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Altitude deviation altitude excursion. The altitude hold had been malfunctioning, but this air carrier continued to use it anyway and climbed 400 ft above the assigned altitude.
| Attributes | |
| ACN | 307782 |
| Time | |
| Date | 199506 |
| Day | Thu |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | atc facility : zzz |
| State Reference | US |
| Altitude | msl bound lower : 37000 msl bound upper : 37400 |
| Aircraft 1 | |
| Controlling Facilities | artcc : zzz |
| Operator | common carrier : air carrier |
| Make Model Name | MD-80 Super 80 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other |
| Flight Phase | cruise other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| ASRS Report | 307782 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : commercial pilot : instrument |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other |
| Independent Detector | aircraft equipment other aircraft equipment : unspecified other controllera other flight crewa |
| Resolutory Action | flight crew : returned to intended course or assigned course flight crew : overcame equipment problem other |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
At FL370, .78 mach, the autoplt was constantly making small, gentle pitch changes corresponding to about 300 FPM, although altitude never deviated more than 100 ft. But in a turn over a waypoint at 20 degrees of bank, the pitch oscillations became 1000 FPM, causing the aircraft to climb to FL374 before the autoplt could be disengaged. ATC was notified of the problem, and that we were correcting to FL370. ATC acknowledged the call, without any further comment. The remainder of the flight was normal, and an E-6 entry was accomplished at the destination.
Original NASA ASRS Text
Title: ALTDEV ALT EXCURSION. THE ALT HOLD HAD BEEN MALFUNCTIONING, BUT THIS ACR CONTINUED TO USE IT ANYWAY AND CLBED 400 FT ABOVE THE ASSIGNED ALT.
Narrative: AT FL370, .78 MACH, THE AUTOPLT WAS CONSTANTLY MAKING SMALL, GENTLE PITCH CHANGES CORRESPONDING TO ABOUT 300 FPM, ALTHOUGH ALT NEVER DEVIATED MORE THAN 100 FT. BUT IN A TURN OVER A WAYPOINT AT 20 DEGS OF BANK, THE PITCH OSCILLATIONS BECAME 1000 FPM, CAUSING THE ACFT TO CLB TO FL374 BEFORE THE AUTOPLT COULD BE DISENGAGED. ATC WAS NOTIFIED OF THE PROB, AND THAT WE WERE CORRECTING TO FL370. ATC ACKNOWLEDGED THE CALL, WITHOUT ANY FURTHER COMMENT. THE REMAINDER OF THE FLT WAS NORMAL, AND AN E-6 ENTRY WAS ACCOMPLISHED AT THE DEST.
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.