Narrative:

While climbing to FL270 I was told as I was going through FL250 that my assigned altitude was FL250. We hurried back down to FL250 and min later an aircraft passed over at FL270. I believe that we were assigned FL270 originally and that the controller was in error. There was no close call, but may have been if we did not catch it when we did. I have the PNF always read back an altitude that was assigned, and I will emphasize this from now on.

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Original NASA ASRS Text

Title: AN EMB145 FLT CREW, PASSING FL250, IS ADVISED BY ZHU THAT THEY WERE SUPPOSED TO LEVEL OFF AT FL250. THE FLT CREW THOUGHT THEY WERE CLRED TO FL270.

Narrative: WHILE CLBING TO FL270 I WAS TOLD AS I WAS GOING THROUGH FL250 THAT MY ASSIGNED ALT WAS FL250. WE HURRIED BACK DOWN TO FL250 AND MIN LATER AN ACFT PASSED OVER AT FL270. I BELIEVE THAT WE WERE ASSIGNED FL270 ORIGINALLY AND THAT THE CTLR WAS IN ERROR. THERE WAS NO CLOSE CALL, BUT MAY HAVE BEEN IF WE DID NOT CATCH IT WHEN WE DID. I HAVE THE PNF ALWAYS READ BACK AN ALT THAT WAS ASSIGNED, AND I WILL EMPHASIZE THIS FROM NOW ON.

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.