A method for performing maintenance on an engine includes: providing an engine maintenance system including a database system having a database and a database management device: providing a first performance parameter stored in the database and characterizes an engine performance before an engine maintenance procedure; providing a maintenance parameter stored in the database and characterizes a scope of a maintenance measure performed on an engine during an engine maintenance procedure; providing a second performance parameter stored in the database and characterizes the engine performance after the engine maintenance procedure; determining, using the database management device, a functional relationship between the maintenance parameter and the contribution of the maintenance parameter to a difference between the first performance parameter and the second performance parameter; outputting the functional relationship via the engine maintenance system; and performing maintenance on the engine taking the functional relationship into account.