FK28 FLC MAKES LNDG WITHOUT CLRNC. IT APPEARS CTLR WAS QUITE BUSY AND MAY HAVE BEEN WORKING BOTH POS; POSSIBLY APCH CTL AS WELL.

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I WAS THE FO AND PF OF OUR 5TH LEG IN A 6 LEG DAY TRIP. WE BROKE OUT ABOUT 10 MI FROM BOI ARPT. THE CAPT TOLD APCH WE HAD THE ARPT IN SIGHT AND THE CTLR CLRED US FOR THE VISUAL TO RWY 10R; STRAIGHT-IN. THE APCH CTLR WAS BUSY WITH SEVERAL OTHER INBOUNDS. I CALLED FOR FLAPS; GEAR AND THE LNDG CHKLIST. THE CAPT COMPLETED THE CHKLIST AND ASKED FOR A 'WIND CHK.' AFTER ASKING HIM TO 'SAY AGAIN' THE CTLR GAVE US THE CURRENT WINDS. AFTER LNDG THE CAPT TOOK OVER THE AIRPLANE AT 80 KTS (STANDARD PROC) AND I ASSUMED THE PNF DUTIES. I DISCOVERED THAT THE RADIO WAS STILL ON APCH FREQ. WE BOTH ASSUMED THAT THE APCH CTLR FORGOT TO HAND US OFF TO TWR AND THAT WE HAD LANDED WITHOUT CLRNC. I SWITCHED OVER TO TWR FREQ AND ASKED THE CAPT WHAT I SHOULD SAY. HE DECIDED TO DO THE TALKING AND SAID; 'BOI TWR; ACR IDENT; UH; WE'RE HERE.' THEY RESPONDED BY CLRING US TO CROSS RWY 10L AND CALL GND ON THE OTHER SIDE. I CALLED GND AND WE WERE CLRED TO TAXI TO OUR GATE. NO MENTION WAS EVER MADE OF OUR LNDG WITHOUT CLRNC FROM THE TWR. BOI APCH; TWR AND GND ARE OFTEN COMBINED SO 1 CTLR IS WORKING ALL 3 FREQS; OR AT LEAST 2 OF THEM. I DID HAVE A MEMORY OF BEING CLRED TO LAND SO EITHER APCH WAS DOING TWR ALSO AND CLRED US TO LAND OR ELSE WE NEVER WERE CLRED AND MY MEMORY WAS INCORRECT. WE WERE BOTH UNSURE AS TO WHAT HAD TRANSPIRED. CONTRIBUTING FACTORS: PRIMARILY FATIGUE. WE'D BEEN ON DUTY FOR 9 HRS AND HAD NOT HAD A BREAK ALL DAY. THE TRIP IS SCHEDULED FOR 11 1/2 DUTY HRS AND 6.4 FLT HRS AND 6 LEGS. CONTRIBUTING TO THE CAPT'S FATIGUE WAS HE HAD JUST COMPLETED A 3 DAY TRIP WITH XA00-XB00 MORNING SHOWS. ALSO CONTRIBUTING WAS CTLR WORKLOAD AND NONSTANDARD OPS FOR THE CTLR HANDLING BOTH TWR AND APCH. THE SCHEDULES FLOWN BY REGIONAL AIRLINE PLTS -- LONG DAYS; MANY LEGS AND LIMITED DAYS OFF; ARE PART OF THE PROB. CORRECTION ACTION: IMPROVE SCHEDULING OF FLCS TO AVOID THE EARLY SHIFT THEN SWITCH TO LATE SHIFT THE NEXT DAY PROB. MORE RESEARCH INTO FATIGUE AND SLEEP PATTERN DISRUPTION. ADDING 'CLRED TO LAND' AT THE END OF THE LNDG CHKLIST WOULD HELP ALSO.