ACR PLT MISSED A TURN ON A PUBLISHED ARR.

Narrative

WE WERE AT FL350 ENRTE TO MEM ARRIVING FROM THE W. ZME COULD NOT CLR OUR FIRST REQUEST FOR DSCNT; PROBABLY DUE TO A CONFLICT IN TFC. SOON AFTER THIS THERE WAS ANOTHER REQUEST BY US AND WE WERE CLRED FOR THE DSCNT AND ARR. THIS PLACED US ABOUT 20 NM INSIDE OUR CALCULATED DSCNT POINT. STRONG WESTERLY WINDS (238 DEGS AT 87 KTS) DICTATED AN EARLY DSCNT. AFTER WE BEGAN THE ARR; PF (CAPT) INCREASED SPD TO 320 KIAS AND THIS HELPED THE DSCNT PROFILE. AS WE NEARED THE 35 DME MARK FROM THE MEM VOR; THE PF SWITCHED FROM OMEGA NAV TO VOR TRACKING USING THE AUTOPLT. AT THIS POINT THE PNF (FO) WENT ABOUT TUNING AND IDENTING THE NAVAIDS CURRENTLY BEING USED AND ANTICIPATED FOR THE SOUTHERLY LNDG ON RWY 18L. DURING THIS TIME WE WERE SWITCHED FROM ZME TO MEM APCH. FURTHER DSCNT TO 4000 FT MSL WAS CLRED. THERE WAS SOME INDECISION FROM MEM APCH AS TO HOW FAR TO DSND US AT THIS POINT. MEM APCH INITIALLY SAID 6000 FT MSL THEN RECLRED US TO 4000 FT MSL. AFTER THIS WAS STRAIGHTENED OUT WE WERE ASKED OUR HDG AND REPLIED NEBOUND ON THE ARR. MEM APCH THEN HAD US FLY A 360 DEG HDG. I HONESTLY DO NOT REMEMBER WHAT THE DME READ AT THIS POINT. APPARENTLY WE HAD MISSED THE 8 DME TURN TO 355 DEG HDG. THE PF HAD THE AUTOPLT RESTR TO 15 DEGS ANGLE OF BANK FROM THE ENRTE PHASE OF FLT AND THIS MADE THE RATE OF OUR TURN INITIALLY SLOW. AS WE WERE PASSING 360 DEGS AND 6000 FT MSL; PF INCREASED TO 25 DEGS ANGLE OF BANK AND A FURTHER TURN TO 330 DEGS WAS ASSIGNED. WE WERE TURNED IN BEHIND A DC-9 AND SWITCHED TO MEM TWR. I WAS SURPRISED TO FIND THAT IT WAS THE SAME MEM APCH CTLR'S VOICE. AS WE BROKE OUT FROM THE LOWEST CLOUD LAYER MEM TWR ASKED US FOR OUR LNDG LIGHTS ON AND WE COMPLIED. THE REST OF THE LAND WAS UNEVENTFUL. THE NEXT AFTERNOON WHEN WE SIGNED IN; THE CAPT HAD A NOTE GIVEN TO HIM ASKING HIM TO CALL THE LCL ATC SUPVR. I WAS NOT PRIVY TO THIS CONVERSATION BUT; WHEN ASKED LATER; THE CAPT SAID THAT 'IT IS ALL TAKEN CARE OF. THIS IS NOT A PROB.' I DO NOT KNOW FOR SURE WHAT HE MEANT BY THIS. I THINK THAT THE CAUSE FOR THIS MISSED TURN STARTED BACK AT THE DSCNT POINT. IT WAS LATE AND PUSHED US TO MAKE THE ALTS REQUIRED FOR THE ARR. THE PF HAD BEEN ON VACATION FOR THE PERIOD IMMEDIATELY PRECEDING THIS FLT AND I COULD HAVE BACKED HIM UP BETTER AS THE PNF. I PERCEIVED A CONTRIBUTING FACTOR COULD BE THE INCREASED WORKLOAD THE CTLR HAD WITH BOTH THE ARRIVING RADAR AND LCL TWR GND CTL TFC.