Abstract: A fluid flow sensing instrument is described which in its specific embodiment comprises an anemometer. Three sensor bearing arms are provided, all at the same azimuth. Three components of the fluid flow are thus simultaneously detected. By having the arms at the same azimuth greater precision is obtained in measuring both the directionand intensity of the fluid vector than with instruments having their sensors in a standard cartesian arrangement. The instrument is thus better adapted to suit the requirements of environmental studies concerning the atmosphere.