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A B737-700 in climb at FL310 diverted due to left buss electrical failures with no xfer buss switching caused by left generator failure.
| Attributes | |
| ACN | 545395 |
| Time | |
| Date | 200201 |
| Day | Mon |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | navaid : pwl.vor |
| State Reference | NY |
| Altitude | msl single value : 31000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zbw.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | B737-700 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | other |
| Flight Phase | cruise : enroute altitude change |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 100 flight time total : 5300 flight time type : 100 |
| ASRS Report | 545395 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time total : 11000 flight time type : 5000 |
| ASRS Report | 545394 |
| Events | |
| Anomaly | aircraft equipment problem : critical other anomaly other |
| Independent Detector | aircraft equipment other aircraft equipment : left bus warning lights other flight crewa other flight crewb |
| Resolutory Action | aircraft : equipment problem dissipated flight crew : diverted to another airport flight crew : landed as precaution |
| Consequence | other |
| Supplementary | |
| Problem Areas | Maintenance Human Performance Flight Crew Human Performance Aircraft |
| Primary Problem | Aircraft |
Narrative:
During our climb while passing FL310, the autoplt and yaw damper disconnected, the captain's du's began to flash, and the #1 xfer buss off light illuminated. The captain also noticed that the cabin altitude was beginning to climb. We asked ATC for an immediate descent and for a diversion to ZZZ. During the descent, the APU was started and put on the buss. At this time, the system returned to normal. We continued to ZZZ where maintenance was able to take a look at the problem. Supplemental information from acn 545394: passing through FL310, received various lights and autoplt disconnect. Captain's flight instrument screens were flashing and cabin altitude was climbing. #1 generator was MEL'ed after maintenance in ZZZ conferred with company maintenance and also did several engine runs and we continued to ZZZ1 after 1 hour. Callback conversation with reporter acn 545395 revealed the following information: the reporter stated it was confirmed by maintenance the generator had failed but the failure to power the xfer buss and any corrective action taken is unknown.
Original NASA ASRS Text
Title: A B737-700 IN CLB AT FL310 DIVERTED DUE TO L BUSS ELECTRICAL FAILURES WITH NO XFER BUSS SWITCHING CAUSED BY L GENERATOR FAILURE.
Narrative: DURING OUR CLB WHILE PASSING FL310, THE AUTOPLT AND YAW DAMPER DISCONNECTED, THE CAPT'S DU'S BEGAN TO FLASH, AND THE #1 XFER BUSS OFF LIGHT ILLUMINATED. THE CAPT ALSO NOTICED THAT THE CABIN ALT WAS BEGINNING TO CLB. WE ASKED ATC FOR AN IMMEDIATE DSCNT AND FOR A DIVERSION TO ZZZ. DURING THE DSCNT, THE APU WAS STARTED AND PUT ON THE BUSS. AT THIS TIME, THE SYS RETURNED TO NORMAL. WE CONTINUED TO ZZZ WHERE MAINT WAS ABLE TO TAKE A LOOK AT THE PROB. SUPPLEMENTAL INFO FROM ACN 545394: PASSING THROUGH FL310, RECEIVED VARIOUS LIGHTS AND AUTOPLT DISCONNECT. CAPT'S FLT INST SCREENS WERE FLASHING AND CABIN ALT WAS CLBING. #1 GENERATOR WAS MEL'ED AFTER MAINT IN ZZZ CONFERRED WITH COMPANY MAINT AND ALSO DID SEVERAL ENG RUNS AND WE CONTINUED TO ZZZ1 AFTER 1 HR. CALLBACK CONVERSATION WITH RPTR ACN 545395 REVEALED THE FOLLOWING INFO: THE RPTR STATED IT WAS CONFIRMED BY MAINT THE GENERATOR HAD FAILED BUT THE FAILURE TO PWR THE XFER BUSS AND ANY CORRECTIVE ACTION TAKEN IS UNKNOWN.
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.