Abstract: A sensing probe 10 for use in determining fluid flow rates along a duct 11 comprises a probe pipe 12 mounted within a wall of the duct 11 to extend thereacross. A plurality of total pressure orifices 17 are provided through the probe wall, to face fluid flow, and a single static pressure opening 18 is provided on the downstream side of the probe. An averaging tube 19 is mounted within the pipe and has two openings 20 suitably disposed with respect to the duct axis so that the pressure within the averaging tube closely approximates to the average total pressure for the flow rate determination. The static pressure orifice 18 communicates with a further tube 23 within the pipe, to allow sensing of a pressure directly related to the actual static pressure.