The aircrew escape propulsion system is composed of a variety of propellant actuated devices that when sequentially activated provide for aircrew safety during an emergency egress. Units such as catapults or the catapult phase of a rocket catapult will propel the ejection seat and its occupant out of the aircraft. Units such as under seat or seat back rocket motors or the rocket phase of a rocket catapult will propel the ejection seat and occupant safely away from the aircraft. Other rocket motors provide reactive impulse for seat subsystems such as man-seat separation, seat trajectory modification, canopy jettison, or parachute deployment. The system will propel the occupant of the seat at a sufficient velocity to ensure that he will clear a fast moving aircraft by a safe margin and attain a height required to permit parachute deployment and a normal and safe descent. The specific intended use for a particular unit will be described in 6.1 of the individual associated detail specification.