Jet Engines – Bearings, Seals and Oil Consumption

Purpose of this review is to understand how to find values for three input parameters for the calculation of the oil concentration in aircraft cabins. These are the number of bearings of the jet engine and the number of them upstream of the bleed air ports as well as the oil consumption per hour. --- Methodology is an Internet review of related facts. --- Findings: Jet engine schematics are available online and can be interpreted to find the number of bearings. Values for the CFM56 engine are 5 bearings with 3 of them upstream of the bleed port. Oil consumption should be assumed to be 0.3 L/h for the CFM56 engine. Rates for selected other engines are also given. --- Research limitations are due to the fact that detailed company data is not available and own measurements can not be made on passenger jets.