Could be major high tension runs that the AAS is referring to, but normal domestic supplies are all part of the mix that have to be considered when in and out of the smoke. Many are the SWR's that have loomed out of the murk when running in with a load on a long line
DSE do have a long standing preferred policy for belly tanks, their stated reasoning being both safety over the "urban interface", plus reduced risk in a wire environment. All contracted aircraft are required to have WSPS, although the cranes and S61's are exempted
But then the SAU and its policies have always been a bit of a mystery to outsiders
