Narrative:

Approaching anc at 35000 ft, descent was initiated by ATC approximately 120 DME southeast of anc. Through several stepdowns we were ultimately cleared to 10000 ft. Passing 18000 ft 'approach check' was called for and accomplished to 'the line.' toward the last part of the checklist, ATC called with another stepdown and broke the continuity of the checklist which broke the instinctive 'flow' which would have included the altimeter at that point. We continued descent toward 10000 ft, when at approximately 10500 ft my first officer realized the altimeters had not been reset and called it to my attention. Level off was initiated, altimeters reset and climbed back to 10000 ft. The altimeter in anc was 28.66 at the time and could have resulted in an excursion of nearly 1300 ft. We actually went down to about 9400 ft momentarily. An alert ATC controller caught the excursion about the same time as the first officer called out the altimeter setting. This incident has several contributing factors such as: fatigue, since the crew had been up most of the night and in the air for nearly 7 hours, the communication interruption which broke the 'old habits,' but primarily the change in the checklist and operating procedures which were received by the crew at check in for this flight. The operating revision was in the neighborhood of 100 pages with a change in the checklist which involved a complete change of checklist philosophy in the 'approach check' portion of the document. The new checklist placed 'altimeters' below the line which is a part of the checklist traditionally completed when cleared for the approach and set up for the approach. The new checklist used 'the line' to differentiate between items on the checklist completed out of 18000 ft and the altimeter setting which in international operations aren't necessarily reset at 18000 ft.

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Original NASA ASRS Text

Title: FLC OF WDB ACR ACFT FAILED TO RESET ALTIMETER DURING DSCNT RESULTING IN OVERSHOOT OF ASSIGNED ALT.

Narrative: APCHING ANC AT 35000 FT, DSCNT WAS INITIATED BY ATC APPROX 120 DME SE OF ANC. THROUGH SEVERAL STEPDOWNS WE WERE ULTIMATELY CLRED TO 10000 FT. PASSING 18000 FT 'APCH CHK' WAS CALLED FOR AND ACCOMPLISHED TO 'THE LINE.' TOWARD THE LAST PART OF THE CHKLIST, ATC CALLED WITH ANOTHER STEPDOWN AND BROKE THE CONTINUITY OF THE CHKLIST WHICH BROKE THE INSTINCTIVE 'FLOW' WHICH WOULD HAVE INCLUDED THE ALTIMETER AT THAT POINT. WE CONTINUED DSCNT TOWARD 10000 FT, WHEN AT APPROX 10500 FT MY FO REALIZED THE ALTIMETERS HAD NOT BEEN RESET AND CALLED IT TO MY ATTN. LEVEL OFF WAS INITIATED, ALTIMETERS RESET AND CLBED BACK TO 10000 FT. THE ALTIMETER IN ANC WAS 28.66 AT THE TIME AND COULD HAVE RESULTED IN AN EXCURSION OF NEARLY 1300 FT. WE ACTUALLY WENT DOWN TO ABOUT 9400 FT MOMENTARILY. AN ALERT ATC CTLR CAUGHT THE EXCURSION ABOUT THE SAME TIME AS THE FO CALLED OUT THE ALTIMETER SETTING. THIS INCIDENT HAS SEVERAL CONTRIBUTING FACTORS SUCH AS: FATIGUE, SINCE THE CREW HAD BEEN UP MOST OF THE NIGHT AND IN THE AIR FOR NEARLY 7 HRS, THE COM INTERRUPTION WHICH BROKE THE 'OLD HABITS,' BUT PRIMARILY THE CHANGE IN THE CHKLIST AND OPERATING PROCS WHICH WERE RECEIVED BY THE CREW AT CHK IN FOR THIS FLT. THE OPERATING REVISION WAS IN THE NEIGHBORHOOD OF 100 PAGES WITH A CHANGE IN THE CHKLIST WHICH INVOLVED A COMPLETE CHANGE OF CHKLIST PHILOSOPHY IN THE 'APCH CHK' PORTION OF THE DOCUMENT. THE NEW CHKLIST PLACED 'ALTIMETERS' BELOW THE LINE WHICH IS A PART OF THE CHKLIST TRADITIONALLY COMPLETED WHEN CLRED FOR THE APCH AND SET UP FOR THE APCH. THE NEW CHKLIST USED 'THE LINE' TO DIFFERENTIATE BTWN ITEMS ON THE CHKLIST COMPLETED OUT OF 18000 FT AND THE ALTIMETER SETTING WHICH IN INTL OPS AREN'T NECESSARILY RESET AT 18000 FT.

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.