Narrative:

We were on a visual approach to runway 18R in cvg in severe clear WX. It was my leg. I disconnected the autoplt at about 4 mi; approximately over or before reaching the ohio river. I trimmed the aircraft up and to my knowledge did not touch the trim again for the rest of the approach; as I always do on such approachs. Upon entering the flare or slightly before it; the clacker for the trim sounded; signifying a trim input (I believe it should sound only if the input is for more than 3 seconds). I looked at the trim indication and saw it was increasing. My finger was not on the trim switch. Since we were in the flare I thought it prudent to simply land. Before we touched down the trim stopped at a setting of 8.4. Upon taxiing in I told the captain that I did not trim the aircraft during the flare. He thought it prudent; and I agreed; to write up the event in the maintenance log. As stated before I am not in the habit of trimming during the flare. Is it within the realm of possibility that I hit the trim switch? Possibly; but I have never had the trim setting up at 8.4 before; intentionally or otherwise and don't know anyone else who does either. The captain and I had 10 other legs on that trip on other aircraft and never had that happen on any of them. Being in the flare when it happened it seemed safer to land the aircraft rather than try to reject the landing with a possible pitch trim runaway. If there were a specific setting we were taught to set for pitch trim on landing; perhaps I would have been more aware if I or the airplane were giving inputs that were deviating from that setting.

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Original NASA ASRS Text

Title: CRJ200 HAS STABILIZER TRIM MALFUNCTION DURING APCH AND LNDG AT CVG.

Narrative: WE WERE ON A VISUAL APCH TO RWY 18R IN CVG IN SEVERE CLR WX. IT WAS MY LEG. I DISCONNECTED THE AUTOPLT AT ABOUT 4 MI; APPROX OVER OR BEFORE REACHING THE OHIO RIVER. I TRIMMED THE ACFT UP AND TO MY KNOWLEDGE DID NOT TOUCH THE TRIM AGAIN FOR THE REST OF THE APCH; AS I ALWAYS DO ON SUCH APCHS. UPON ENTERING THE FLARE OR SLIGHTLY BEFORE IT; THE CLACKER FOR THE TRIM SOUNDED; SIGNIFYING A TRIM INPUT (I BELIEVE IT SHOULD SOUND ONLY IF THE INPUT IS FOR MORE THAN 3 SECONDS). I LOOKED AT THE TRIM INDICATION AND SAW IT WAS INCREASING. MY FINGER WAS NOT ON THE TRIM SWITCH. SINCE WE WERE IN THE FLARE I THOUGHT IT PRUDENT TO SIMPLY LAND. BEFORE WE TOUCHED DOWN THE TRIM STOPPED AT A SETTING OF 8.4. UPON TAXIING IN I TOLD THE CAPT THAT I DID NOT TRIM THE ACFT DURING THE FLARE. HE THOUGHT IT PRUDENT; AND I AGREED; TO WRITE UP THE EVENT IN THE MAINT LOG. AS STATED BEFORE I AM NOT IN THE HABIT OF TRIMMING DURING THE FLARE. IS IT WITHIN THE REALM OF POSSIBILITY THAT I HIT THE TRIM SWITCH? POSSIBLY; BUT I HAVE NEVER HAD THE TRIM SETTING UP AT 8.4 BEFORE; INTENTIONALLY OR OTHERWISE AND DON'T KNOW ANYONE ELSE WHO DOES EITHER. THE CAPT AND I HAD 10 OTHER LEGS ON THAT TRIP ON OTHER ACFT AND NEVER HAD THAT HAPPEN ON ANY OF THEM. BEING IN THE FLARE WHEN IT HAPPENED IT SEEMED SAFER TO LAND THE ACFT RATHER THAN TRY TO REJECT THE LNDG WITH A POSSIBLE PITCH TRIM RUNAWAY. IF THERE WERE A SPECIFIC SETTING WE WERE TAUGHT TO SET FOR PITCH TRIM ON LNDG; PERHAPS I WOULD HAVE BEEN MORE AWARE IF I OR THE AIRPLANE WERE GIVING INPUTS THAT WERE DEVIATING FROM THAT SETTING.

Data retrieved from NASA's ASRS site as of January 2009 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.