Operation (NACES/FAST)

The TESP Electronic Sequencer operates as follows:

• When ejection is initiated, the thermal batteries are initiated by gas pressure generated when the ejection handle is pulled. The battery output rises very quickly to a usable level, activating all the Sequencer electronics within 130ms.

• The ejected seat travels up the rails and triggers the Sequencer start switch, providing the turn-on pulse, which becomes time zero (To) for Sequencer operation.

• Within a few milliseconds of To, the seat mounted pitot and static ports clear the aircraft and measure the dynamic and static pressures. These pressures are measured by the Sequencer's redundant solid-state sensors. Additionally, three axes of acceleration are redundantly sampled and processed as part of the total environmental measurement to determine the optimum recovery mode.

• The environmental data is processed through the analog to digital circuits and MUXed to the triple redundant microprocessor circuits, which solve algorithms to determine the parameters (altitude and velocity) of this ejection.

• These parameters are processed to determine the initial recovery mode. Depending upon the mode selected the sensors may be continuously sampled until an optimum threshold is reached indicating parachute deployment and other associated events. All this processing occurs within milliseconds. The timing of events is accurate to within one millisecond.

• All of the recovery events are timed to within 1 millisecond. The 5 Amp EED initiation signals to the redundant 3.5 Amp all fire MIL-STD-1512 electro-explosive devices (EEDs) are timed to last 10 milliseconds to ensure a successful event firing.