Abstract: A system is (10) for determining a flight rest scenario for an aircraft crew (12) comprising at least two pilots able to fly the aircraft (12) during a flight. The system (10) comprises a display device (16) comprising a screen (20), a module (32) for acquiring flight context and constraints inputs, and a module (34) for determining at least one crew rest scenario for the flight from the acquired inputs. The determination module (34) is able to determine the rest scenario from at least one simulation by a biomathematical fatigue model having at least one of the acquired inputs as variables. The system also includes a display management module (36) configured to display the determined rest scenario on the screen (20) of the display device (16).