A method of supporting and performing maintenance on a fleet of aircraft is provided. The method includes generating a computer model that describes a process performed by a system for in-service operation and maintenance of the fleet of aircraft. The method also includes performing a discrete event simulation of the process, via a computer processor configured to access the computer model and generating a maintenance schedule or certifying the predefined maintenance schedule for the fleet of aircraft from the discrete event simulation of the process. The method further includes performing maintenance on the fleet of aircraft by the system according to the maintenance schedule or the predefined maintenance schedule.