The problem of how to choose the parameters in the aero engine gas path fault diagnosis was studied. Using engine fault diagnosis matrix

a simple and fast algorithm based on eigenvalues and eigenvectors to compare the advantages and disadvantages between different measurement systems was proposed. The algorithm can directly show the change of the global solution space and the direction of vectors from a geometric perspective. A comparison case study of a single-axis turbojet engine test system showed that the maximum-minimum eigenvalue ratio of the ground test system was 33

and the maximum-minimum eigenvalue ratio of the airborne system was 1008. The ground test system is more advantageous to the fault diagnosis of the single-axis turbojet engine than the airborne system.The algorithm can be used to optimize the layout of sensors in airborne engines

measure sensor layout in bench measurement system

and guide the selection of measurement parameters in engineering.