What was found
AIRCRAFT WAS GROUNDED. AFTER GEAR RETRACTION, LANDING GEAR DOORS NOT CLOSED, ECAM MESSAGE CAME ON. GEAR WAS CYCLED WITH NO CHANGE. AIRSPEED MAINTAINED BELOW 230. EMERGENCY DECLARED, FLIGHT RETURNED TO YYZ, NORMAL LANDING MADE AT YYZ. MAINTENANCE FOUND RIGHT HAND MAIN LANDING GEAR DOOR, MANUAL GROUND OPENING MECHANISM CABLE SHEARED FROM ACTIVATION HANDLE. REPLACED RIGHT HAND MAIN LANDING GEAR DOOR MANUAL GROUND OPENING CABLE PER AMM 32-12-16. (SEE AALA201704179050 FOR ADDITIONAL INFORMATION)