What was found
FLT 4110 - WHEN SELECTING GEAR DOWN ON APPROACH TO A00, CREW UNABLE TO GET GEAR SAFE LIGHT NLG. CYCLED GEAR SEVERAL TIMES, STILL UNABLE TO GET SAFE LIGHT NLG. CREW ELECTED TO RETURN TO PIT, UNABLE TO VERIFY NLG DOWN, CREW DECLARED AN EMERGENCY. AFTER DECLARING AN EMERGENCY, NLG GREEN LIGHT ILLUMINATED. AIRCRAFT LANDED WITHOUT DIFFICULTY. EMERGENCY EVACUATION NORMAL. MAINTENANCE INSPECTED AND CLEANED NLG DOWNLOCK MICROSWITCH, CONDUCTED LANDING GEAR SERVICING. OPS CHECKED GOOD. ACFT RETURNED TO SERVICE.