Abstract: An overthrust protection system for an aircraft engine. The system comprises an engine overspeed protection unit comprising overspeed logic and an overspeed solenoid valve controlled by the overspeed logic, the overspeed logic configured to energize the overspeed solenoid valve for removing fuel flow to the engine upon detection of an overspeed condition of the aircraft engine; and an overthrust controller coupled to the overspeed protection unit and configured to measure engine thrust and to detect an overthrust condition when an engine thrust threshold has been exceeded, and configured to trigger energizing of the overspeed solenoid valve upon detection of the overthrust condition and an aircraft-on-ground condition.

Abstract: A first and second engine are connected to a drive train for driving an aircraft accessory. A gearbox is connected to a primer mover propulsor and an actuator operatively associated with a selected engine is moveable between a position in which the selected engine drivingly engages the gearbox for driving the propulsor and a position in which the selected engine disengages from the gearbox. A position signal, a status signal, and a request signal respectively indicative of a present position of the actuator, a governing state and present speed of each engine, and a request for movement of the actuator from the present position to the other position are received. If the selected engine's speed differs from a predetermined threshold, a control signal is output for causing the engine's speed to be adjusted towards the threshold. A control signal indicating that movement of the actuator is permitted is then output.