LCNs CBRs and allthat jazz
ME you asked for a tutorial on LCNs. LCN, ACN, PCN and ESWLs are merely different ways of telling you the same thing - measuring the requirements of an aircraft against the load bearing capabilities of a runway surface. They all apply to paved surfaces ie "real" airfields and their runways and taxiways. In the case of military transport aircraft the actual requirement can, occasionally, be improved by reducing the tyre pressures.
However, when you are talking about operations off and onto natural surfaces - grass, shale, mud, sand etc - California bearing ratios are used or CBR. As its name says it is a ratio and does not have a unit to go with it. From memory of Boeing's own figures the minimum CBR for a C17 is about 10 if it is to do anything at all. A400M is designed to be able to do a minimum of 120 passes at CBR 6 (a pass being a landing or take off) and 10 passes at CBR 4. Again from memory C130 is similar but I don't have any details. CBR 4 is a mid-winter sports pitch that even a landrover would cut up whilst CBR6 is possibly a spring time Rugby 7s type pitch.
At CBR 6 A400M 500 nm from main base could make about 140 landings and deliver round about 3,200 tonnes of freight etc before the strip needed repairing or moving.
I hope this helps your discussions.