Narrative:

During descent into dfw, copilot was flying aircraft. We were cleared from 7000 ft MSL to 6000 MSL and a turn to a northeast heading for a visual approach to runway 35R. After leaving 7000 ft MSL, copilot called for approach checklist. While I was doing approach checklist, altitude alert went off. I looked up to see aircraft descending through 5700 ft MSL. Copilot leveled off and started shallow climb back to 6000 ft. At approximately 5800 ft dfw approach cleared us for the visual approach to runway 35R. No comment was made by dfw approach or by flight crew other than to acknowledge clearance for visual approach. I feel this situation could have been avoided if airline's approach checklist was made shorter and combined with other checklists, such as descent checklist or landing checklist.

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Original NASA ASRS Text

Title: A DC9-30 FLC OVERSHOT THEIR ASSIGNED ALT OF 6000 FT IN DSCNT WHILE CREW IS PERFORMING THEIR APCH CHKLIST.

Narrative: DURING DSCNT INTO DFW, COPLT WAS FLYING ACFT. WE WERE CLRED FROM 7000 FT MSL TO 6000 MSL AND A TURN TO A NE HDG FOR A VISUAL APCH TO RWY 35R. AFTER LEAVING 7000 FT MSL, COPLT CALLED FOR APCH CHKLIST. WHILE I WAS DOING APCH CHKLIST, ALT ALERT WENT OFF. I LOOKED UP TO SEE ACFT DSNDING THROUGH 5700 FT MSL. COPLT LEVELED OFF AND STARTED SHALLOW CLB BACK TO 6000 FT. AT APPROX 5800 FT DFW APCH CLRED US FOR THE VISUAL APCH TO RWY 35R. NO COMMENT WAS MADE BY DFW APCH OR BY FLC OTHER THAN TO ACKNOWLEDGE CLRNC FOR VISUAL APCH. I FEEL THIS SIT COULD HAVE BEEN AVOIDED IF AIRLINE'S APCH CHKLIST WAS MADE SHORTER AND COMBINED WITH OTHER CHKLISTS, SUCH AS DSCNT CHKLIST OR LNDG CHKLIST.

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.