Abstract: An aircraft-mountable inflow and outflow apparatus has an accumulating sleeve, an inflow line and at least one exit opening. The regulating sleeve has an entry opening. The inflow line has a supply-line connection for a respective supply line. The accumulating sleeve forms a first supply-line portion, is designed for insertion into a respective shaft of the respective inflow and outflow apparatus and is dimensioned such that, in a state in which the insert has been inserted into the respective shaft, the entry opening of the accumulating sleeve is located in the vicinity of an opening between a respective head part and the respective shaft of the respective inflow and outflow apparatus. Furthermore, the accumulating sleeve is connected to the supply-line connection for a respective supply line via the entry line, which constitutes a second supply-line portion.