A helmet position detection system for aircraft including a helmet comprising a fixed visor used as an optical mixer and a substantially spherical mobile visor that is able to occupy a position of use and a stowage position, the visor being arranged in front of the pilot's eyes in the position of use. The helmet detects the position of the mobile visor and the helmet position detection system detects an orientation of the helmet corresponding to the pilot's line of sight and applies an angular correction due to the mobile visor to the orientation measurements when the mobile visor is detected in the position of use. Optical sensors are preferably used to detect the position of the mobile visor.