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An air carrier B757 flight crew has an electrical malfunction as they were leveling from a descent and they overshot their altitude by 175 ft before manually recovering.
| Attributes | |
| ACN | 377190 |
| Time | |
| Date | 199708 |
| Day | Sun |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | atc facility : jli |
| State Reference | CA |
| Altitude | msl bound lower : 30825 msl bound upper : 31000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zla |
| Operator | common carrier : air carrier |
| Make Model Name | B757 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other Other |
| Flight Phase | descent other |
| Route In Use | arrival other arrival star : star enroute airway : zla |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : cfi pilot : flight engineer pilot : atp |
| Experience | flight time last 90 days : 120 flight time total : 16000 flight time type : 450 |
| ASRS Report | 377190 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | aircraft equipment problem : less severe altitude deviation : overshoot non adherence : clearance other anomaly other |
| Independent Detector | aircraft equipment other aircraft equipment : unspecified other flight crewa |
| Resolutory Action | flight crew : returned to intended course or assigned course flight crew : overcame equipment problem |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Aircraft |
| Air Traffic Incident | Pilot Deviation other |
Narrative:
Flight cleared from FL350 to FL310 just prior to jli VOR. Just prior to leveling off at FL310, both xponders failed and (both transponder data buses) 'intermittently.' and, leveling off from a 3500 FPM descent at FL310 (captain flying) the autoplt and autothrottles disconnected causing an altitude bust of approximately 175 ft prior to reverting to manual control. We advised center of these electronic failures and they were helpful. When flight was handed off to the next sector, the controller asked 'souls' and 'fuel' as if we had an emergency. We advised no emergency, but no xponders and autoplt unreliability. Flight landed uneventfully.
Original NASA ASRS Text
Title: AN ACR B757 FLC HAS AN ELECTRICAL MALFUNCTION AS THEY WERE LEVELING FROM A DSCNT AND THEY OVERSHOT THEIR ALT BY 175 FT BEFORE MANUALLY RECOVERING.
Narrative: FLT CLRED FROM FL350 TO FL310 JUST PRIOR TO JLI VOR. JUST PRIOR TO LEVELING OFF AT FL310, BOTH XPONDERS FAILED AND (BOTH XPONDER DATA BUSES) 'INTERMITTENTLY.' AND, LEVELING OFF FROM A 3500 FPM DSCNT AT FL310 (CAPT FLYING) THE AUTOPLT AND AUTOTHROTTLES DISCONNECTED CAUSING AN ALT BUST OF APPROX 175 FT PRIOR TO REVERTING TO MANUAL CTL. WE ADVISED CTR OF THESE ELECTRONIC FAILURES AND THEY WERE HELPFUL. WHEN FLT WAS HANDED OFF TO THE NEXT SECTOR, THE CTLR ASKED 'SOULS' AND 'FUEL' AS IF WE HAD AN EMER. WE ADVISED NO EMER, BUT NO XPONDERS AND AUTOPLT UNRELIABILITY. FLT LANDED UNEVENTFULLY.
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.