Abstract: Analytical redundancy technology based on autoassociative neural network is presented for aeroengine sensors.It doesn't depend on model and needs only the sample net of measurement data without sensor fault to train the network.Then it can work on-line.Estimation Feedback Scheme is developed and can meet the real-time requirements.If there has been performance degeneration of aeroengines,a compensation algorithm can be used automatically.Sensor fault analytical redundancy is accomplished by integrating the network estimation and fault detection logic.The results of theoretical analysis and simulation show that the provided scheme has the ability of distinguishing performance degeneration and sensor faults,and it also can detect soft faults of sensors.