Narrative:

While on the published profile descent into den, we received abnormal crossing points with abnormal crossing altitude restrictions. When accomplishing the in-range checklist descending through FL180, I stated an altimeter setting of 29.64 derived from the den ATIS. My first officer stated the current setting was 29.66, but he inadvertently set 30.66 instead. Our clearance was to descend to cross 10 DME from den at 13000', but due to the incorrect altitude setting we inadvertently descended below 13000'. The error was noticed nearly simultaneously by ATC, the altitude reminder on the aircraft and by visibility reference to my altimeter. We correct immediately back to 13000' and rest the first officer altimeter to 29.66. I honestly do not remember whether I called the '1000' above level-off' reminder. If I did, it was apparently suppressed by ATC radio traffic or by cockpit activities. I feel the major contributing factors was the interruption of the normal profile descent requiring the compressed recomputation of descent rates and speeds during the time when the in-range checklist, which includes the setting of all altimeters, was being accomplished. A contributing factor was the profuse radio traffic, TCASII advisory being activated (not a result of the altitude deviation) and our communication and concern over a low level wind shear alert advisory with microburst alert.

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Original NASA ASRS Text

Title: ACR MLG ALT OVERSHOT IN DESCENT INTO DEN.

Narrative: WHILE ON THE PUBLISHED PROFILE DSNT INTO DEN, WE RECEIVED ABNORMAL XING POINTS WITH ABNORMAL XING ALT RESTRICTIONS. WHEN ACCOMPLISHING THE IN-RANGE CHKLIST DSNDING THROUGH FL180, I STATED AN ALTIMETER SETTING OF 29.64 DERIVED FROM THE DEN ATIS. MY F/O STATED THE CURRENT SETTING WAS 29.66, BUT HE INADVERTENTLY SET 30.66 INSTEAD. OUR CLRNC WAS TO DSND TO CROSS 10 DME FROM DEN AT 13000', BUT DUE TO THE INCORRECT ALT SETTING WE INADVERTENTLY DSNDED BELOW 13000'. THE ERROR WAS NOTICED NEARLY SIMULTANEOUSLY BY ATC, THE ALT REMINDER ON THE ACFT AND BY VIS REF TO MY ALTIMETER. WE CORRECT IMMEDIATELY BACK TO 13000' AND REST THE F/O ALTIMETER TO 29.66. I HONESTLY DO NOT REMEMBER WHETHER I CALLED THE '1000' ABOVE LEVEL-OFF' REMINDER. IF I DID, IT WAS APPARENTLY SUPPRESSED BY ATC RADIO TFC OR BY COCKPIT ACTIVITIES. I FEEL THE MAJOR CONTRIBUTING FACTORS WAS THE INTERRUPTION OF THE NORMAL PROFILE DSNT REQUIRING THE COMPRESSED RECOMPUTATION OF DSNT RATES AND SPDS DURING THE TIME WHEN THE IN-RANGE CHKLIST, WHICH INCLUDES THE SETTING OF ALL ALTIMETERS, WAS BEING ACCOMPLISHED. A CONTRIBUTING FACTOR WAS THE PROFUSE RADIO TFC, TCASII ADVISORY BEING ACTIVATED (NOT A RESULT OF THE ALT DEVIATION) AND OUR COM AND CONCERN OVER A LOW LEVEL WIND SHEAR ALERT ADVISORY WITH MICROBURST ALERT.

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.