Narrative:

On a flight from iah to hrl at cruise flight of FL180, we were advised by ATC that FL180 would be unusable. We were then assigned FL200. Upon setting up the FMS, I neglected to dial in the newly assigned altitude. Passing through FL204, ATC asked our altitude, in which I responded that I was leveling at FL200. She had advised me that my altitude readout was FL204. I thanked her and advised her we were level at FL200 after returning to it.

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Original NASA ASRS Text

Title: ATR 42 IAH TO HRL MAINTAINING FL180. CLRED TO CLB AND MAINTAIN FL200. CAPT FAILED TO SET ALT IN FMS. CTLR CALLED AS THE ACFT WAS LEAVING FL204. RETURNED TO FL200.

Narrative: ON A FLT FROM IAH TO HRL AT CRUISE FLT OF FL180, WE WERE ADVISED BY ATC THAT FL180 WOULD BE UNUSABLE. WE WERE THEN ASSIGNED FL200. UPON SETTING UP THE FMS, I NEGLECTED TO DIAL IN THE NEWLY ASSIGNED ALT. PASSING THROUGH FL204, ATC ASKED OUR ALT, IN WHICH I RESPONDED THAT I WAS LEVELING AT FL200. SHE HAD ADVISED ME THAT MY ALT READOUT WAS FL204. I THANKED HER AND ADVISED HER WE WERE LEVEL AT FL200 AFTER RETURNING TO IT.

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.