AN MD-SUPER 80 FO RPTED THAT THE CAPT WAS UNABLE TO KEEP THE ACFT FROM DRIFTING RAPIDLY TO THE L UPON LNDG AT CYUL. THE FO ATTRIBUTED THE DRIFT TO RUDDER BLANKING AND TO HIS COMPANY'S 1 PT 6 EPR PROC IMMEDIATELY AFTER LNDG.

Narrative

OUR FLT WAS DELAYED IN ORD FOR MAINT; THEN LEFT ABOUT 1 HR LATE FOR YUL. ENRTE ATIS SAID TWRING CUMULUS (TCUS) NEAR FIELD AND 6100 FT OVCST; WINDS 280 DEGS AT 8 KTS. IN DSCNT TOLD BY APCH THAT MODERATE CHOP RPTED FROM 9000 FT TO 12000 FT. WE GOT THE CHOP ALL THE WAY DOWN TO 1500 FT. ALSO GOT SEVERAL MAJOR SHOWERS BEFORE GETTING ON FINAL. FROM 1000 FT DOWN; THE APCH WAS FINE; NO CHOP AND NO MORE RAIN; BUT FIELD OBVIOUSLY VERY WET. WINDS RPTED 310 DEGS AT 10 KTS GUSTS TO 20 KTS. USING SPDS FOR 122000 LBS PLUS 15 KTS. WE LANDED RIGHT ON SPD AT 143 KTS; ON CTRLINE; IN THE LNDG ZONE. ALL SYS WORKED AS ADVERTISED; SPOILERS; AUTOBRAKES; AND REVERSE. SHORTLY AFTER CAPT GOT TO 1.6 EPR; ACFT DRIFTED RAPIDLY TO L. FULL RUDDER AND AILERON FAILED TO STOP DRIFT. CAPT CAME OUT OF REVERSE STOPPING OUR DRIFT ON THE L SIDE OF THE RWY. SINCE HE KEPT THE ACFT FACING DOWN THE RWY WE DIDN'T FISHTAIL; JUST DRIFTED. THIS HAPPENED SO FAST I WAS REALLY SURPRISED. I BACKED HIM UP ON THE CTLS AND TALKED ABOUT CTRLINE; BUT WITH THE RUDDER BLANKED THERE IS LITTLE YOU CAN DO BUT COME OUT OF REVERSE. I COMPLETELY DISAGREE WITH THE 1.6 EPR PROC IMMEDIATELY AFTER LNDG; THAT IS WHAT CAUSED OUR PROB. IT ALSO WOULD HAVE BEEN NICE TO KNOW HOW WET THE RWY WAS. NO BRAKING ACTION RPTS WERE GIVEN. THEY MAY NOT HAVE HAD TIME AS IT WAS A SMALL BUT FAST MOVING STORM.