Patent ID: 8483902

Claim:
Method for calculating oil consumption and range associated with a lubrication system of an airplane engine during flights, the airplane including a plurality of engines, based on a measurement of an oil level in a tank of said lubrication system, allowing management of refills and maintenance and detection of either abnormal consumption or insufficiency range, characterised by a combination of the following methods: comparing with a processor different engines of the airplane and possibly a reference value, the engines used for said comparison being in more or less identical condition, in order to detect abnormal oil consumption; taking into account with a processor one or more interference effects that affect said oil level in the tank, these being linked at least to the thermal expansion in the tank, to gulping and to attitude and acceleration, in order to deduce a modification to the oil level due to a decrease in total quantity of oil available as a result of said interference effects; and wherein, for a measurement and detection when the airplane is landed or during flights: oil levels are measured several times during each phase and during the transitories; an average gulping is estimated depending on an oil temperature and on rotation speed, including in flight during transitories; a range value is deduced from there and is specific to future flights; and characterised by the following sub-stages: a current oil level is measured in the oil tank of one of the engines; said interference effects are estimated, including gulping; a value of the quantity of oil available is calculated by subtracting from the a priori known total quantity of oil a difference in oil quantity associated with a quantity retained outside the tank as a result of these interference effects, linked in particular to gulping; if the value of the available quantity is lower than a predetermined threshold value, a low oil level alarm is emitted and a range value in hours is communicated; based on the total quantity of oil, a current and an average oil consumption of the engine are calculated over the flight phase in progress or over a rolling period during the flight phase in progress, a length of which is fixed by a required accuracy; the current consumption value is used in a comparison and range estimation unit whereas the average consumption value is recorded and processed a processing unit called a long term processor in which thresholds of normal consumption resulting from measurements and calculations from previous flights are re-evaluated in particular in view of this average consumption value, of a total flight time of the engine and of a number of maintenance sessions performed.