CRJ200 FLT CREW EXECUTES GAR WHEN GPWS ALERTS THEM TO IMPROPER ACFT CONFIGN.

Narrative

DURING APCH TO RWY 18C; THE FO (WHO WAS FLYING) CALLED FOR FLAPS 45 DEGS AND BEFORE LNDG CHKLIST. THE CHKLIST WAS VERBALIZED AS REQUIRED; BUT THE FLAPS WERE STILL AT 30 DEGS EXTENSION. NEITHER OF US CAUGHT THE FACT THAT THE FLAPS WERE AT THE WRONG SETTING. ON SHORT FINAL THE GPWS ANNUNCIATED; 'TOO LOW FLAPS' AND WE DECIDED THAT THE BEST COURSE OF ACTION WAS TO GO AROUND. AS IT WAS MY JOB AS THE PNF TO PUT THE FLAPS DOWN; I WAS CERTAIN I HAD DONE SO. IT IS QUITE POSSIBLE THAT I STARTED TO AND GOT DISTR. AS FOR COMPLETING THE BEFORE LNDG CHKLIST; WE DID VERBALIZE IT USING CHALLENGE AND RESPONSE; BUT I THINK WE JUST SAW WHAT WE WANTED/EXPECTED TO SEE. A CONTRIBUTING FACTOR TO THIS EVENT WAS BEING TIRED. THIS TRIP HAD 3 CONSECUTIVE EARLY RPTS; INCLUDING AN XA45 WAKE-UP ON DAY #2; XB15 ON THE EVENT DATE. ON TOP OF THAT; THE EVENT DATE ALSO INCLUDED 2 LONG BREAKS; INCLUDING 1 BEFORE THE FLT AND 1 WE WERE ANTICIPATING AFTER THE FLT. IN SHORT; WE WERE SORT OF ROBOTIC AND TIRED; AND WE WANTED TO FINISH THE DAY. SUPPLEMENTAL INFO FRO ACN 687663: I EVEN CALLED SCHEDULING AND SPOKE TO A SUPVR AT XA45 AND AGAIN AT XB30 ASKING HIM TO TAKE ME OFF THE REST OF THE TRIP BECAUSE I WAS SO EXHAUSTED. HE TRIED TO WORK THAT OUT; BUT SAID WE WERE SHORT STAFFED. I TOLD HIM I WASN'T GOING TO CALL IN SICK (BECAUSE I WASN'T SICK) AND I TOLD HIM THAT I WOULDN'T CALL IN FATIGUED BECAUSE THEY DIDN'T HAVE THE STAFFING. ALL OF MY TRIPS DURING THE MONTH HAD MUCH LATER RPT TIMES; SO I WASN'T USED TO GETTING UP SO EARLY AND WASN'T ABLE TO FALL ASLEEP EARLY. IN HINDSIGHT; I FEEL THAT I SHOULD HAVE CALLED IN FATIGUED INSTEAD OF FIGHTING THE EXHAUSTION.