A variable vane actuation system of a gas turbine engine is provided. The variable vane actuation system including: a variable vane; a vane stem operably associated with the variable vane, wherein the variable vane is configured to rotate with the vane stem; a vane arm having vane stem end and a vane pin end opposite the vane stem end, the vane arm being operably connected to the vane stem at the vane stem end; and a rotational variable differential transformer operably connected to the vane stem, the rotational variable differential transformer configured to detect an amount of rotation of the vane stem.