What was found
ETOPS - ZONE A ZONE CONTROLLER TRIM AIR VALVE KEEPS FLUCTUATING HARD TO CONTROL TEMP IN FIRST CLASS, ALL OTHER ZONE OPS NORMAL.// REPLACED TRIM AIR VALVE PER A330 AMM 21-63-51. COCKPIT AND CABIN TEMP CONTROL TEST OK. OK FOR SERVICE. VALVE, TRIM AIR OFF 33-2160-9-0005 S/N 36870 ON 33-2160-9-0005 S/N 21425