Narrative:

En route, approximately 20 mi north of memphis, received clearance to go to '350' then direct stl. Interpreted clearance to climb to FL350 when controller meant a heading of 350 degrees. Out of FL334, the controller queried as to why we were off our assigned altitude of FL330. We returned to FL330 without further incident or apparent traffic conflict.

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Original NASA ASRS Text

Title: AN MD80 CAPT MISTOOK A HDG ASSIGNMENT FOR AN ALT ASSIGNMENT, CAUSING AN ALT OVERSHOOT WITH ZME.

Narrative: ENRTE, APPROX 20 MI N OF MEMPHIS, RECEIVED CLRNC TO GO TO '350' THEN DIRECT STL. INTERPED CLRNC TO CLB TO FL350 WHEN CTLR MEANT A HDG OF 350 DEGS. OUT OF FL334, THE CTLR QUERIED AS TO WHY WE WERE OFF OUR ASSIGNED ALT OF FL330. WE RETURNED TO FL330 WITHOUT FURTHER INCIDENT OR APPARENT TFC CONFLICT.

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.