What was found
ATB - ON APPROACH, AFTER GEAR EXTENSION "GEAR DOOR OPEN" ALERT CAME ON. RECYCLED THE GEAR AGAIN AND ALERT CAME ON. GEAR WAS DOWN AND 3 GREEN. NORMAL GEAR INDICATION WITH NO ALERT. AIRCRAFT RETURNED TO THE DEPARTING STATION, WHERE AN UNEVENTFUL LANDING WAS MADE. REMOVED AND REPLACED RH MLG DOOR ACTUATOR CYLINDER REF. AMM TASK 32-34-03000-801. OPS CHECK GEAR SWING, OK. OK FOR SERVICE.