There's an excellent A List Apart article titled Fire Drills: Communications Strategy in a Crisis that details how to create a framework/protocol to deal with downtime. It describes how to create a work structure to handle the downtime including how to organise people into different roles, and how to communicate efficiently to the outside world about what is broken, and what is being done to fix it.
The key sentence for me is:
"The protocol makes these kinds of decisions ahead of time, reducing the cognitive load on the response team during the emergency"
Common sense but unfortunately not very common place. This is a very enlightening article, describing a somewhat simple framework that can be applied and scaled to companies/projects of any size.