The invention relates to an installation (1) for detecting and locating a leak in at least one fluid transport circuit (Ps, Pt), notably an anemometer circuit of an aircraft, having a leak test apparatus (10) including means (12) for detecting a leak in the said at least one fluid transport circuit (Ps, Pt). In one example, the means for locating a leak includes injecting means (Pp, 14, Ev2) of a trace gas under pressure into the said at least one fluid transport circuit (Ps, Pt), which means are situated in the said leak test apparatus (10), and a trace-gas detection probe (30) intended to be moved along the said at least one fluid transport circuit (Ps, Pt) on the outside thereof, in order to locate the leak.