Narrative:

The day prior to this incident the flight crew had been up since XA00 at home and worked until XP40 pm (started at XB50 am). We flew 7 legs (7 hours and 40 mins). We were flying from des moines to cincinnati with 8 hours of rest. Captain was flying. On base leg for the ILS runway 36L at cincinnati, captain discovered a problem with the flight spoilers. He was distracted with that and I had the emergency checklist out in case. We were cleared for the approach. The captain did not arm the approach mode on the autoplt. He hit the navigation button. The autoplt captured the localizer but not the GS. I stated that 'the GS is below us' (we were high). The captain said 'un huh' and dialed in a steeper descent on the vertical speed mode. (This won't capture the GS.) making things worse, he had dialed a higher altitude in the autoplt (5000 ft?) for the missed so we didn't have any warning that we were going below altitude, until the plane yelled 'GS, GS.' we were at the base of the clouds at 700 ft AGL maybe 2-3 mi from the runway. We went around. We informed the flight attendant and passenger that we did a go around for traffic. We shot another ILS runway 36L. This one was uneventful. This wouldn't have happened if we hadn't been distracted and sleepy during a busy phase of flight.

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Original NASA ASRS Text

Title: GPWS BELOW GS WARNING SAVES THE DAY FOR AN ACR CREW.

Narrative: THE DAY PRIOR TO THIS INCIDENT THE FLC HAD BEEN UP SINCE XA00 AT HOME AND WORKED UNTIL XP40 PM (STARTED AT XB50 AM). WE FLEW 7 LEGS (7 HRS AND 40 MINS). WE WERE FLYING FROM DES MOINES TO CINCINNATI WITH 8 HRS OF REST. CAPT WAS FLYING. ON BASE LEG FOR THE ILS RWY 36L AT CINCINNATI, CAPT DISCOVERED A PROB WITH THE FLT SPOILERS. HE WAS DISTRACTED WITH THAT AND I HAD THE EMER CHKLIST OUT IN CASE. WE WERE CLRED FOR THE APCH. THE CAPT DID NOT ARM THE APCH MODE ON THE AUTOPLT. HE HIT THE NAV BUTTON. THE AUTOPLT CAPTURED THE LOC BUT NOT THE GS. I STATED THAT 'THE GS IS BELOW US' (WE WERE HIGH). THE CAPT SAID 'UN HUH' AND DIALED IN A STEEPER DSCNT ON THE VERT SPD MODE. (THIS WON'T CAPTURE THE GS.) MAKING THINGS WORSE, HE HAD DIALED A HIGHER ALT IN THE AUTOPLT (5000 FT?) FOR THE MISSED SO WE DIDN'T HAVE ANY WARNING THAT WE WERE GOING BELOW ALT, UNTIL THE PLANE YELLED 'GS, GS.' WE WERE AT THE BASE OF THE CLOUDS AT 700 FT AGL MAYBE 2-3 MI FROM THE RWY. WE WENT AROUND. WE INFORMED THE FLT ATTENDANT AND PAX THAT WE DID A GAR FOR TFC. WE SHOT ANOTHER ILS RWY 36L. THIS ONE WAS UNEVENTFUL. THIS WOULDN'T HAVE HAPPENED IF WE HADN'T BEEN DISTRACTED AND SLEEPY DURING A BUSY PHASE OF FLT.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.