ALTDEV ON DSCNT.

Narrative

APCHING CLT; ARPT WAS BUSY. APCH CTL HAD CHANGED ARR RWY A COUPLE OF DIFFERENT TIMES BTWN RWY 36L AND RWY 36R. WE WERE CLRED TO DSND TO 8000 FT. IN THE DSCNT; FO AND I WERE DISCUSSING WHICH RWY THEY HAD LAST TOLD US TO EXPECT. I THOUGHT IT WAS RWY 36R; HE THOUGHT RWY 36L; AND WHAT THE APPROPRIATE LOC FREQ WAS. I LOOKED OVER AT MY MANUAL FOR THE FREQ; ONLY TO FIND THE WRONG PAGE WAS DISPLAYED. AS I FLIPPED OVER FOR THE PROPER APCH PLATE; THE ALT ALERTER WENT OFF. I STOPPED THE DSCNT BY 7600 FT AND IMMEDIATELY CLBED BACK TO 8000 FT. APCH CALLED AS I BEGAN THE CLB. I DO NOT BELIEVE THIS CAUSED ANY PROB. OUR COMPANY PROC IS TO HAVE A FORMAL TRANSFER OF FLYING THE ACFT ANY TIME 1 PLT IS LOOKING AWAY; AS I WAS. I OBVIOUSLY NEGLECTED TO DO THIS; AS I ONLY EXPECTED TO LOOK AWAY FOR A SECOND. FO WAS LOOKING AT HIS APCH PLATES; TOO. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR FLIES A 'NICE LITTLE AIRPLANE; THE F-28.' IT HAS AN EARLY STYLE AUTOPLT THAT HAS NO ALT CAPTURE; BUT SO WHAT; AS THE RPTR WAS HAND FLYING THE ACFT. 'I SCREWED UP HARD; SHOULD HAVE HANDED HIM THE ACFT' PER ACR SOP. APCH CTL WAS NOT UPSET. CLT IS BAD ABOUT ASSIGNING RWYS -- CHANGING THEM SEVERAL TIMES IS NOT UNCOMMON. THE RPTR HAS NOT HEARD FROM THE FAA ON THIS INCIDENT.