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 MAIN LANDING GEAR DOOR BY PASS VALVE PER AMM 32-31-13 AND INSTALLED CABLE TO BYPASS VALVE PER AMM 32-12-16. ACCOMPLISHED SATISFACTORY OPERATIONAL AND LEAK CHECKS. ACCOMPLISHED GEAR EXTENSION AND RETRACTION PER AMM 32-30-00. (SEE ALSO AALA201704179054).