Engineers of the United Engine Corporation (ODK) developed a new fault-tolerant aircraft engine control system that makes it possible to keep it operating even in the event of a complete failure of the digital automation. The invention has already been registered in the database of the Federal Service for Intellectual Property (FIPS).
The development concerns electronic control systems of the FADEC type, which are now used by most modern aircraft engines, including the PS-90A. In the standard configuration, if such a system fails, the pilot is forced to shut down the engine for safety reasons.
Russian engineers proposed a backup solution. An emergency solenoid valve was built into the hydromechanical fuel metering unit, which automatically activates a special engine operating mode.
If the electronic controller fails, the valve will switch the system to a constant fuel flow. It corresponds to the landing idle mode — the minimum thrust sufficient for safe flight and approach for landing.
At the same time, the engine actuators automatically move to safe positions. For example, the compressor variable geometry system closes the guide vane assembly and opens the air bleed valves, which prevents surge and maintains stable operation.
Such a scheme makes it possible not to shut down the engine in flight even in the event of a complete failure of the digital control system. The aircraft retains minimum thrust, and the crew can continue the flight or carry out a safe landing.