Abstract: Means for reducing blockage of cooling apertures in a hollow gas turbine guide vane by sand or other particles entrained in cooling air, is provided by a partition within the vane for dividing the hollow region into first and second regions, the first region having a flow of high pressure cooling air, the second region being at a pressure lower than the first region. The partition is provided with a channel on the high pressure side. Apertures are located in the base of the channel providing flow between the first and second regions and directing cooling air at the inside surface of the vane. The inlet area of the channel is greater than the total cross-section area of the apertures, and the width of the channel distal to its base is less than or equal to the diameter of the apertures, thus trapping in the channel entrained particles larger than the diameter of the apertures.