An aeroderivative gas turbine including an air intake plenum; a compressor with a compressor air intake in fluid communication with the air intake plenum; a combustor; a high pressure turbine; a power turbine. A forced air-stream generator is arranged in fluid communication with the air intake plenum. A shutter arrangement is provided in a combustion-air flow path, arranged and controlled to close the combustion-air flow path for pressurizing said air intake plenum by means of the forced air-stream generator to a pressure sufficient to cause pressurized air to flow through the aeroderivative air turbine.