It seems a bit of bravado by DY to suggest that it has a provable case against Boeing at this point. While I absolutely agree that various regulators quite properly grounded the aircraft, that does not mean that Boeing either did anything wrong or is liable. If it turns out that the grounding was not warranted by any action Boeing did or did not take, DY will have thrown good money after bad. But, in desperate times, that may be all that is left.