Described herein is a pilot monitoring system (100) including a camera (106) configured to capture a plurality of digital images of an aircraft (104) cockpit including one or both of a pilot (102) and a co-pilot (103) and a processor (114) configured to process the captured images. The images are processed to determine an alertness state of the pilot (102) and/or the co-pilot (103) during operation of the aircraft (104) based on detected facial features of the pilot (102) and/or co-pilot (103) in the images. Processor (114) receives information indicative of a current phase of flight of the aircraft and displays a visualisation of the alertness level and/or determines a suitability of a controlled rest period for the pilot (102) or co-pilot (103) based on the alertness state of the pilot and (102)/or the co-pilot (103) and the current phase of flight. An alert is issued alert to the pilot (102) and/or co-pilot (103) including a determination of a suitability of a controlled rest period for either the pilot (102) or co-pilot (103).