The present invention relates to a method for calculating the oil consumption and autonomy associated with the lubrication system of an airplane engine during flights, preferably a turbine engine, on the basis of the measurement of the oil level in the tank of said lubrication system, allowing to manage the refills and maintenance and to detect either abnormal consumption or insufficient autonomy, characterized by at least one of the following methods: comparing 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 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 the “gulping” and to the attitude and acceleration, in order to deduce the modification to the oil level due to a decrease in the total quantity of oil available as a result of said interference effects; combining both above-mentioned methods.