On layman54's summary of the Complaint;
Sorry to return to law prof mode for a moment. The Federal Tort Claims Act waives, that is it removes, federal sovereign immunity. The statute also provides for continued sovereign immunity for federal government "discretionary functions", hence the "exception" is to the waiver of immunity. But the standard for whether a particular allegedly negligent act or omission was, or was not, within the meaning of "discretionary function" is something of a binary statement: if the action was a "ministerial action", then it did not involve the exercise of discretion as meant by the statute. Ministerial actions (though perhaps over-simplifying) are actions applying or following regulations or rules, or perhaps standardized procedures.
If my recollection of federal procedure is accurate, the federal defendants (FAA, and its statutory parent entity, Department of Transportation, and the Army) will need to assert sovereign immunity in motion practice of some sort, or possibly as an affirmative defense that needs to be pled in their (presumably) respective Answers to the Complaint - tbh I'm not certain which (but I'm not re-engaging the yoke of billable hours where I can avoid it).
My prior post thus was imprecise (apologies). The words "discretionary function exception" would not be expected to appear in this Complaint. But the several references to specific FAA rules and other written procedural-type stuff - I see these as carrying two loads. The first is the obvious one of making a strong case that this accident was caused, in major part, by FAA's negligence. FAA and the DOT can argue all they want about the several actually discretionary decisions which are implicated in the structure and operation of that airspace on the night of 29 January (federal legislation about capacity, being a headline among them, perhaps paired with the often-decried FAA basic idea of moving traffic over most other factors). But all those arguments will not bar the plaintiffs from arguing that in additionto discretionary policy decisions, FAA also violated its own rules and procedures. Which would be a serious argument that insofar as those rules and procedures are concerned, FAA was taking ministerial action, i.e., negligent ministerial action.
The Army's situation is more straightforward imo. Certainly a good number of discretionary functions are involved, or were involved, in the operation of the type of helicopter flights involved in this accident, in general, and specifically as training missions. But the altitude deviation and related operational factors do not fit within the scope of the discretiionary function exception to the waiver of immunity.
I recall some poster months ago stating that during the last leg of the approach, the PSA pilots "owned that airspace" or words to that effect. At a perhaps monkey-brain level, I agree with what the airline legal counsel is reported to have said: the helicopter flew into our airplane. But realizing I'm not objective (plus the fact this being a pilots' forum....) it is sickening to see those pilots alleged to have been negligent.