What was found
MIA/KIN - FLT JM 020 - AIRCRAFT RETURNED TO MIAMI AFTER TAKEOFF DUE LANDING GEAR WOULD NOT RETRACT. ECAM REPORT SHOWED NLG PROXIMITY SENSORS 24GA, 25GA, AND LGCIU 1 AT FAULT. THE PROXIMITY SENSORS WERE FOUND COVERED WITH GREASE DURING INSPECTION; BOTH SENSORS WERE SUBSEQUENTLY CLEANED. AIRCRAFT WAS DEPOWERED AND LGCIU FAULT DISAPPEARED WHEN POWER RESTORED. BITE TEST OF LGCIU AND PROXIMITY DETECTORS 24GA AND 25GA TESTED OKAY. AIRCRAFT WAS THEN DISPATCHED. (X)