AN A319 FLT CREW EXPERIENCE A FAILURE OF THE BRAKE SYS RESULTING IN AN EMER LNDG AT DEN.

Narrative

AFTER DEPARTING SEA ARPT ON THE WAY BACK TO DENVER; WE GOT 3 SYS ALERT MESSAGES (NOSEWHEEL STEERING OFF; BRAKE SYS #1 FAILED; BRAKE SYS #2 FAILED). WE PERFORMED GEAR ACTION IN ORDER TO FIX THE PROB; BUT HAD NO SUCCESS. WHILE THE CAPT WAS ON COMMERCIAL RADIO WITH OPS; I WAS DIGGING IN THE BOOKS IN ORDER TO FIND WHAT WAS LEFT OF THE BRAKE SYS. FOUND OUT THAT ONLY ACCUMULATION PRESSURE WAS LEFT. CALCULATED LNDG DISTANCE TO BE ABOUT 700 FT IN THIS CONDITION. OPS COULD NOT GIVE POSITIVE ANSWER AS IF WE HAD BRAKES OR NOT. 40 MINS OUT OF DEST; CAPT DECIDED TO DECLARE AN EMER AND REQUESTED LARGEST RWY AVAILABLE. WE CALLED A FLT ATTENDANT ONTO FLT DECK IN ORDER TO EXPLAIN THE SIT. SHE WENT BACK IN THE CABIN TO BRIEF OTHER FLT ATTENDANT AND PAX. APCH WAS NORMAL; LNDG NORMAL; CAPT USED ACCUMULATION BRAKES AND REVERSE; ABOUT 8000 FT OF RWY USED TO STOP. SHUT DOWN ENGS AND GOT TOWED TO THE GATE. 2 VERY SENIOR FAA INSPECTORS WERE ON BOARD AND WERE FULLY INVOLVED IN THE DECISION PROCESS. THEY THOUGHT WE DID AN EXCELLENT JOB AND WERE MORE THAN SATISFIED WITH OUTCOME OF THE SIT. CAPT AND CABIN CREW DID AN OUTSTANDING JOB. WE NEVER EXERCISED THE EMER PRIVILEGES; DID NOT DEVIATE FROM ANY PROCS NOR CLRNC.