The establishment of reliable correlations between parameters of damage and a sensor response during automatic NDI is first aim of present paper. Second, and it is main aim, is estimation of efficiency different approaches of the fatigue crack prediction at use of scalar parameters of signal – response. Investigation of ultrasonic Lamb wave interaction with a fatigue crack has been executed on flat samples from an aluminium alloy 2024-T3 by thickness 1mm. Three parameters of response were selected for their efficiency comparison. Standard deviation of a predicted fatigue crack was used for comparison. Quite definitely it is possible to conclude, that the given technology of NDT over use of ultrasonic waves is quite capable to provide high stability and necessary accuracy at the continuous integrated SHM of thin-walled aluminum components of aircraft. Result of this research shows that multi-parametric criterion can be used. It is shown also the accuracy of damage predicting is one of the most significant parameter of SHM efficiency. It can be used as the main criterion at selection of diagnostic parameters for continuous integrated monitoring of structural elements of aircraft.