FLC OF ACR MLG ACFT LANDED WITHOUT CLRNC.

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CAVU DAY. APCH CTL TURNED ACFT ONTO FINAL AT OM AND REQUESTED SWITCH TWR ON 131.7 OM IS ARLIG AT 5.6 MI. FO WAS FLYING AND CAPT SWITCHED FREQ AND CALLED ARLIG FOR 10R. IN THE SEQUENCE OF PREPARING THE ACFT FOR LNDG AND COMPLETING THE BEFORE LNDG CHKLIST; I HONESTLY DO NOT RECALL IF WE RECEIVED A RESPONSE. WE LANDED ON 10R AND WHEN CONTACTING GND WERE INFORMED WE HAD LANDED WITHOUT A CLRNC. THE RADIO WAS SHOWING 131.67 AT THAT TIME AND EITHER HAD ALWAYS BEEN THERE SINCE LEAVING APCH CTL OR HAD BEEN INADVERTENTLY NUDGED OFF THE FREQ. ONCE CHOCKED; I TELEPHONED THE TWR AND THEIR PRIMARY CONCERN WAS THAT AN ACFT WAS LNDG ON AN INTERSECTING RWY (RWY 05 -- 10;500 FT DOWN RWY 10R AND WELL BEYOND OUR LNDG ROLLOUT) AND THEY WERE UNABLE TO TELL US NOT TO ROLL OUT TO END BUT HAD CONTACTED THE OTHER ACFT AND RECEIVED HIS ASSURANCE HE WOULD HOLD SHORT OF RWY 10R. THE ONLY CONTRIBUTING FACTOR TO BOTH OF US NOT REALIZING WE HADN'T RECEIVED A LNDG CLRNC OTHER THAN THE SUPERB VISIBILITY WAS FLYING AFTERNOON AND EVENING FOR 3 DAYS FOLLOWED BY AN EARLY GET-UP ON THE FOURTH DAY AND A LAYOVER AT A FAIRLY NOISY ARPT MOTEL.