What was found
ON PRE-FLIGHT, THE COPILOT DISCOVERED DAMAGE TO THE RIGHT FAN ASSY WHICH RESULTED IN THE FLIGHT BEING CANCELLED. FOUND DAMAGE TO 12 BLADES RANGING FROM SMALL NICKS TO A SECTION MISSING FROM THE TIP OF ONE BLADE THAT WAS APPROX .25 SQUARE INCH IN SIZE. THE INFORMATION WAS SENT TO P & W-CANADA TO DETERMINE IF ACFT COULD BE FLOWN TO A MAINT SHOP TO EFFECT A REPAIR. THE FAN WAS DISASSEMBLED AND 10 SERVICEABLE BLADES INSTALLED. THE ASSY WAS BALANCED AND RE-INSTALLED. THE CORE WAS INSPECTED AND NO DAMAGE NOTED. APPARENTLY, THE PIECES EXITED THROUGH THE BYPASS DUCT.