A method and system are disclosed for assessing the capability of a first person to operate a machine, such as an aircraft or other transport vehicle. The method includes the steps of: (a) Sensing the value of at least one, and preferably two or more information parameters for assessing the fitness of the person operating the machine. The parameters include one or a combination of electroencephalogram information, electrocardiogram information, heart rate information, respiratory rate information, eye motion information, eyelid position information, eyelid motion information, expired gas mixture information, blood oxygen content information, blood oxygen saturation information and blood pressure information for the person operating the machine, and/or information about operation of the machine as well as information about actions taken by the person operating the machine. (b) Determining whether at least one value of one information parameter is/are not within the range of values deemed to be acceptable for a capable person. (c) Indicating when the at least one information parameter is/are not within the range of acceptable values, thereby indicating the person's decreased fitness and ability to operate the machine.