Narrative:

We were climbing from FL310 to FL330 behind traffic ahead at FL350. Traffic on same track. We had slowed to gain spacing and when we were at FL310 the controller said as soon as we picked up spacing we would be cleared to requested altitude. When we cleared out of FL310, I interpreted the clearance incorrectly as FL350 instead of FL330. The aircraft climbed to 33500 ft when we caught my error and descended to FL330. Supplemental information from acn 250676: first officer thought we were cleared to FL350 and climbed through FL330. He was watching aircraft in front of us, which was also on TCASII.

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Original NASA ASRS Text

Title: AN ACR LGT CLBED THROUGH ITS ASSIGNED ALT.

Narrative: WE WERE CLBING FROM FL310 TO FL330 BEHIND TFC AHEAD AT FL350. TFC ON SAME TRACK. WE HAD SLOWED TO GAIN SPACING AND WHEN WE WERE AT FL310 THE CTLR SAID AS SOON AS WE PICKED UP SPACING WE WOULD BE CLRED TO REQUESTED ALT. WHEN WE CLRED OUT OF FL310, I INTERPRETED THE CLRNC INCORRECTLY AS FL350 INSTEAD OF FL330. THE ACFT CLBED TO 33500 FT WHEN WE CAUGHT MY ERROR AND DSNDED TO FL330. SUPPLEMENTAL INFO FROM ACN 250676: FO THOUGHT WE WERE CLRED TO FL350 AND CLBED THROUGH FL330. HE WAS WATCHING ACFT IN FRONT OF US, WHICH WAS ALSO ON TCASII.

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.