Removal from the aircraft is by a three part pyrotechnic sequence. A gun catapult provides the initial removal of the seat from the aircraft. This senses the motion and attempts to keep the seat from spinning by automaticly providing a correcting force. Once clear of the aircraft, the pitot - static system on the seat measures the conditions and selects one of three operating modes depending on the conditions present at egress. The main parachute deploys as the seat clears the rails.
Drogue parachute remains undeployed to prevent line tangle.
Drogue parachute deploys as the seat leaves the rails. Main parachute deploys 0.8 to 1.0 seconds after the drogue. Drogue chute is then released to prevent line tangle. Drogue parachute deploys as the seat leaves the rails. The pitot - static system senses the conditions and delays the main parachute until mode 2 conditions are met.