A system and method of monitoring oil consumption in a gas turbine engine system are provided. When the gas turbine engine is not running the reservoir oil level, reservoir oil temperature, and reservoir attitude are sensed. The current gas turbine engine system oil quantity is determined based on at least the sensed reservoir oil level, the sensed reservoir oil temperature, and the sensed reservoir attitude. When a predetermined event has occurred, an average gas turbine engine system oil quantity is automatically calculated. The gas turbine engine system oil consumption rate is determined from a plurality of the average oil quantities.