Mike_UEM
That took longer to arise as a comment than was expected....
25.903(d)
(1) Design precautions must be taken to minimize the hazards to the airplane in the event of an engine rotor failure or...
and that doesn't seem to fully answer the question, but, AC20.128A ?DESIGN CONSIDERATIONS FOR MINIMIZING HAZARDS CAUSED BY UNCONTAINED TURBINE ENGINE AND AUXILIARY POWER UNIT ROTOR FAILURE of 25 MArch 1997 states in para 6 (c) of definitions:
Uncontained Failure: For the purpose of airplane evaluations in accordance with this AC, uncontained failure of a turbine engine is any failure which results in the escape of rotor fragments from the engine or APU that could result in a hazard. Rotor failures which are of concern are those where released fragments have sufficient energy to create a hazard to the airplane.
That was put out by the Mangler of TAD-ACS out of Seattle, Mike Kaszycki... for "harmonization".
The inlet looks like it would make a great paddling pool while the engine was an excellent cigar lighter.