A B737-300 in cruise at FL330 declared an emergency and diverted due to the #1 xfer bus electrical f...

Attributes
ACN	400615
Time
Date	199804
Day	Mon
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : ind
State Reference	IN
Altitude	msl bound lower : 33000 msl bound upper : 33000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zid
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	cruise other other other
Route In Use	enroute airway : zid
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : flight engineer pilot : commercial pilot : atp
Experience	flight time last 90 days : 250 flight time total : 16850 flight time type : 9000
ASRS Report	400615
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	flight crew : declared emergency other
Consequence	Other
Supplementary
Primary Problem	Aircraft

Narrative:

Cruising at FL330 en route from phx to ewr, #1 xfer bus circuit breaker popped. We waited several mins and reset the circuit breaker. After a few mins the circuit breaker popped again along with the #1 engine aft fuel boost pump. We had numerous instrument and system flags. While we were trying to assess the situation, the altitude warning horn went off. We were able to control the cabin, requested descent from ATC, and landed uneventfully in ind. Callback conversation with reporter revealed the following information: the reporter stated the aircraft was a B737-300 and the cause of the xfer bus failure was not reported by maintenance to the crew. The reporter said that when the xfer bus failed the standby AC and dc busses were powered by the battery and worked normally.

Original NASA ASRS Text

Title: A B737-300 IN CRUISE AT FL330 DECLARED AN EMER AND DIVERTED DUE TO THE #1 XFER BUS ELECTRICAL FAILURE.

Narrative: CRUISING AT FL330 ENRTE FROM PHX TO EWR, #1 XFER BUS CIRCUIT BREAKER POPPED. WE WAITED SEVERAL MINS AND RESET THE CIRCUIT BREAKER. AFTER A FEW MINS THE CIRCUIT BREAKER POPPED AGAIN ALONG WITH THE #1 ENG AFT FUEL BOOST PUMP. WE HAD NUMEROUS INST AND SYS FLAGS. WHILE WE WERE TRYING TO ASSESS THE SIT, THE ALT WARNING HORN WENT OFF. WE WERE ABLE TO CTL THE CABIN, REQUESTED DSCNT FROM ATC, AND LANDED UNEVENTFULLY IN IND. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE ACFT WAS A B737-300 AND THE CAUSE OF THE XFER BUS FAILURE WAS NOT RPTED BY MAINT TO THE CREW. THE RPTR SAID THAT WHEN THE XFER BUS FAILED THE STANDBY AC AND DC BUSSES WERE POWERED BY THE BATTERY AND WORKED NORMALLY.

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.

A B737-300 in cruise at FL330 declared an emergency and diverted due to the #1 xfer bus electrical failure.