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An air carrier medium large transport, with 3 pilots aboard, descended through their assigned altitude because they all heard the wrong altimeter setting.
| Attributes | |
| ACN | 234308 |
| Time | |
| Date | 199302 |
| Day | Sun |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | airport : ord |
| State Reference | IL |
| Altitude | msl bound lower : 15440 msl bound upper : 19000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Operator | common carrier : air carrier |
| Make Model Name | Medium Large Transport, Low Wing, 2 Turbojet Eng |
| Navigation In Use | Other Other |
| Flight Phase | descent other |
| Route In Use | enroute airway : zau |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | observation : company check pilot oversight : pic |
| Qualification | pilot : atp pilot : cfi pilot : flight engineer |
| Experience | flight time last 90 days : 200 flight time total : 15000 flight time type : 4000 |
| ASRS Report | 234308 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : single pilot |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 150 flight time total : 13000 flight time type : 750 |
| ASRS Report | 234402 |
| Events | |
| Anomaly | altitude deviation : overshoot non adherence : clearance other anomaly other |
| Independent Detector | other controllera |
| Resolutory Action | controller : issued new clearance other |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Ambiguous |
| Air Traffic Incident | other |
Narrative:
Cleared to descend to 16000 ft by ZAU. Altimeter setting was 29.36 in hg. During first officer 10E, we had neglected to reset altimeter while descending through FL180. Aircraft leveled at approximately 15440 MSL because altimeter was set to 29.92 instead of 29.36. First officer called it to my attention and I corrected the problem immediately. The FMS was controling the medium large transport. It had leveled at what it thought was 16000 ft. When I reset the altimeter, it stayed stuck in 'altitude hold.' I had to kick off the autoplt to get it to change altitude. FMS's should be set up to accept altimeter changes at any time, even after altitude capture.
Original NASA ASRS Text
Title: AN ACR MLG, WITH 3 PLTS ABOARD, DSNDED THROUGH THEIR ASSIGNED ALT BECAUSE THEY ALL HEARD THE WRONG ALTIMETER SETTING.
Narrative: CLRED TO DSND TO 16000 FT BY ZAU. ALTIMETER SETTING WAS 29.36 IN HG. DURING FO 10E, WE HAD NEGLECTED TO RESET ALTIMETER WHILE DSNDING THROUGH FL180. ACFT LEVELED AT APPROX 15440 MSL BECAUSE ALTIMETER WAS SET TO 29.92 INSTEAD OF 29.36. FO CALLED IT TO MY ATTN AND I CORRECTED THE PROB IMMEDIATELY. THE FMS WAS CTLING THE MLG. IT HAD LEVELED AT WHAT IT THOUGHT WAS 16000 FT. WHEN I RESET THE ALTIMETER, IT STAYED STUCK IN 'ALT HOLD.' I HAD TO KICK OFF THE AUTOPLT TO GET IT TO CHANGE ALT. FMS'S SHOULD BE SET UP TO ACCEPT ALTIMETER CHANGES AT ANY TIME, EVEN AFTER ALT CAPTURE.
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.