What was found
DURING HEAVY MAINTENANCE, AFTER TAKE-OFF AFTER GEAR RETRACTION ECAM MESSAGE: L/G GEAR NOT UPLOCKED FOLLOW ECAM ACTIONS AND QRH PROCEDURES STILL L/G NOT LOCKED UP. AT GEAR EXTENSION NORMAL GEAR DOWN AND LOCK 3 GREEN LIGHTS; PERFORMED TSM OF LG UPLOCK TGT POSITION FAULT ON NLG IAW TSM 32-31-00-810-837-A. DUE TO FAULT CONFIRMATION REMOVED AND REPLACED SENSORS 12GA,13GA, AND 37GA IAW AMM 32-31-73-000-005-A AND AMM32-31-73-400-005-A. PERFORMED FUNCTIONAL TEST OF THE NORMAL EXTENSION AND RETRACTION OF THE LANDING GEAR IAW AMM 32-31-00-720-002-A CHECK AND TEST ARE OK. AEROMAN TECH 8623008, AEROMAN INSPECTOR 8606312.