Narrative:

I understood that we were cleared to descend to FL230. I dialed in FL230 in the altitude selector. The controller came back after we leveled at FL230 and asked us our altitude. We responded FL230. She said that we had been cleared to descend to FL240. She asked us to climb back to FL240, which we did. I thought that I read back to her FL230 in the initial clearance. I may have misunderstood.

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Original NASA ASRS Text

Title: ZDC CTLR ALERTS C560 FLC OF ALT OVERSHOOT.

Narrative: I UNDERSTOOD THAT WE WERE CLRED TO DSND TO FL230. I DIALED IN FL230 IN THE ALT SELECTOR. THE CTLR CAME BACK AFTER WE LEVELED AT FL230 AND ASKED US OUR ALT. WE RESPONDED FL230. SHE SAID THAT WE HAD BEEN CLRED TO DSND TO FL240. SHE ASKED US TO CLB BACK TO FL240, WHICH WE DID. I THOUGHT THAT I READ BACK TO HER FL230 IN THE INITIAL CLRNC. I MAY HAVE MISUNDERSTOOD.

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.