The article justifies the need for diagnostics in the maintenance of gas turbine engines in power systems of vessels for production, handling and storage (FPSO type – Floating Production, Storage and Off-loading). It also presents basic features and specifications of turbine engines used on these units as well as methods of obtaining diagnostic information in the maintenance of turbine engines. Parameters of diagnostic signal models (heat-flow, vibroacoustic and exhaust emissions) and methods of their measurement have been identified. Methods of application of on- and off-line data for maintenance purposes have been diversifie