What was found
THE AIRCRAFT WAS ON APPROACH, WHEN THE LANDING GEAR WAS SELECTED DOWN. NEITHER THE TRANSIT NOR THE DOWN AND LOCKED GREEN LIGHT CAME ON. AN EMERGENCY WAS DECLARED. THE AIRCRAFT LANDED AND TAXIED TO THE GATE WITHOUT FURTHER ISSUES. MAINTENANCE FOUND THAT THE NOSE GEAR UP-LOCK INDICATION SWITCH HAD FAILED. THE SWITCH WAS REPLACED. GEAR OPERATIONAL CHECK PERFORMED AND THE AIRCRAFT RETURNED TO SERVICE. (K)