Safety is a matter of Technology, Organization and People (the TOP model: Boy, 2013); it is a matter of human-systems integration (HSI). However HSI, especially when systems are life-critical, requires us to make a distinction between Technology-Centred Engineering (TCE) and Human-Centred Design (HCD). TCE leads to situations where human operators need to do most of this integration at operations time. Conversely, HCD is deliberately based on HSI at design time. Of course, the HCD approach does not remove the need for human operators' expertise and experience at performance time, but provides solid foundations for HSI at systems delivery. In this paper, I will use the metaphor of the Orchestra to describe the HCD approach, where human operators (musicians) share the same frame of reference (music theory), have integrated tools and tasks (music instruments and scores) coordinated by HCD specialists (composers), are coordinated at performance time by technology knowledgeable and skilled leaders (conductors), and are knowledgeable about the recipients of their work (the audience). Making and playing a symphony involves many risks that need to be managed. These risks can be managed by design, using the TOP model, where human-centred designers create, test and certify technology, corresponding organization and people's jobs involved. Creativity is not only deliberate; it is often a matter of discovery of emergent properties of what is being created. For this reason, human-in-the-loop simulations and formative evaluations are mandatory. This paper will explain HCD processes that support managing risk by design.< Réduire