What was found
ON APPROACH LOWERED GEAR HANDLE, GEAR DIDN T EXTEND. RECEIVED 3 RED UNLOCK LIGHTS AND ECAM WARNING. ON THE GO-AROUND AS WE STARTED THE CLIMB, GEAR DROPPED AND WE HAD 3 GREEN DOWN AND LOCK LIGHTS AFTER ABOUT 30 SECONDS. LANDING GEAR NORMAL CONTROL MICROSWITCH UNIT - 2GA. REMOVAL AND INSTALLATION PER A300-600 A.M.M. 32-31-11-04. THE FOLLOWING INSPECTIONS, CHECKS, TESTS WERE PERFORMED: FUNCTION TEST OF MICROSWITCH UNIT, OPERATION TEST OF LANDING GEAR WARNING, CHECK OF ELECTROVALVE, PROXIMITY DETECTOR UNIT BITE. RESULTS: PASSED. THE AIRCRAFT IS OKAY FOR SERVICE.