Ufa Engine Industrial Association and NPO Saturn Research and Production Association are carrying out a comprehensive modernization of AL-31F aero-engines. Their experimental models (117S Prototypes) are currently being flight-tested.
117S engines are mounted on Su-35 aircraft. After certain updating of engine nacelles and control systems, they may power Su-27 and Su-30 aircraft.
117S engines are substantially modified AL-31F production engines employing fifth-generation technologies. They use a new fan, new high and low pressure turbines, and a new digital control system. A provision is a made for using a vectored thrust nozzle. The modernization has increased the engine special mode thrust by 16%, up to 14,500 kgf. In the maximum burner-free mode it reaches 8,800 kgf.