What was found
LANDING GEAR DID NOT EXTEND. ECAM PROCEDURE LDG GEAR MANUAL EXTENSION. LANDING GEAR DOWN AND LOCKED W/ MANUAL EXT. WHEN GEAR HANDLE WAS PUT DOWN NOTHING HAPPENEDAFTER GO AROUND PERFORMED QRH/ECAM LG GRAVITY EXTENSION. AFTER COMPLETING OF QRH OVERHEAD PANEL SHOWED NOSE GEAR NOT EXTENDED BUT ON LOWER PANEL SHOWED DOWN AND LOCKED. AFTER LOW APP BOTH SYSTEMS SHOWED DOWN AND LOCKED. REMOVED AND REPLACED VALVE 3GA REF AIRBUS A300-600 AMM 32-31-12-04 OPS CK GOOD NO LEAKS NOTED.