Narrative:

While cruising at FL360 the yaw damper inoperative light illuminated; all of the captain's instruments panels went black and the VHF #1 radio failed. It appeared that the captain's instrument bus had failed but there were no lights indicating that that is what actually happened. The source selector was placed in the both on right position with no effect.while going through the checklist we missed a frequency change; since we had not yet switched to the VHF #2 radio. Since we had passed our normal descent point with no contact from center we squawked 7600 and then when we decided it was time to start the descent we changed the squawk to 7700 and commenced the descent. Shortly thereafter we receive an ACARS message from dispatch to contact center and were given the proper frequency. We then switched to the #2 VHF radio and reestablished contact with center.at no time were we able to restore the captain's instruments so the first officer continued to fly the approach and get the aircraft on the ground. We did not have a bus off light or any indication of a generator failure so it was a little confusing as to just what our exact problem was. We knew we had lost a bus but did not get the indications we expected to get to identify exactly which.upon landing the left thrust reverser would not deploy and the first officer elected to use no reversers at all. At the gate maintenance found a standby bus circuit breaker popped and speculated that it could have been caused by the first officer's bag; which he hangs from the bar by the back window. Since the first officer was flying the aircraft at the time of the incident and in smooth weather conditions we do not think his bag had any effect of the circuit breaker popping; but do not know for sure.

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Original NASA ASRS Text

Title: A B737-800 flight crew encountered numerous system failures when the Circuit Breaker for the Captain's standby buss opened. Maintenance speculated the First Officer's bag; which was hung in a place and manner which placed it in proximity to the breaker; may have struck and opened the breaker.

Narrative: While cruising at FL360 the yaw damper inoperative light illuminated; all of the Captain's instruments panels went black and the VHF #1 radio failed. It appeared that the Captain's instrument bus had failed but there were no lights indicating that that is what actually happened. The source selector was placed in the both on right position with no effect.While going through the checklist we missed a frequency change; since we had not yet switched to the VHF #2 radio. Since we had passed our normal descent point with no contact from Center we squawked 7600 and then when we decided it was time to start the descent we changed the squawk to 7700 and commenced the descent. Shortly thereafter we receive an ACARS message from Dispatch to contact Center and were given the proper frequency. We then switched to the #2 VHF radio and reestablished contact with Center.At no time were we able to restore the Captain's instruments so the First Officer continued to fly the approach and get the aircraft on the ground. We did not have a bus off light or any indication of a generator failure so it was a little confusing as to just what our exact problem was. We knew we had lost a bus but did not get the indications we expected to get to identify exactly which.Upon landing the left thrust reverser would not deploy and the First Officer elected to use no reversers at all. At the gate maintenance found a standby bus circuit breaker popped and speculated that it could have been caused by the First Officer's bag; which he hangs from the bar by the back window. Since the First Officer was flying the aircraft at the time of the incident and in smooth weather conditions we do not think his bag had any effect of the circuit breaker popping; but do not know for sure.

Data retrieved from NASA's ASRS site as of April 2012 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.