Abstract: Air captured from the tips of a compressor of a gas turbine engine is diverted from the engine core and can be collected for auxiliary uses. Gas path separation can be achieved using part-span shrouded compressor blades or using blade tip cut-outs conforming to an airflow dividing annular shroud. In a preferred application for the present invention, the gas turbine engine is the auxiliary power unit of an aircraft. This permits compressed air generation for Auxiliary Power Unit oil cooling and for compartment pressurization without loosing significant mass flow to the engine core, while eliminating the need to provide a separate active cooling system such as an engine driven fan.