A duct mount averaging pitot tube assembly for use with a duct to measure a flow of fluid in the duct, the APT assembly comprising: an APT primary element extending longitudinally between a first end and a second end, the APT primary element having first and second internal chambers (515, 525) extending longitudinally between the first and second ends, the APT primary element having an upstream face with an upstream opening which opens to the first internal chamber and extends from the first end to the second end, and a downstream face with a downstream opening which opens to the second internal chamber and extends from the first end to the second end; first and second duct mount flanges (430, 432) configured to respectively mount the first and second ends of the APT primary element to the duct when the APT primary element is inserted in the duct; a flange plate; characterized in that, the duct mount averaging pitot tube assembly further comprises first and second flare fittings on a first side of the flange plate and configured to be inserted into the first and second internal chambers at the corresponding end of the APT primary element; and a cowl on the first side of the flange plate surrounding the first and second flare fittings and configured to receive the corresponding end of the APT primary element when the first and second flare fittings are inserted into the first and second internal chambers; wherein the APT primary element is shaped to be cuttable between the first end and the second end to change the length of the APT primary element while maintaining end profiles of the APT primary element, wherein the first and second flare fittings are sized larger than the first and second internal chambers to form a sealing fit when the first and second flare fittings are inserted into the first and second internal chambers. an APT primary element extending longitudinally between a first end and a second end, the APT primary element having first and second internal chambers (515, 525) extending longitudinally between the first and second ends, the APT primary element having an upstream face with an upstream opening which opens to the first internal chamber and extends from the first end to the second end, and a downstream face with a downstream opening which opens to the second internal chamber and extends from the first end to the second end; first and second duct mount flanges (430, 432) configured to respectively mount the first and second ends of the APT primary element to the duct when the APT primary element is inserted in the duct; a flange plate; characterized in that, the duct mount averaging pitot tube assembly further comprises first and second flare fittings on a first side of the flange plate and configured to be inserted into the first and second internal chambers at the corresponding end of the APT primary element; and a cowl on the first side of the flange plate surrounding the first and second flare fittings and configured to receive the corresponding end of the APT primary element when the first and second flare fittings are inserted into the first and second internal chambers; wherein the APT primary element is shaped to be cuttable between the first end and the second end to change the length of the APT primary element while maintaining end profiles of the APT primary element, wherein the first and second flare fittings are sized larger than the first and second internal chambers to form a sealing fit when the first and second flare fittings are inserted into the first and second internal chambers.