"I'll litter the thread with legal stuff only a little more here. Anyone following the thread has seen posts about the application of part of sovereign immunity to claims against the Army and the FAA/DOT, despite the Federal Tort Claims Act. Specifically, sovereign immunity continues to apply where the alleged negligence resulted from a federal entity exercising "discretion" in making some decision based on weighing competing policy interests and requirements (apologies both for repeating myself from prior posts, and for the legal readers, for oversimplifying). ..."
I continue to doubt the discretionary exception will be important to this case. In my view the helicopter crew was clearly negligent (in ways that are not covered by the discretionary exception) and that is all that is needed to make the government liable. There is no need (and it would probably be inadvisable) for the plaintiffs to bring in anything that might be covered by the discretionary exception.
If I were the government I would be trying to settle these cases. I expect there are plenty of plaintiffs (and even some plaintiff's lawyers) who would rather have a certain $x now instead of an uncertain $3x in 5 years.