Narrative:

On descent from cruise altitude of 31000 ft, both pilots discovered altimeters were never set to 29.92 during cruise at FL310. Altimeters were still set at 30.44, resulting in a 460 ft error while cruising at 31000 ft. The medium large transport has a button to push to change the altimeters from 29.92 to the local setting, instead of the usual setting knob located on the altimeter. For some reason, I find it harder to remember to change the altimeter settings while passing 18000 ft than in other aircraft. All other medium large transport pilots I've talked to also report having the same difficulty. The controller handling our flight never mentioned an altitude discrepancy, so I assume he never noticed it. It sure would enhance safety if a warning chime could be installed to go off while passing 18000 ft.

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Original NASA ASRS Text

Title: AN MLG CREW, WITH ALL OF THE BELLS AND WHITLES, FORGOT TO CHANGE THEIR ALTIMETERS TO 29 PT 92 ON CLB OUT. THEY FOUND THIS OUT ON DSCNT.

Narrative: ON DSCNT FROM CRUISE ALT OF 31000 FT, BOTH PLTS DISCOVERED ALTIMETERS WERE NEVER SET TO 29.92 DURING CRUISE AT FL310. ALTIMETERS WERE STILL SET AT 30.44, RESULTING IN A 460 FT ERROR WHILE CRUISING AT 31000 FT. THE MLG HAS A BUTTON TO PUSH TO CHANGE THE ALTIMETERS FROM 29.92 TO THE LCL SETTING, INSTEAD OF THE USUAL SETTING KNOB LOCATED ON THE ALTIMETER. FOR SOME REASON, I FIND IT HARDER TO REMEMBER TO CHANGE THE ALTIMETER SETTINGS WHILE PASSING 18000 FT THAN IN OTHER ACFT. ALL OTHER MLG PLTS I'VE TALKED TO ALSO RPT HAVING THE SAME DIFFICULTY. THE CTLR HANDLING OUR FLT NEVER MENTIONED AN ALT DISCREPANCY, SO I ASSUME HE NEVER NOTICED IT. IT SURE WOULD ENHANCE SAFETY IF A WARNING CHIME COULD BE INSTALLED TO GO OFF WHILE PASSING 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.