Abstract: A double-wall pipe for an aircraft fuel system includes an inner wall defining a first open end, a second open end, and an inner region connecting the first open end to the second open end and via which a fuel is flowable through the double-wall pipe, in use. The double-wall pipe includes an outer wall at least in part around the inner wall to define an interspace, between the inner wall and the outer wall, that is fluidically isolated from the inner region. The double-wall pipe includes at least one barrier that is openable to create a passage that fluidically connects the interspace to the inner region. The at least one barrier is configured to open when a pressure in the interspace is higher than a pressure in the inner region.