The invention relates to an arrangement, in a pod of an aircraft propulsion assembly, for drawing in air and trapping foreign bodies. Said arrangement includes a main air inlet duct (11) separating into, on one hand, a channel (13) for leading air to a compressor and, on the other hand, a bypass channel (12) capable of trapping foreign bodies (5) that enter said main duct (11). Said arrangement comprises a heat exchanger (6) that extends along a section of the bypass channel (12). Said heat exchanger (6) carries out surface heat exchange along said section and is coupled with an external oil system in order to cool the oil thereof by heat exchange with the air (4) flowing in the bypass channel (12). Said bypass channel (12) has an air outlet (12a) acting as a means for discharging the foreign bodies (5).