Air carrier medium large transport flight crew encounters strange electrical problems.

Attributes
ACN	179717
Time
Date	199105
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : mci
State Reference	MO
Altitude	msl bound lower : 37000 msl bound upper : 37000
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	cruise other descent other other
Route In Use	enroute airway : zkc
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 175 flight time total : 13000 flight time type : 1400
ASRS Report	179717
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 180 flight time total : 7500 flight time type : 600
ASRS Report	179919
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	aircraft : equipment problem dissipated other
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

Air carrier flight from lax to day, first flight of the day. The crew bringing the aircraft into lax the night before had written up a problem encountered after landing--maintenance changed 2 gen control units and a bus protection panel. We'd been airborne about 1 hour, 50 mins when the captain's instruments went off and on 3 times over a short period. The F/a's reported loss of galley power and some cabin lights during these periods. We also showed loss of some window heat. While these symptoms were in evidence, no electrical malfunctions were indicated, but the #1 gen showed 124 volts. During this period we asked for descent from our cruisng altitude of FL370 in order to start the APU. After multiple unsuccessful start attempts, we realized that we had exceeded the APU starter limitations. Also during this period the #1 TR circuit breaker popped. We felt that this must have been the source of the problem since the problem did not recur after the circuit breaker popped. Since the APU wouldn't start, we climbed back to FL370 and planned to continue to dayton. We advised our dispatcher of our situation and our intentions. He concurred with our plan. Approaching kansas city, we were noting heavy WX from east of mci to day. Abeam mci, the original problem did recur, about 1:20 after the first 3 times. We immediately asked ATC for diversion into mci. The abnormal symptoms repeated about 5 times during descent and approach. In addition, the left IRS annunciated 'on dc' twice and the FMC failed for about 30 seconds before coming back on. After landing, the stick shakers activated nd then both air conditioning packs tripped off. The mechanics in kansas city found 1 pin on the #1 gen leads cannon plug from the engine area to the pylon to be burned. The cannon plug and CSD were disconnected, APU normal operation was verified, left buss off sensing normal operation was verified, and we ferried the aircraft to charlotte.

Original NASA ASRS Text

Title: ACR MLG FLT CREW ENCOUNTERS STRANGE ELECTRICAL PROBLEMS.

Narrative: ACR FLT FROM LAX TO DAY, FIRST FLT OF THE DAY. THE CREW BRINGING THE ACFT INTO LAX THE NIGHT BEFORE HAD WRITTEN UP A PROB ENCOUNTERED AFTER LNDG--MAINT CHANGED 2 GEN CTL UNITS AND A BUS PROTECTION PANEL. WE'D BEEN AIRBORNE ABOUT 1 HR, 50 MINS WHEN THE CAPT'S INSTRUMENTS WENT OFF AND ON 3 TIMES OVER A SHORT PERIOD. THE F/A'S RPTED LOSS OF GALLEY PWR AND SOME CABIN LIGHTS DURING THESE PERIODS. WE ALSO SHOWED LOSS OF SOME WINDOW HEAT. WHILE THESE SYMPTOMS WERE IN EVIDENCE, NO ELECTRICAL MALFUNCTIONS WERE INDICATED, BUT THE #1 GEN SHOWED 124 VOLTS. DURING THIS PERIOD WE ASKED FOR DSNT FROM OUR CRUISNG ALT OF FL370 IN ORDER TO START THE APU. AFTER MULTIPLE UNSUCCESSFUL START ATTEMPTS, WE REALIZED THAT WE HAD EXCEEDED THE APU STARTER LIMITATIONS. ALSO DURING THIS PERIOD THE #1 TR CB POPPED. WE FELT THAT THIS MUST HAVE BEEN THE SOURCE OF THE PROB SINCE THE PROB DID NOT RECUR AFTER THE CB POPPED. SINCE THE APU WOULDN'T START, WE CLBED BACK TO FL370 AND PLANNED TO CONTINUE TO DAYTON. WE ADVISED OUR DISPATCHER OF OUR SITUATION AND OUR INTENTIONS. HE CONCURRED WITH OUR PLAN. APCHING KANSAS CITY, WE WERE NOTING HEAVY WX FROM E OF MCI TO DAY. ABEAM MCI, THE ORIGINAL PROB DID RECUR, ABOUT 1:20 AFTER THE FIRST 3 TIMES. WE IMMEDIATELY ASKED ATC FOR DIVERSION INTO MCI. THE ABNORMAL SYMPTOMS REPEATED ABOUT 5 TIMES DURING DSNT AND APCH. IN ADDITION, THE LEFT IRS ANNUNCIATED 'ON DC' TWICE AND THE FMC FAILED FOR ABOUT 30 SECS BEFORE COMING BACK ON. AFTER LNDG, THE STICK SHAKERS ACTIVATED ND THEN BOTH AIR CONDITIONING PACKS TRIPPED OFF. THE MECHS IN KANSAS CITY FOUND 1 PIN ON THE #1 GEN LEADS CANNON PLUG FROM THE ENG AREA TO THE PYLON TO BE BURNED. THE CANNON PLUG AND CSD WERE DISCONNECTED, APU NORMAL OPERATION WAS VERIFIED, LEFT BUSS OFF SENSING NORMAL OPERATION WAS VERIFIED, AND WE FERRIED THE ACFT TO CHARLOTTE.

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.