LISS

Special Sensor Technology

The LITEF Seat Sequencer (LISS) is a system for controlling the escape sequence of an ejection seat.

Sensor data based controller

Based on the measurement of flight speed and altitude at the time of an ejection the Sequencer controls the activation timing of multiple emergency systems of the ejection seat.

LISS Details

The LISS Seat Sequencer is a compact system designed with multiple redundancy and is used to control the escape sequence of an ejection seat rescue system. It was developed on behalf of Martin-Baker Aircraft specifically for the MK16A-ejection seat in the Eurofighter.

The seat sequencer is not activated until the pilot pulls the ejection mechanism. When the pilot seat leaves the cockpit, the recording of the current movement data by accelerometer and pitot sensors, as well as the barometric altitude, begins. Depending on these variables, an escape sequence with variable timing is initiated that initially deploys a stabilisation chute, then the main parachute. Finally, the pilot is separated from the seat.

Sensor data gets processed in independent CPUs and is evaluated by a complex software and hardware voting process. This in turn leads to the coordinated activation of the pyrotechnical igniters located in the seat. The activation data are stored in the Seat Sequencer memory for later analysis.