System and method for monitoring lubricant of an engine

A method for evaluating performance of an engine, comprising:

• obtaining flight-phase lubricant quantity monitoring messages and lubricant addition messages of the engine in multiple consecutive legs according to lubricant quantity of the engine collected in the multiple consecutive legs, wherein the lubricant addition messages comprise information reflecting whether lubricant is added during a flight stop phase and quantity of the lubricant added during the flight stop, and wherein the quantity of lubricant added are automatically determined according to the lubricant quantity of the engine collected by the data acquisition unit during the flight stop phase;
• calculating lubricant consumption of each leg within the multiple legs;
• obtaining changing rule of lubricant consumption within the multiple legs;
• comparing the resulted changing rule of the lubricant consumption with the changing rule of lubricant consumption obtained when the engine works in a good state;
• and
• in response to result of the comparison, evaluating performance of the engine.