US Patent 7603242 Fuel leak estimator

A method of detecting a fuel leak from a fuel store of an aircraft where a processor receives inputs relating to the amount of fuel in the fuel store and to the rate of fuel used by the aircraft. The processor defines a fuel flow system state defined by a noise-compensated measures of the amount of fuel in the fuel store, a fuel leak amount estimate and a fuel leak rate estimate. The processor periodically calculates a new estimated state of the system in view of a previous estimated state and values of the inputs. The processor monitors the fuel leak amount estimate and the fuel leak rate estimate and if either exceeds a respective threshold value send a signal to a fuel leak warning device.