What was found
AIRCRAFT WAS GNDED. ON APPROACH TO LANDING, LG WOULD NOT EXTEND & CREW NOTED 3 RED INDICATION LIGHTS. GEAR WAS EXTENDED MANUALLY & RECEIVED 3 GREEN INDICATION LIGHTS. CREW DECLARED AN EMER, HAD TOWER CONFIRM GEAR WAS DOWN & LANDED SAFELY WHERE THE ACFT WAS TOWED TO THE GATE. REPLACED THE NR 1 AIR DATA & INERTIAL REFERENCE UNIT IAW AMM 34-12-34-0401 & REPLACED THE NR 1 LG CONTROL INTERFACE UNIT IAW AMM 32-31-71-0401. ACCOMPLISHED A SATISFACTORY OPERATIONAL CHECK OF THE LG. SEE AALA 201604289005 FOR ADDITIONAL PART INFORMATION.