A compressor variable stator vane arrangement comprises at least one stage of variable stator vanes. A speed sensor measures the rotational speed of the compressor rotor. A pressure sensor measures the outlet pressure of the compressor. A second pressure sensor, a temperature sensor and a third pressure sensor measure the total inlet pressure, the temperature and the ambient pressure at the inlet of the gas turbine engine. A processor determines a target operating line as a function of ambient pressure and total inlet pressure. The target operating line is defined to ensure the gas turbine engine operates simultaneously at both the minimum required compressor speed and the minimum required compressor outlet pressure when commanded to idle to minimize idle thrust and fuel burn. The processor determines if the operating point of the compressor, defined in terms of corrected outlet pressure and corrected rotational speed of the compressor rotor is above or below the target operating line of the compressor. The processor adjusts the angle of the variable stator vanes to make the operating point operate on the target operating line.