A parachute control system is actuated primarily by drogue parachute drag force. Drag force is used as a proxy for vehicle airspeed. The control system uses altitude and force sensors combined with a chronograph to determine the state of a deployed drogue parachute. It then compares the sensed condition with a condition defined by preset altitude, force, and time values. Once both altitude and drogue parachute drag force are below certain maximum values and within pre-determined time windows, an event trigger signal is generated.