Scavenge pump system and method

A scavenge pump system for scavenging oil from a plurality of bearing chambers of a gas turbine engine, the gas turbine engine having:

• a compressor;
• and a turbine driven by hot gas from a combustor, mounted on at least one shaft mounted for rotation about an axis on a plurality of bearings housed in said bearing chambers, the gas turbine engine including an oil supply circuit having a pressurized oil supply conduit to each bearing chamber and an oil scavenge circuit from each bearing chamber, the scavenge pump system comprising:
• a turbine having an inlet and an outlet each in flow communication with the pressurized oil supply circuit, the turbine being powered to rotate on a turbine shaft in response to pressurized oil flow over the turbine and extracting motive power from the flow of oil through the pressurized oil circuit;
• and a scavenge pump having an inlet and an outlet each in flow communication with the scavenge oil circuit, the scavenge pump being mechanically connected to and powered by the turbine shaft.