What was found
PASSING 9000 FEET ON CLIMB OUT, WHILE ACCELERATING, LEVEL 2 SLAT DISAG. ALERT. COMPLIED WITH QRH. ALERT WAS SPURIOUS AND WENT OUT PRIOR TO CRUISE ALTITUDE. ALERT RETURNED ON DESCENT CAUSING SPURIOUS AIRSPEEDS ON APPROACH. COMPLIED WITH QRH, PERFORMED A FLAPS 28/RET LANDING. SHGN 12MAR22 15:04 SYD U T/S PER FIM: 31-71-07-00. NO FAULTS NOTED ON PROX UNIT. OPERATED SLATS PER AMM: 27-80-00-2 AND ALL FOUND NML. WORK IN PROGRESS. REPLACED 4B SLAT POSITION SENSOR PER AMM 27-84-03-4, OPS CHECK C/OUT OK. FCC 1 & 2 RTS PASSED PER AMM 22-00-00-5. A/C OK FOR SVC.