Narrative:

We were about 50 mi from our destination and descending from FL240 to 14000 ft. The assisting pilot, per the company operations manual, obtained the current ATIS at the destination and verbally related it to me. I personally advised the assisting pilot to write down the WX portion of the ATIS and place it on the center console. Crossing FL180, procedures require the PF to call out the altitude and to set the surface altimeter setting, and call for the descent checklist which is read by the assisting pilot and accomplished challenge and response. This checklist calls for the crew to reaffirm the altimeters being correctly set. When the checklist was completed, I realized there was a big difference between the ATIS altimeter setting, which is what we were using and set to, and the setting we were given when we were cleared from FL240 to 14000 ft by ATC. I questioned it by saying to the assisting pilot, 'have they had frontal passage or something?' and he replied they had. After I leveled off at 14000 ft the assisting pilot said he made a big mistake and the altimeter setting was not 29.93, as he had both told me, written, and affirmed after my questioning of it, but was actually 29.33. This put us at 13400 ft instead of 14000 ft where we belonged. I immediately climbed up to 14000 ft and soon afterwards, the approach controller handed us off to the next controller in a normal fashion without saying a word about our altitude, and neither did we. In the future, I will not question an altimeter difference in an ambiguous manner. It is smart to eliminate it in all flight operations.

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Original NASA ASRS Text

Title: AN ACR FREIGHTER CREW DSNDS THEIR MLG BELOW THE ASSIGNED ALT WHEN THEY MISSET THEIR ALTIMETERS.

Narrative: WE WERE ABOUT 50 MI FROM OUR DEST AND DSNDING FROM FL240 TO 14000 FT. THE ASSISTING PLT, PER THE COMPANY OPS MANUAL, OBTAINED THE CURRENT ATIS AT THE DEST AND VERBALLY RELATED IT TO ME. I PERSONALLY ADVISED THE ASSISTING PLT TO WRITE DOWN THE WX PORTION OF THE ATIS AND PLACE IT ON THE CTR CONSOLE. XING FL180, PROCS REQUIRE THE PF TO CALL OUT THE ALT AND TO SET THE SURFACE ALTIMETER SETTING, AND CALL FOR THE DSCNT CHKLIST WHICH IS READ BY THE ASSISTING PLT AND ACCOMPLISHED CHALLENGE AND RESPONSE. THIS CHKLIST CALLS FOR THE CREW TO REAFFIRM THE ALTIMETERS BEING CORRECTLY SET. WHEN THE CHKLIST WAS COMPLETED, I REALIZED THERE WAS A BIG DIFFERENCE BTWN THE ATIS ALTIMETER SETTING, WHICH IS WHAT WE WERE USING AND SET TO, AND THE SETTING WE WERE GIVEN WHEN WE WERE CLRED FROM FL240 TO 14000 FT BY ATC. I QUESTIONED IT BY SAYING TO THE ASSISTING PLT, 'HAVE THEY HAD FRONTAL PASSAGE OR SOMETHING?' AND HE REPLIED THEY HAD. AFTER I LEVELED OFF AT 14000 FT THE ASSISTING PLT SAID HE MADE A BIG MISTAKE AND THE ALTIMETER SETTING WAS NOT 29.93, AS HE HAD BOTH TOLD ME, WRITTEN, AND AFFIRMED AFTER MY QUESTIONING OF IT, BUT WAS ACTUALLY 29.33. THIS PUT US AT 13400 FT INSTEAD OF 14000 FT WHERE WE BELONGED. I IMMEDIATELY CLBED UP TO 14000 FT AND SOON AFTERWARDS, THE APCH CTLR HANDED US OFF TO THE NEXT CTLR IN A NORMAL FASHION WITHOUT SAYING A WORD ABOUT OUR ALT, AND NEITHER DID WE. IN THE FUTURE, I WILL NOT QUESTION AN ALTIMETER DIFFERENCE IN AN AMBIGUOUS MANNER. IT IS SMART TO ELIMINATE IT IN ALL FLT OPS.

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.