FLC OF AN MLG LOST CTL OF ACFT DURING LNDG ROLL ON SNOW PACKED RWY RESULTING IN SLIDING OFF THE END OF RWY. THERE WERE NO INJURIES OR DAMAGE TO THE ACFT.

Narrative

AFTER BEING CLRED FOR THE ILS RWY 12 APCH BY ZLC; WE PROCEEDED TO THE BZN VOR AND BEGAN TO FLY THE CHARTED APCH PROC. CONTACTED BZN RADIO AND WAS TOLD TO RPT 'MANNI' INBOUND. COMPLETED CHKLISTS -- CALLED 'MANNI' INBOUND TO RWY 12. SAW RWY ENVIRONMENT AT ABOUT 400 FT AGL. RWY APPEARED TO BE COVERED IN HARD PACKED SNOW. DID NOT SEE VASI. MADE ALL REQUIRED COMPANY CALLOUTS ON FINAL. CAPT STATED HIS INTENTION TO LAND. CAPT MADE SMOOTH LNDG AND SELECTED REVERSE THRUST AND BRAKES WHICH APPEARED TO BE NOT VERY EFFECTIVE. CAPT THEN SELECTED FULL REVERSE AND BRAKES BEING CAREFUL TO AVOID ASYMMETRY. ANTI-SKID WAS CYCLING NORMALLY. ACFT DECELERATED VERY SLOWLY. I CALLED OUT 100 KTS; 80 KTS; 60 KTS. STARTED TO GET COMPRESSOR STALLS. BECAME APPARENT THAT WE WERE NOT GOING TO STOP BY THE END OF THE RWY. EXITED THE END OF THE RWY INTO HARD-PACKED DIRT AND SNOW STILL IN FULL REVERSE AND FULL BRAKES. ACFT CAME TO REST APPROX 50 FT BEYOND END OF RWY 12. CAPT THEN SELECTED IDLE THRUST. CAPT NOTIFIED PAX VIA PA TO REMAIN SEATED. I NOTIFIED BZN FSS OF OUR POS AND REQUESTED EQUIP TO MEET ACFT. CAPT TOLD BZN RADIO OF OUR INABILITY TO STOP AND SUGGESTED THAT OPS BE SUSPENDED AT BZN ARPT. WE COMPLETED PARKING AND SECURING CHKLISTS -- SHUT ENGS DOWN PUT APU PWR ON ACFT. NO INJURIES TO PAY OR CREW. NO APPARENT DAMAGE TO ACFT. PAX EXITED VIA FORWARD AIRSTAIRS INTO VANS AND WERE BUSSED TO TERMINAL. ACFT TOWED BACK ONTO RWY LATER THAT DAY. WE STARTED ENGS AND TAXIED TO GATE.