Simulation is often used for training personnel in activities where the consequences of inappropriate actions are serious. We report a realistic training simulator, which can reproduce practically all potential malfunctions in the anaesthetic machine. Using actual standard equipment (Dameca 10750), the interior of the anaesthetic machine has been profoundly modified, whereas the external appearance remains virtually unchanged. The concealed alterations allow 20 different pre-set technical faults to be activated selectively from a mobile control unit. While assisted by an instructor, the trainee performs hands-on interactive experimentation with the simulator, while being exposed to 'unexpected' machine faults, which prompt for interpretation of error symptoms. Alternatively, the trainee can personally activate the simulated symptoms of different component failures, to enhance learning of the functional principles of the apparatus. The latter approach also allows a systematic presentation of defects to be identified by each step in a formal safety checklist for anaesthetic machines.