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The flight crew did not notice FMC altitude alert had reverted to 10000' due to a power interruption. On departure flight crew failed to adhere to clearance to maintain 5000'.
| Attributes | |
| ACN | 105660 |
| Time | |
| Date | 198903 |
| Day | Sun |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | airport : ord |
| State Reference | IL |
| Altitude | msl bound lower : 5000 msl bound upper : 6700 |
| Environment | |
| Flight Conditions | VMC |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | tracon : ord tower : dfw |
| Operator | common carrier : air carrier |
| Make Model Name | Medium Large Transport, Low Wing, 2 Turbojet Eng |
| Navigation In Use | Other Other |
| Flight Phase | climbout : intermediate altitude |
| Route In Use | departure sid : sid |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp pilot : commercial pilot : instrument |
| Experience | flight time last 90 days : 200 flight time total : 18000 flight time type : 1500 |
| ASRS Report | 105660 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : flight engineer pilot : atp |
| Experience | flight time last 90 days : 120 flight time total : 6000 flight time type : 500 |
| ASRS Report | 105661 |
| Events | |
| Anomaly | aircraft equipment problem : less severe altitude deviation : overshoot non adherence : clearance |
| Independent Detector | other controllera |
| Resolutory Action | controller : issued new clearance flight crew : became reoriented none taken : detected after the fact |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
Air carrier trip xx ord-msp medium large transport APU gen inoperative requiring #1 engine to be started at gate. Altitude alert and flight instrument set prior to engine start. First officer and captain saw 5000' in the altitude alert window. During start (#1 engine) ground power was interrupted, at which time I believe the altitude alert defaulted to its power up value of 10000'. This was unnoticed by either pilot. First officer was flying. We departed runway 32L. Rate of climb 4000 FPM. At about 3500' I noticed a glitch in the pressurization and attended go standby. The first officer looked at the altitude alert system which indicated 10000' and continued to climb. At approximately 6500' departure asked what our altitude was, and I replied 6700'. He said, 'you were only cleared to 5000', climb and maintain 14000' heading 270.' I can only think that the power interruption changed the alert system. Coupled with my distraction with the pressure problem and the first officer thinking that we were cleared to 10000', we blew it! There was no traffic conflict. I called departure control from msp and discussed the mishap.
Original NASA ASRS Text
Title: THE FLT CREW DID NOT NOTICE FMC ALT ALERT HAD REVERTED TO 10000' DUE TO A POWER INTERRUPTION. ON DEP FLT CREW FAILED TO ADHERE TO CLRNC TO MAINTAIN 5000'.
Narrative: ACR TRIP XX ORD-MSP MLG APU GEN INOP REQUIRING #1 ENG TO BE STARTED AT GATE. ALT ALERT AND FLT INSTRUMENT SET PRIOR TO ENG START. F/O AND CAPT SAW 5000' IN THE ALT ALERT WINDOW. DURING START (#1 ENG) GND PWR WAS INTERRUPTED, AT WHICH TIME I BELIEVE THE ALT ALERT DEFAULTED TO ITS POWER UP VALUE OF 10000'. THIS WAS UNNOTICED BY EITHER PLT. F/O WAS FLYING. WE DEPARTED RWY 32L. RATE OF CLB 4000 FPM. AT ABOUT 3500' I NOTICED A GLITCH IN THE PRESSURIZATION AND ATTENDED GO STANDBY. THE F/O LOOKED AT THE ALT ALERT SYS WHICH INDICATED 10000' AND CONTINUED TO CLB. AT APPROX 6500' DEP ASKED WHAT OUR ALT WAS, AND I REPLIED 6700'. HE SAID, 'YOU WERE ONLY CLRED TO 5000', CLB AND MAINTAIN 14000' HDG 270.' I CAN ONLY THINK THAT THE PWR INTERRUPTION CHANGED THE ALERT SYS. COUPLED WITH MY DISTR WITH THE PRESSURE PROB AND THE F/O THINKING THAT WE WERE CLRED TO 10000', WE BLEW IT! THERE WAS NO TFC CONFLICT. I CALLED DEP CTL FROM MSP AND DISCUSSED THE MISHAP.
Data retrieved from NASA's ASRS site as of August 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.