Aircraft systems have increased in number and complexity since 1985. The integration test rig, often known as the "iron bird" integration simulator, has been developed to assemble and test as many as possible of the various aircraft systems in a simulated environment.

The integration simulator aims at:

- Stimulating the real aircraft equipment

- Simulating the aircraft environment, the natural flight loop and certain systems

The evolution, in the last twenty years, of simulators for aircraft equipment validation is presented in this article.

From 1995 to 2008, integration simulator  architecture has taken various evolutionary steps that have affected:

- Simulation complexity

- Simulation architecture

- Technology used

The article shows how mass-market technology (hardware, communication, bus, operating system) can fit into the specific and complex architecture of the integration simulator. The multiple technical and industrial constraints that must be taken into account to migrate from specific to generic solution will be presented.