Abstract: The present invention relates to apparatus for in-situ evaluation of the light flux of narrow and intense light beams, in particular those from the beacon lights of airport runways and taxiways. It comprises a closed box mounted in a pod placed on a moving chassis, the box has a translucent front face that diffuses the light flux from the beam to be measured omni-directionally inside the box, and another face having high diffusing reflection power that closes the box and provides both reflection and diffusion of the light in uniform manner towards a photoelectric sensor whose sensitive portion is disposed close to the front face, but facing said diffusing reflection face.

Abstract: An arrangement for mounting a cascade of guide vanes or other objects extending across a conduit, characterized in that there is provided within the conduit two longitudinal partitions or plates separated by a small gap, and in that said object is formed in two parts each of which has one end fixed to a wall of the conduit and the other to the longitudinal plate nearest to this fixing point.