Narrative:

We were deviating around multiple cloud build-ups with the ok from ZLC. After getting clear of all clouds; ZLC asked us to confirm level at FL340. We then noticed our altitude was 400+ ft high. We immediately corrected to FL340.

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Original NASA ASRS Text

Title: MD10 FLT CREW HAS AN ALTDEV WHILE ENRTE.

Narrative: WE WERE DEVIATING AROUND MULTIPLE CLOUD BUILD-UPS WITH THE OK FROM ZLC. AFTER GETTING CLR OF ALL CLOUDS; ZLC ASKED US TO CONFIRM LEVEL AT FL340. WE THEN NOTICED OUR ALT WAS 400+ FT HIGH. WE IMMEDIATELY CORRECTED TO FL340.

Data retrieved from NASA's ASRS site as of January 2009 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.