Narrative:

Descending into hkg, we were cleared to 4100 ft on a vector for the ILS runway 7L. This flight is notorious for fatigue due to reversed sleep cycle. We also had a problem with the cabin to cockpit interphone where the flight attendants would try to call the cockpit, and we would get multiple dings, but were not able to talk to them. This eventually led to 3 different flight attendants coming to the door to see what was wrong, and I had to keep getting up to open the door. We were both fighting to keep our eyes open during the initial part of the descent, and after leveling at fl 110 (transition altitude) we drove in for several mins. I wanted to give the prep for landing call as soon as we left that altitude, and was wondering if they would even hear it. Then we were told to descend to 4100 ft. The copilot set his altimeter, while I made the prep for landing PA, and when done, I was distraction by additional calls from approach control and forgot to set mine. The first officer was flying on autoplt, and when the aircraft descended through 4100 ft and leveled at 3900 ft, he caught it and was trying to get it back to 4100 ft. As soon as he said 'it isn't leveling,' I knew why, and hit my altimeter button, and he hit flight level change to get us back. Approach called and reminded us of the altitude, and gave us the altimeter setting again. There were several distrs here, but the fatigue was the biggest factor in this.

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Original NASA ASRS Text

Title: FLT CREW OF B744 DSNDED BELOW CLRED ALT AT VHHH WHEN CAPT FAILED TO CHANGE FROM QNE TO QNH AT TRANSITION ALT. CREW FATIGUE DUE TO BACK SIDE OF CLOCK OP AND DISTR DUE TO INOP INTERPHONE CONTRIBUTED.

Narrative: DSNDING INTO HKG, WE WERE CLRED TO 4100 FT ON A VECTOR FOR THE ILS RWY 7L. THIS FLT IS NOTORIOUS FOR FATIGUE DUE TO REVERSED SLEEP CYCLE. WE ALSO HAD A PROB WITH THE CABIN TO COCKPIT INTERPHONE WHERE THE FLT ATTENDANTS WOULD TRY TO CALL THE COCKPIT, AND WE WOULD GET MULTIPLE DINGS, BUT WERE NOT ABLE TO TALK TO THEM. THIS EVENTUALLY LED TO 3 DIFFERENT FLT ATTENDANTS COMING TO THE DOOR TO SEE WHAT WAS WRONG, AND I HAD TO KEEP GETTING UP TO OPEN THE DOOR. WE WERE BOTH FIGHTING TO KEEP OUR EYES OPEN DURING THE INITIAL PART OF THE DSCNT, AND AFTER LEVELING AT FL 110 (TRANSITION ALT) WE DROVE IN FOR SEVERAL MINS. I WANTED TO GIVE THE PREP FOR LNDG CALL AS SOON AS WE LEFT THAT ALT, AND WAS WONDERING IF THEY WOULD EVEN HEAR IT. THEN WE WERE TOLD TO DSND TO 4100 FT. THE COPLT SET HIS ALTIMETER, WHILE I MADE THE PREP FOR LNDG PA, AND WHEN DONE, I WAS DISTR BY ADDITIONAL CALLS FROM APCH CTL AND FORGOT TO SET MINE. THE FO WAS FLYING ON AUTOPLT, AND WHEN THE ACFT DSNDED THROUGH 4100 FT AND LEVELED AT 3900 FT, HE CAUGHT IT AND WAS TRYING TO GET IT BACK TO 4100 FT. AS SOON AS HE SAID 'IT ISN'T LEVELING,' I KNEW WHY, AND HIT MY ALTIMETER BUTTON, AND HE HIT FLT LEVEL CHANGE TO GET US BACK. APCH CALLED AND REMINDED US OF THE ALT, AND GAVE US THE ALTIMETER SETTING AGAIN. THERE WERE SEVERAL DISTRS HERE, BUT THE FATIGUE WAS THE BIGGEST FACTOR IN THIS.

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.