A319 CREW HAD ACFT SPD SLOW TO 'ALPHA FLOOR' PROTECTION SPD AT FL350.

Narrative

ON LEVELOFF AT CRUISE ALT FL350; AIRSPD SLOWED TO 211 KTS; GREEN DOT. FO (PNF) NOTED SPD REDUCTION AND ADVISED CAPT (PF). ACFT WAS IMMEDIATELY RETURNED TO NORMAL PLANNED CRUISE MACH .80. ATTRIBUTE INITIALLY UNNOTICED SPD REDUCTION TO CAPT DISTR WITH FMGC ROUTING APCHING LEVEL AND CONFUSION WITH PRIOR BOEING GLASS DURING HIGH WORKLOAD. FO POINTED OUT ARR RTE DISCREPANCY DUE TO DIFFERENT LNDG DIRECTION AS ACFT WAS IN LAST PORTION OF FINAL CRUISE CLB. CAPT ATTN DIVERTED TO FMGC DURING LEVELOFF. ACFT WAS CRUISE CLBING IN SELECTED SPD AT .80 MACH. CAPT MONITORED LEVELOFF ALT; BUT DID NOT OBSERVE SPD BUG REDUCTION TO GREEN DOT DUE TO ATTN DIVERTED TO FMGC ROUTING. ROUTING ISSUE WAS SOLVED WITH CHANGE OF RWY. PERFORMANCE PAGE CRUISE AIRSPD HAD APPARENTLY BEEN INADVERTENTLY CHANGED AFTER THE INITIAL FMGC INFO HAD BEEN CHKED BY BOTH PLTS. IT APPEARS THE INITIAL CLB SPD MAY HAVE BEEN INADVERTENTLY ENTERED ON THE CRUISE PAGE AT SOME POINT. CAPT PLANNED TO LEVEL IN SELECTED SPD OF .80 MACH. NO ATC ALT OR ROUTING DEV OCCURRED. AUTOPLT AND AUTOTHROTTLES ON DURING CLB AND LEVELOFF.