What was found
ON SLAT EXTENSION DURING APPROACH FOR LANDING AT PDX, THE SLAT DISAGREEMENT LIGHT ILLUMINATED, THE SLAT EXTEND LIGHT DID NOT ILLUMINATE, AND THE AIRCRAFT EXPERIENCED AN UNCOMMANDED ROLL TO THE RT. COM PROCEDURES WERE PERFORMED AND THE FLIGHT CREW DIVERTED TO BOS DUE TO THE LONGER RUNWAY AND MAINTENANCE AVAILABLE THERE. MAINTENANCE WAS UNABLE TO FIND ANY ABNORMALITIES OF THE SLAT SYSTEM. THE REPLACEMENT OF THE RIGHT 'T' DUCT HAS BEEN DEFERRED.