Narrative:

During before starting engines checklist, 10000 ft was entered into the digital flight guidance panel per the pre departure clearance. During chkin with departure control, altitude set was confirmed to be 10000 ft. At 10200 ft, departure control cleared us to 17000 ft, and when the PNF started to dial that into the flight guidance panel, we were both surprised to find that 12000 ft was set into it. Neither of us could remember entering that altitude, and we confirmed with departure control that we were never cleared to 12000 ft. After reviewing the course of events up to that point, neither of us could recall a time when either of us might have bumped the altitude set knob, and decided that it could have been a malfunction of the flight guidance panel, which was subsequently written up in the log. Even though a malfunction may have caused the set altitude to change, we should have been more vigilant in remaining alert to what the assigned altitude really was in order to prevent a malfunction or anything else from causing an altitude bust.

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Original NASA ASRS Text

Title: MD80 CREW OVERSHOOTS ALT ASSIGNED AS CTLR GIVES NEW CLB CLRNC. THEY FIND THEIR ALT ALERTER SET TO WRONG ALT.

Narrative: DURING BEFORE STARTING ENGS CHKLIST, 10000 FT WAS ENTERED INTO THE DIGITAL FLT GUIDANCE PANEL PER THE PDC. DURING CHKIN WITH DEP CTL, ALT SET WAS CONFIRMED TO BE 10000 FT. AT 10200 FT, DEP CTL CLRED US TO 17000 FT, AND WHEN THE PNF STARTED TO DIAL THAT INTO THE FLT GUIDANCE PANEL, WE WERE BOTH SURPRISED TO FIND THAT 12000 FT WAS SET INTO IT. NEITHER OF US COULD REMEMBER ENTERING THAT ALT, AND WE CONFIRMED WITH DEP CTL THAT WE WERE NEVER CLRED TO 12000 FT. AFTER REVIEWING THE COURSE OF EVENTS UP TO THAT POINT, NEITHER OF US COULD RECALL A TIME WHEN EITHER OF US MIGHT HAVE BUMPED THE ALT SET KNOB, AND DECIDED THAT IT COULD HAVE BEEN A MALFUNCTION OF THE FLT GUIDANCE PANEL, WHICH WAS SUBSEQUENTLY WRITTEN UP IN THE LOG. EVEN THOUGH A MALFUNCTION MAY HAVE CAUSED THE SET ALT TO CHANGE, WE SHOULD HAVE BEEN MORE VIGILANT IN REMAINING ALERT TO WHAT THE ASSIGNED ALT REALLY WAS IN ORDER TO PREVENT A MALFUNCTION OR ANYTHING ELSE FROM CAUSING AN ALT BUST.

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.