A B737 crew received an EGPWS Obstacle warning near the OMA Runway 14L BUFFT FAF descending to 2400 ft at 600 fpm. A go around was completed followed by an uneventful approach.

Narrative

We were vectored onto the LOC for ILS Runway 14L at OMA. We were IMC at the time and I had Flaps 5 degrees and was at 180 KTS. We had been cleared to 3;000 FT to intercept the LOC then cleared for the approach. The autopilot was engaged and at LOC capture I armed the Approach Mode. The Captain asked if I wanted to go to 2;400 FT. I agreed and used the vertical speed mode to descend. I had a descent rate of about 500 FPM. We leveled off at 2;400 FT just outside BUFFT FAF; the GS was coming into view when we got an 'obstacle' warning. We got a second one and I started the go around and climb. I don't recall if we got a third warning; but I do know the 2 warnings came in rapid succession. From the first warning to the start of the go around took no more than a couple of seconds. We leveled off at 3;000 FT. The Controller was very nonchalant about our go around and seemed to indicate that he had seen this before with company aircraft. We thought that this might be a software problem. We were vectored again for the ILS Runway 14L. This time I chose to intercept the GS at 3;000 FT. This time the approach was uneventful. Check the database for the obstacles on that approach. Callback conversation with Reporter revealed the following information: The reporter determined that the 1352 FT tower near BUFFT was the obstacle seen by the EGPWS. The aircraft's rate of descent; while not unusual; was just enough to trigger the obstacle warning.