AN ACR FLC FLYING B737-300 INTO IAH BECOMES DISTR DURING THE DSCNT RESULTING IN A FAILURE TO EXECUTE THE CLRED ARR AND PUBLISHED ALTS.

Narrative

JUST PRIOR TO STARTING THE DSCNT INTO IAH; A PAX PASSED OUT. HE APPARENTLY HAD HIGH BLOOD PRESSURE AND COLITIS AND WAS ON SOME SPECIAL MEDICATION. DURING MOST OF THE DSCNT; I WAS WORKING WITH THE CABIN CREW AND IAH OPS TO MAKE SURE THE PARAMEDICS WOULD MEET THE PLANE. WE WERE CLRED TO A COUPLE OF INTERMEDIATE ALTS THEN WE RECEIVED A CLRNC TO DSND VIA THE 'COAST II FMS ARR.' IT WAS THE FO'S LEG; SO HE SELECTED 10000 FT ON THE MCP AND STARTED THE DSCNT. WE CROSSED HOAGI AT 250 KTS AND 10000 FT. THE PLANE WAS CONNECTED TO THE AUTOPLT IN VNAV AND LNAV. THE AUTOTHROTTLES DID NOT WORK. I CHKED WITH THE CABIN AND IAH OPS ONE LAST TIME TO MAKE SURE EVERYTHING WAS READY. THEN THERE WAS A FREQ CHANGE. I READ BACK THE CORRECT FREQ BUT SELECTED A FREQ ONE DIGIT OFF. I WENT BACK TO THE PREVIOUS CTLR AND GOT THE CORRECT FREQ. PRIOR TO CHKING IN; I LOOKED TO CHK THE ACFT'S PROGRESS. THE AUTOPLT HAD BEEN DISCONNECTED AND 6000 FT (THE XING ALT AT BANTY) HAD BEEN SELECTED ON THE MCP. THIS HAD BEEN DONE PRIOR TO MACED AND A DSCNT HAD BEEN STARTED. AT 2.6 MI PRIOR TO MACED WE WERE AT 8700 FT. I IMMEDIATELY TOLD THE FO TO STOP THE DSCNT; CHKED IN WITH APCH CTL; AND ADVISED HIM OF THE SIT. WE WERE TAKEN OFF THE FMS ARR AND TOLD TO DSND TO 8000 FT. NO ALARMS WENT OFF AND IT WAS AN UNEVENTFUL LNDG. IT'S OBVIOUS THAT THIS SIT OCCURRED BECAUSE I FAILED AS THE MONITORING PLT AFTER XING HOAGI AT 250 KTS AND 10000 FT. I WANTED TO MAKE SURE EVERYTHING WAS SET FOR THE 1 PAX. DURING THIS TIME; THE AUTOPLT WAS DISCONNECTED AND A PREMATURE DSCNT WAS STARTED. WHY; I DO NOT KNOW. IN FUTURE; BELOW FL180 THERE WILL BE NO CONVERSATION WITH THE CABIN OR COMPANY. I WILL FLY THE PLANE OR BE THE MONITORING PLT ONLY.