Real Time Feedback reported air discharged sound heard at front DT car. Staff (WDL) checked and conf irmed no abnormalities. ~~~~~ Real Time Feedback reported air discharged sound heard at front DT(3621) car. Staff (WDL) checked and confirmed no abnormalities.  3621 found air dryer keep purging whenever changeover. Check No FC of air dryer. Repplace Air dryer and function test ok. Monitor no occurance of fault. Air leak 0.3bar/5min Done by Saini/Asruddin/Haslan KSF AIR DRYER OLD:3515289113 NEW:3514320184 NOTIF:2561638