  This paper presents research results that develop a dynamic logic for
reasoning about safety-critical information flow among humans and computers.
The logic advances previous efforts to develop logics of agent knowledge, which
make assumptions that are too strong for realistic human agents. We introduce
Dynamic Agent Safety Logic (DASL), based on Dynamic Epistemic Logic (DEL), with
extensions to account for safe actions, belief, and the logical relationships
among knowledge, belief, and safe action. With this logic we can infer which
safety-critical information a pilot is missing when executing an unsafe action.
We apply the logic to the Air France 447 incident as a case study and provide a
mechanization of the case study in the Coq proof assistant.
