Abstract: A gas turbine engine is provided with a booster stage which operates to increase the power and improve the performance of the engine as well as a particle separator provided at the engine inlet. The booster stage may also eliminate the need for additional anti-icing downstream thereof. The booster is driven at near constant speed by the power turbine of the engine and airflow from the booster is matched to the airflow requirements of the engine by a plurality of variable inlet guide vanes in cooperation with variable bleed means in a manner which maintains the minimum temperature increase of the airflow through the booster required to inhibit ice formation downstream of the booster. In addition, the booster operates to improve the centrifuging effect of the inlet separator, thus eliminating the need for a separate blower for extracting extraneous matter from the collection chamber of the separator.