Safety is THE priority in aviation. The reason is obvious: people's lives are at stake and this is ingrained in the industry (operators and manufacturers, regulation agencies).

Instead of a wide description of the systems safety process, which is generally known and well documented, we will rather focus on a few important points, not always part of conventional wisdom.

We intend to show that safety process is fully embedded in design, that the ubiquitous and magic number of 10^-9    is only a tiny part of the solution, the multiple dimension of the issues and the overall resilience of the process.