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B727 flight crew experiences a possible altitude deviation caused by an altitude alerter/autopilot malfunction. Fatigue was a contributing factor in the incident.
| Attributes | |
| ACN | 951858 |
| Time | |
| Date | 201106 |
| Local Time Of Day | 1801-2400 |
| Place | |
| Locale Reference | ZZZ.Airport |
| State Reference | US |
| Environment | |
| Flight Conditions | VMC |
| Light | Night |
| Aircraft 1 | |
| Make Model Name | B727 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Climb |
| Route In Use | Direct |
| Flight Plan | IFR |
| Component | |
| Aircraft Component | Altitude Hold/Capture |
| Person 1 | |
| Function | Captain Pilot Not Flying |
| Qualification | Flight Crew Air Transport Pilot (ATP) |
| Experience | Flight Crew Last 90 Days 31 Flight Crew Total 14000 Flight Crew Type 2000 |
| Person 2 | |
| Function | Pilot Flying First Officer |
| Qualification | Flight Crew Air Transport Pilot (ATP) |
| Experience | Flight Crew Last 90 Days 42 Flight Crew Total 3300 Flight Crew Type 1275 |
| Events | |
| Anomaly | Aircraft Equipment Problem Less Severe Deviation - Altitude Overshoot Deviation - Procedural Clearance |
Narrative:
The CADC (for some reason) was in dads 2 which made the altitude alerter inoperative. We asked center if we could stop the climb at FL180 to troubleshoot the problem. I was concerned that we had missed or not made the correct level off and when center was queried they indicated that there were no issues and for us to maintain FL180 until we were sure what our problem was. After reselecting dads 1 and continuing the climb; the alerter performed normally for the remainder of the flight. A causal factor was crew fatigue. This was a difficult trip with 2 'circadian flips' and 2 trip revisions in as many days and we were not well rested. The altitude alerter fail flag is difficult to see at night and there are no aural or visual warnings (other than the light cap for the CADC select) that the altitude alerter had failed.
Original NASA ASRS Text
Title: B727 flight crew experiences a possible altitude deviation caused by an altitude alerter/autopilot malfunction. Fatigue was a contributing factor in the incident.
Narrative: The CADC (for some reason) was in DADS 2 which made the altitude alerter inoperative. We asked Center if we could stop the climb at FL180 to troubleshoot the problem. I was concerned that we had missed or not made the correct level off and when Center was queried they indicated that there were no issues and for us to maintain FL180 until we were sure what our problem was. After reselecting DADS 1 and continuing the climb; the alerter performed normally for the remainder of the flight. A causal factor was crew fatigue. This was a difficult trip with 2 'circadian flips' and 2 trip revisions in as many days and we were not well rested. The altitude alerter fail flag is difficult to see at night and there are no aural or visual warnings (other than the light cap for the CADC select) that the altitude alerter had failed.
Data retrieved from NASA's ASRS site as of April 2012 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.