Aircraft anti-theft system

摘要

An anti-theft system that can be retrofitted onto existing aircraft disables the starter motor of an engine or engines a predetermined time after the aircraft is taken out of service and re-enables starting only after the pilot has provided adequate identification (e.g. by entering a personal identification number at a cockpit keyboard). The predetermined time interval is selected to be long enough to ensure that the system does not impose a flight hazard by preventing in-flight re-starts. In a preferred version of the system, a drop in the output voltage of the aircraft's main electric power system is used as an indication that the aircraft is out of service. To simplify installation on existing aircraft, the system provides for communication among various functional elements over a pre-existing part of the aircraft (e.g. by imposing AC tones on a starter motor control line).