DC9 CREW LANDED AT MSP WITHOUT LNDG CLRNC.

Narrative

WE WERE CLRED FOR A VISUAL APCH FOLLOWING AN A320 TO RWY 12R AT MSP. APCH CTL CLRED US FOR A VISUAL APCH AND ALSO TO CONTACT TWR ON 5 MI FINAL. WE REALIZED UPON TOUCHDOWN THAT WE HADN'T CONTACTED TWR FOR A LNDG CLRNC. NO TFC CONFLICTS RESULTED AND WE WERE MONITORING APCH CTL FREQ DURING THE APCH AND LNDG UNTIL WE REALIZED OUR ERROR AND CHANGED TO TWR. WE ATTRIBUTE THIS ERROR PARTIALLY TO DIFFERENT PROCS USED BY DIFFERENT APCH CTLRS. CTLR A WILL HAVE YOU CONTACT TWR (IE; SWITCH NOW) AND CTLR B WILL HAVE YOU CALL TWR AT THE MARKER AND CTLR C WILL TELL YOU TO CONTACT TWR ON A 5 MI FINAL (AS OURS DID) WHEN WE WERE 13 MI OUT. THESE DIFFERENT PROCS ARE USED AT THE SAME ARPT. ALSO CONTRIBUTING TO THIS WAS STARTING OUR DAY AT XA30 AM. I THINK IT WOULD BE WISE TO STANDARDIZE ATC PROCS SUCH AS WHEN TO CONTACT TWR FOR LNDG; AND IN THE EVENT OF NO CONTACT; APCH SHOULD CONTACT THE AIRPLANE IN QUESTION; AND REMIND THEM TO CONTACT TWR. THE AIRLINE COCKPIT IS A BUSY PLACE ON FINAL APCH; (IE; CHANGES OF CONFIGN; FOLLOWING PRECEDING ACFT; RUNNING LNDG CHKLISTS; FLYING INST APCH PROCS; ETC); IT WOULD BE NICE TO HAVE APCH AS A BACKUP.