I believe the shoot down of the Chinook was an act of war, but if you'll allow me, I'd like to to stretch the definitions of tragic and tragedy, and talk about a few "for instances" that satisfy the parameters of those words:
It is tragic that the area in which Extortion 17 was operating had already been cleared by U.S. warriors three previous times according to the military, but had not been maintained by the Afghans who were charged with manning the area and keeping it safe.
It is tragic that in America the warriors on that chopper were trained as SOF (Special Operations Forces) while at the same time, the pilots and crew of the chopper were trained as conventional forces. But according to the military, the two groups do not work together until they've reached the theater of battle.
It is tragic that the thirty Americans who gave all for this republic were forced to fly a mission that night so risky that it had to be OK'd out of theater and then were left no options but to board a CH47 Chinook, last retrofitted in 1984 and 85. The warriors on board that ancient bird were either little boys or had not even been born during her remodel. How many politicians or dignitaries would be willing to fly into Afghanistan in the safest area, in broad daylight, in such a craft?
Personally: I think they were set up.