In today's competitive airline environment, maintenance organizations must win contracts for high-quality repairs completed at low cost in the shortest possible time, or turntime. Rapid turntime is an important component of a marketing plan that emphasizes total quality customer service. This paper shows how a GPSS/H simulation model can be used as a tool useful to managers when evaluating either current maintenance system performance or the potential effects of ad hoc operating decisions on maintenance turntimes. The simulation data provided from these evaluations will provide maintenance vendors with more accurate information about their capabilities needed to market maintenance services successfully.