What was found
(CAN) DURING CRUISE, PILOTS SMELLED SMOKE IN COCKPIT. AT SAME TIME FLT ATTENDANT NOTIFIED COCKPIT THAT LAVATORY SMOKE DETECTOR HAD GONE OFF. A/C DEPRESSURIZED & EMERG DESCENT MADE, FOLLOWED BY UNSCHED LDG IN LA RONGE, SK. AIR-COND SYS OPERATED NORMALLY ON SUBSEQUENT MAINT GROUND RUNS (NO SMOKE). INVEST. OF CAUSE REVEALED THAT NR 1 SUPERCHARGER HAD DAMAGED ROTOR. APPROX 4 SQUARE IN OF MATERIAL W ERE BROKEN OUT OF ROTOR. DOWNSTREAM DUCTING&COMPONENTS WERE REMVD&INSP FOR DAMAGE & CONTAMINATION, WITH NONE FOUND. ACCESSORY GEAREBOX INSP FOR DAMAGE WITH NONE FOUND. SUPERCHARGER REPL WITH SERVICEABLE UNIT, & A/C DISPATCHED WITH NO FU