Originally Posted by
bsieker
Also, Concours77, what do you think could "blow out" the front of the engine in such a way that it only damages part of the cowling, which is a relatively weak material, but then is also powerful enough to snap off a fan blade, which is very strong indeed unless there already is a fatigue crack.
The only think I know which "blows out" of the front of the engine would be a surge, but these rarely damage the engine, although they can be spectacular. I can't imagine that one would ever blow out a fan blade.
Bernd
It wouldn’t have to be powerful enough to blow out an (undamaged) fan blade, only sufficiently robust to snap an already cracked one. An important piece of evidence is the character of the “bang”. Never present at an actual blade separation, but I have experienced a very impressive surge in a DC-10 (Mexicana, forty years ago). Number two. A LOT of flame, and a very loud “boom”.