Narrative:

During our macey 2 arrival into atl, our initial clearance was to cross womac at 250 KTS and 13000 ft. Subsequently, the clearance was revised to cross woman at 13000 ft and logan at 10000 ft. For still unknown reasons, the new clearance was erroneously interpreted in the cockpit to mean cross womac at or below 13000 ft to make a crossing of logan at 10000 ft. Atl approach questioned our altitude when we were approximately 4 mi short of womac descending through approximately 12500 ft. Our error quickly became obvious to us and we immediately disconnected the autoplt and expeditiously climbed back to 13000 ft. Subsequently, we did cross womac at 13000 ft and logan at 10000 ft. The remainder of the arrival was flown normally and without incident. Our lowest altitude reached during the deviation was approximately 200 ft and there was no conflict with any other aircraft as far as we know. The entire incident was most likely based upon our false assumption/interpretation of the revised clearance. A contributing factor may have been distraction and failed communication clarity as we were accomplishing the descent check at the time the revised clearance was received. Probably the best corrective action to prevent such an occurrence in the future is to pay more attention to detail, ensure full understanding of all clrncs, and question any vague areas.

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Original NASA ASRS Text

Title: AN ACR JET DSNDS PREMATURELY WHEN FLC MISINTERPS THE XING RESTRS ON THE AMENDED CLRNC INTO ATL, GA.

Narrative: DURING OUR MACEY 2 ARR INTO ATL, OUR INITIAL CLRNC WAS TO CROSS WOMAC AT 250 KTS AND 13000 FT. SUBSEQUENTLY, THE CLRNC WAS REVISED TO CROSS WOMAN AT 13000 FT AND LOGAN AT 10000 FT. FOR STILL UNKNOWN REASONS, THE NEW CLRNC WAS ERRONEOUSLY INTERPED IN THE COCKPIT TO MEAN CROSS WOMAC AT OR BELOW 13000 FT TO MAKE A XING OF LOGAN AT 10000 FT. ATL APCH QUESTIONED OUR ALT WHEN WE WERE APPROX 4 MI SHORT OF WOMAC DSNDING THROUGH APPROX 12500 FT. OUR ERROR QUICKLY BECAME OBVIOUS TO US AND WE IMMEDIATELY DISCONNECTED THE AUTOPLT AND EXPEDITIOUSLY CLBED BACK TO 13000 FT. SUBSEQUENTLY, WE DID CROSS WOMAC AT 13000 FT AND LOGAN AT 10000 FT. THE REMAINDER OF THE ARR WAS FLOWN NORMALLY AND WITHOUT INCIDENT. OUR LOWEST ALT REACHED DURING THE DEV WAS APPROX 200 FT AND THERE WAS NO CONFLICT WITH ANY OTHER ACFT AS FAR AS WE KNOW. THE ENTIRE INCIDENT WAS MOST LIKELY BASED UPON OUR FALSE ASSUMPTION/INTERP OF THE REVISED CLRNC. A CONTRIBUTING FACTOR MAY HAVE BEEN DISTR AND FAILED COM CLARITY AS WE WERE ACCOMPLISHING THE DSCNT CHK AT THE TIME THE REVISED CLRNC WAS RECEIVED. PROBABLY THE BEST CORRECTIVE ACTION TO PREVENT SUCH AN OCCURRENCE IN THE FUTURE IS TO PAY MORE ATTN TO DETAIL, ENSURE FULL UNDERSTANDING OF ALL CLRNCS, AND QUESTION ANY VAGUE AREAS.

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.