Abstract: The scheduling of maintenance for operational equipment is disclosed in which the operational equipment is distributed over many locations. Operational data relating to the use of operational equipment is received, along with equipment failure data. Stored operational data (501) is analysed (503) in combination with stored operational equipment failure data (502) to determine performance information (504) relating to extensive use of the operational equipment to rates of failure of operational equipment. New operational data is processed (505) along with equipment failure data in combination with the relationship information (504) to produce knowledge based output alert (506 to 509) and maintenance schedules (510).