The invention relates to an air bleed system comprising an air bleed port provided on an engine of an aircraft, an air supply pipe, a pressure sensor, a pressure relief valve mounted in said air supply pipe, characterized in that said pressure relief valve comprises: a valve body (11); a closure member (121) pivotally mounted in said air circulation duct; and an air discharge channel (13) passing through said valve body (11); at least one air discharge opening (15) formed on said upstream face of said closure member (121) and at least one air evacuation opening (19) which opens out to the outside of the air circulation duct.