An aircraft solid state power controller comprises a feed node to be electrically connected to a primary electric power supply; a load node to be electrically connected to at least one electric load; and at least one electric switching device, in particular a solid state switching device, which is arranged between the feed node and the load node. The at least one electric switching device is switchable between an on-state, in which the at least one electric switching device provides a low-resistive electric connection between the feed node and the load node; and an off-state, in which the at least one electric switching device electrically isolates the load node from the feed node. The aircraft solid state power controller further comprises a secondary electric power supply, which is independent from the primary electric power supply, and which is configured for applying a test voltage between the feed node and the load node of the aircraft solid state power controller in order to allow determining the switching state of the at least one electric switching device by detecting a voltage drop between the feed node and the load node of the aircraft solid state power controller.