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B767-300 captain reported returning to departure airport after noting multiple electrical anomalies that were addressed before departure but not successfully solved.
| Attributes | |
| ACN | 1249961 |
| Time | |
| Date | 201503 |
| Local Time Of Day | 0001-0600 |
| Place | |
| Locale Reference | ZZZ.ARTCC |
| State Reference | US |
| Environment | |
| Flight Conditions | VMC |
| Aircraft 1 | |
| Make Model Name | B767-300 and 300 ER |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Cruise |
| Component | |
| Aircraft Component | Electrical Power |
| Person 1 | |
| Function | Pilot Flying |
| Experience | Flight Crew Total 18500 |
| Events | |
| Anomaly | Aircraft Equipment Problem Less Severe |
Narrative:
This was the 3rd air interrupt in a row on this aircraft for the same problem. Prior to this flight maintenance personnel had been brought in to help contract maintenance. There were at least 3 shipments of parts in an attempt to fix problem. Prior to flight; mx replaced a loose wire connector; a T/right unit for ca instruments; left idg; an overhead electronics panel and possibly more- see logbook. Here's what happened again. About 25 min into flight at FL390; lighter aircraft because ferry without rev passengers; little chop in area; - everything associated with the standby AC bus started cycling rapidly and violently to include: left autopilot engaged was erratic (changed autopilots); cabin alt indicators bouncing rapidly back and forth; yaw damper light; flood lights cycling on off; radar cycling on off; left FMC blanking; cabin lights cycling; status msg 'capt instr xfer'; and may have been other indications. We turned around [to departure airport; before] entering oceanic. On descent; systems returned to normal (at lower altitudes and throttles back); and so descent - approach and landing were normal; not overweight this time. Arff checked brakes; no problem; and returned to gate uneventful.because this problem has only occurred during flight; I recommend test pilots fly this aircraft to altitude for systems check prior to revenue flight; following further maintenance.
Original NASA ASRS Text
Title: B767-300 Captain reported returning to departure airport after noting multiple electrical anomalies that were addressed before departure but not successfully solved.
Narrative: This was the 3rd Air Interrupt in a row on this aircraft for the same problem. Prior to this flight maintenance personnel had been brought in to help contract maintenance. There were at least 3 shipments of parts in an attempt to fix problem. Prior to flight; MX replaced a loose wire connector; a T/R unit for CA instruments; left idg; an overhead electronics panel and possibly more- see logbook. Here's what happened again. About 25 min into flight at FL390; lighter aircraft because ferry without rev passengers; little chop in area; - everything associated with the Standby AC bus started cycling rapidly and violently to include: L autopilot engaged was erratic (changed autopilots); Cabin Alt Indicators bouncing rapidly back and forth; yaw damper light; flood lights cycling on off; radar cycling on off; L FMC blanking; cabin lights cycling; Status Msg 'Capt Instr Xfer'; and may have been other indications. We turned around [to departure airport; before] entering oceanic. On descent; systems returned to normal (at lower altitudes and throttles back); and so descent - approach and landing were normal; not overweight this time. ARFF checked brakes; no problem; and returned to gate uneventful.Because this problem has only occurred during flight; I recommend test pilots fly this aircraft to altitude for systems check prior to revenue flight; following further maintenance.
Data retrieved from NASA's ASRS site 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.