The rudder travel limiter is part of the electronic flight control (fly-by-wire) system used in most Airbus aircraft. A simple description of the system is that yaw, roll and pitch control signals to and from the…
