What was found
(CAN) WHILE IN CRUISE AT 18,000 FT, CREW EXPERIENCED LOSS OF POWER ON LT ENGINE. PRIOR TO LOSS OF POWER CREW DID NOT RPT ANY UNUSUAL IND.S. CREW FEATHERED & SECURED ENGINE & LANDED AT NEAREST AVAILABLE FACILITIES. MAINTENANCE REPORTED THAT ENGINE NOT SEIZED, BUT THAT UNUSUAL NOISE CAN BE HEARD FROM GEARBOX AREA UPON ENGINE ROTATION. SUBSTANTIAL AMOUNTS OF NON-FERROUS MATERIAL, ALONG WITH LESSOR AMOUNTS OF FERROUS MATERIAL, FOUND IN ENGINE MAIN OIL FILTER. CHIP DETECTOR CONTAINED SMALL AMOUNTS OF FERROUS MATERIAL. ENGINE REMOVED & IS PRESENTLY ON STAND AT ENGINE SHOP IN WINNIPEG, MAN. PRELIMINARY TEAR DOWN INVESTIGATION REVEALED THAT IDLER GEAR ASSY BEARING FAILED.