A device for severing an extraction line connected between a cargo load and an extraction parachute when the cargo load fails to eject from an aircraft. The device comprises a cutter spaced from and spring-biased in the direction of the extraction line; a housing for the cutter; elements for mechanically restricting the cutter from engaging and severing the extraction line; and elements responsive to a radio signal from a transmitter on the aircraft for disabling the restricting means so that the cutter is released and severs the extraction line.