With the advent of computer's technique there has been a rapid growth in the use of microcomputers in all engineering activities. This paper outlines the important role played by a general purpose microcomputer in the analysis of the extremely complex vibration signals of the turbojet engines. The proposed system consists of an FFT analyzer and a 64 k micro computer Basically, through proper interface and specialized software, the micro-computer converts the constant bandwidth spectrum to a constant percentage bandwidth spectrum for overcoming small fluctuations in turbojet engine speed. Direct comparison of any two spectra, and comparison with predefined reference mask may be performed. The results of these comparisons are automatically printed in the fault detection program output. The paper includes practical examples illustrating, in detail , the main benefits of using the micro-computer in this domain. All the vibration spectra presented in this paper are measured on real turbojet engines mounted on the test stand.