What was found
ON LANDING IN FLAGSTAFF, AZ, RIGHT MAIN LANDING GEAR SHOWED UNSAFE (NO GREEN LIGHT). BULB TESTED OK. LANDING GEAR MANUAL EXTENSION QRH PROCEDURE WAS PERFORMED RESULTING IN GOOD LANDING GEAR CONFIGURATION (3 GREEN, NO RED LIGHT IN HANDLE). EMERGENCY WAS DECLARED AND LANDING ACCOMPLISHED WITHOUT INCIDENT. QRH PROCEDURE PERFORMED, EMERGENCY DECLARED. CORRECTIVE ACTION: CHECKED AND ADJUSTED LANDING GEAR DOWN-LOCK SWITCH AND ACTUATOR RIGGING. COMPLETED SATISFACTORY GEAR RETRACTION / EXTENSION CHECKS WITH NO DEFECT NOTED.