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37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
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B737 flight crew altitude overshoot due to first officer's altimeter set 1 inch higher than captain's altimeter. 1000 ft difference not noted until passing 10000 ft.
| Attributes | |
| ACN | 678662 |
| Time | |
| Date | 200511 |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | intersection : benky |
| State Reference | IL |
| Altitude | msl single value : 11000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Operator | common carrier : air carrier |
| Make Model Name | B737 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | descent : approach |
| Route In Use | arrival star : n/a |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : instrument pilot : multi engine pilot : atp pilot : cfi pilot : commercial pilot : flight engineer |
| Experience | flight time last 90 days : 240 flight time total : 15000 flight time type : 5000 |
| ASRS Report | 678662 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : commercial pilot : cfi pilot : atp pilot : multi engine pilot : instrument pilot : flight engineer |
| Experience | flight time last 90 days : 240 flight time total : 10000 flight time type : 2800 |
| ASRS Report | 678664 |
| Events | |
| Anomaly | altitude deviation : overshoot inflight encounter : turbulence non adherence : clearance non adherence : far non adherence : published procedure |
| Independent Detector | other flight crewa |
| Resolutory Action | flight crew : returned to assigned altitude |
| Supplementary | |
| Problem Areas | Weather Flight Crew Human Performance |
| Primary Problem | Flight Crew Human Performance |
Narrative:
On descent into ord; given altimeter setting of 29.34. Because it was so low; doublechked with ord ATIS and found it was correct. Going through FL180; called and set 29.34 on both altimeters on my side and crosschecked first officer side; but apparently only the last 2 digits. Did not realize at that point that it was set at 30.34. Since that produced a difference of almost 1000 ft; I did not recognize the discrepancy as dials were winding down in tandem. As 10 stared showing on my altimeter digital readout; I realized something was amiss. First officer immediately stopped descent; reset and leveled at 11000 ft. Believe we missed our altitude by 300-500 ft. Contributing factor was fatigue. Also had turbulence a little earlier on and had seatbelt sign off deeper into descent than normal and was making return to seat announcement when 1000 ft to go call should have been made. Very experienced flight crew that made an error that 99 out of 100 times would have been caught. Gave me a wake-up call.
Original NASA ASRS Text
Title: B737 FLT CREW ALT OVERSHOOT DUE TO FO'S ALTIMETER SET 1 INCH HIGHER THAN CAPT'S ALTIMETER. 1000 FT DIFFERENCE NOT NOTED UNTIL PASSING 10000 FT.
Narrative: ON DSCNT INTO ORD; GIVEN ALTIMETER SETTING OF 29.34. BECAUSE IT WAS SO LOW; DOUBLECHKED WITH ORD ATIS AND FOUND IT WAS CORRECT. GOING THROUGH FL180; CALLED AND SET 29.34 ON BOTH ALTIMETERS ON MY SIDE AND XCHKED FO SIDE; BUT APPARENTLY ONLY THE LAST 2 DIGITS. DID NOT REALIZE AT THAT POINT THAT IT WAS SET AT 30.34. SINCE THAT PRODUCED A DIFFERENCE OF ALMOST 1000 FT; I DID NOT RECOGNIZE THE DISCREPANCY AS DIALS WERE WINDING DOWN IN TANDEM. AS 10 STARED SHOWING ON MY ALTIMETER DIGITAL READOUT; I REALIZED SOMETHING WAS AMISS. FO IMMEDIATELY STOPPED DSCNT; RESET AND LEVELED AT 11000 FT. BELIEVE WE MISSED OUR ALT BY 300-500 FT. CONTRIBUTING FACTOR WAS FATIGUE. ALSO HAD TURB A LITTLE EARLIER ON AND HAD SEATBELT SIGN OFF DEEPER INTO DSCNT THAN NORMAL AND WAS MAKING RETURN TO SEAT ANNOUNCEMENT WHEN 1000 FT TO GO CALL SHOULD HAVE BEEN MADE. VERY EXPERIENCED FLT CREW THAT MADE AN ERROR THAT 99 OUT OF 100 TIMES WOULD HAVE BEEN CAUGHT. GAVE ME A WAKE-UP CALL.
Data retrieved from NASA's ASRS site as of January 2009 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.