A simulation modelling, using a simulation language SIMPLE++, was used to study the personnel capacity utilisation in a maintenance department. Input data included work orders with different throughput times, different personnel profile based on work order requirements, and different prioritisation rules. A decentralised maintenance department was assumed, whereby each department had its own maintenance unit. The effects of personnel organisational policies on the capacity utilisation of the personnel and on the throughput time of maintenance work orders were studied. The results of the simulation show that the best utilisation of the personnel and the best throughput time of maintenance work orders is obtained if the maintenance personnel are allowed to function across the borders of their department (here termed as exchangeability of personnel). Likewise, if there were universal maintenance personnel (i.e. who could take both electrical and mechanical work orders), then there would have been an optimum staffing of the maintenance department.