Carbon containing composite materials are widely implemented in different constructions of airspace technique due to their unique physic-mechanical properties. Nowadays, using different algorithms, methods of recognition and classification of defects and drawbacks, that occur during non-destructive control of composites, have been developed. This paper describes two such methods one of which based on signals' form analysis and the other on quantitative indexes of mean square root deviation of noised signals from a test signal. Changes of the gap between the eddy current transformer and the surface of a testing material, casual inclinations of the transformer during scanning form drawback impulses. These are the most essential preventing factors. The obtained results let to make correction of these factors and considerably improve reliability of defectoscopy.