Ground based test of avionics systems is an essential part of the certification process for any modern aircraft. Test rigs have to be constructed to interface to the various systems, and stimulate them electrically in a correct and timely fashion to simulate the appropriate flight regime. So, such a test rig will itself be a hardware in the loop system; furthermore, in order to test the systems in a typical modern passenger aircraft, it will have a number of other objectives that it must satisfy. It is the scale of the system that presents the greatest challenge for the design of hardware in the loop test for the A380 avionics systems.