Originally Posted by
Stumpy Grinder
Incorrect, a turbine blade release is considered as having infinite energy and is not contained - see Qantas QF32 A380 as an example. For cert compliance you have to show that no catastrophic event can occur as a result of a turbine blade release. For instance, if an APU turbine blade releases then it has to be demonstrated that the trajectory of the release does not compromise primary structure or flight controls, ie the release is satisfactorily mitigated by design.
Also it's not the cowl that contains the fan blade in the event of a FBO, it is the engine case.
Blades are supposed to be contained.
See
https://en.wikipedia.org/wiki/Blade_off_testing
You are talking about turbine discs and fan discs, the central parts of metal holding all the blades.
But I guess you know that as you refer to a turbine disc failure (QF32).