What was found
BIS - FLT NR 421 - CREW REPORTED, THE RIGHT MAIN LANDING GEAR INDICATED DOWN IN FLIGHT AND THE AIRCRAFT HAD A YAW TO THE RIGHT. THE AIRCRAFT LANDED AND INSPECTION REVEALED THAT THE RIGHT UPLOCK ROLLER AND ATTACHMENT BOLT WERE MISSING, CAUSING THE RIGHT GEAR TO NOT LOCK UP. ALSO, THE UPLOCK SWITCHES WERE DAMAGED CAUSING THE HYDRAULIC POWER TO BE CUT OFF FROM THE LANDING GEAR SYSTEM, LETTING THE RIGHT GEAR FALL TO THE DOWN AND LOCK POSITION. BOTH RIGHT UPLOCK SWITCHES AND THE UPLOCK ROLLER WERE REPLACED. A GEAR RETRACTION TEST WAS COMPLETED AND THE AIRCRAFT WAS RETURNED TO SERVICE. (M)