Smelled burnt oil aroma at shutdown....everything else perfect.
Refuelled....flew up to the top of a 10,000 foot mountain....no problems.
Landed and shutdown for an hour....cranked and picked up to a hover no problems.
Checked all was well but heard an "odd" but not worrisome sound....re-checked the instruments...all was well. Departed.
Once well away from the mountain....lowered the collective...."BOOM!", sudden yaw....noises from a Chinese/American Indian mix...."UGH...LEE".
Weird instrument indications....N1 was above idle, N2 was varied with collective, Nr went with collective movement somewhat normally....landed with no damage beyond the normal laundry issues.
Seems a main bearing in the engine had gone....turning the rotors by hand turned the engine.
There is no such thing as a "standard" engine failure.