Narrative:

En route form phx - bwi the master caution light came on. The equipment cooling off light was on. The captain selected the alternate switch position and their light went out. I referred to the checklist in the pilot operating handbook. About this time, the lead F/a advised the captain of loss of aft galley power and sidewall lights on both sides of the aircraft. The captain referred to the communication section of vol 1 for the commercial radio frequency for our location. A phone patch was then set up with maintenance in pit to discuss the situation. Maintenance advised us that they would notify bwi. Descending into the bwi terminal area, the master caution light came on again. Both IRS dc fail lights were illuminated. We referred to the checklist. A short time later, the speed trim fail light illuminated, followed by both CSD low oil pressure lights. We again referred to the checklist. First officer disconnected the autoplt and the autoplt was returned to the cws mode and the intermittent tone stopped. Bwi approach vectored us to a left base for the ILS 10 final approach course. The captain commented that we may also have additional problems. First officer suggested lowering the landing gear early to make sure it would come down. The gear was extended, and the 3 red gear unsafe lights remained illuminated - with no green light on. At this point we were inbound on the ILS 10 localizer and the captain was flying the aircraft. First officer got the checklist out. We then advised bwi approach and company operations of our situation, and requested to hold to check out our gear indication. We advised the lead F/a of our situation and told him to prepare the cabin. Captain then attempted to inform passengers of our situation, but the PA was inoperative. While being radar vectored in the holding pattern, the captain's ADI and the standby attitude indicator became unreliable. The captain switched to 'both on 2' on the attitude selector switch on the forward overhead panel. We advised approach control to have the emergency equipment standing by. Also, we noticed that the north, and egt indications were inoperative. We attempted to recycle the gear, but were unable to raise the gear handle up past the off position. Using the checklist, the first officer visually inspected the nose gear; the red indicator arrows showed that it was down and locked. The first officer then went back into the cain to visually check the main landing gear. The wheels appeared to be down, but the first officer was unable to verify that they were down and locked with the visibility indicators - the wheel well lights were inoperative. After visibility inspection of the landing gear, the flaps were moved to the 15 degree position to see if the gear unsafe warning horn would sound - it did not, so we agreed that in all probability the landing gear was down and locked. About this time we noticed that the antiskid inoperative light was on. We advised approach control that we wanted to make a flyby and have the gear visually checked. After the flyby, the tower reported that an aircraft at the approach end of runway 10 reported the nlg and rmlg appeared down, but was unsure about the lmlg. An airport vehicle reported that all landing gear appeared to be down. We were advised by the lead F/a that the cabin was prepared and passengers had been briefed by using the hand held megaphone. We informed the tower and company operations of our intention to land. On landing rollout, no reverser unlocked lights were illuminated and the captain was unable to reverse the engines. The aircraft was stopped using brakes and speed brakes. After turning off the runway, we advised the tower that no further assistance was required. We also informed the company that we wanted to have the landing gear pinned and be towed in to the gate. About this time, we heard the lav smoke detector sound and the lead F/a advised us that there was smoke in the cabin. Smoke smell seemed to be increasing, so the captain elected to emergency evacuate/evacuation the aircraft and advised the lead F/a to do so. We accomplished the checklist and advised ground control and the crash fire rescue crew of our intentions. We evacuated the aircraft via the forward escape slides. Callback with reporter revealed the following information. The cause of the ground service bus failure is unknown however the failure apparently resulted in a circuit breaker fire that somehow led to failure of the battery charger as well as several relays in the dc electrical system which manifested itself near the approach phase of the flight. Feedback has not as of yet been provided by the air carrier so reporter is unsure of the exact problems or remedies. The smoke in the aircraft resulting in the aircraft evacuate/evacuation was caused by overheated AC packs and was not of electrical origin.

Related reports:

Google
 

Original NASA ASRS Text

Title: ELECTRICAL SYSTEM DISTRIBUTION BUS FAILURE.

Narrative: ENRTE FORM PHX - BWI THE MASTER CAUTION LIGHT CAME ON. THE EQUIPMENT COOLING OFF LIGHT WAS ON. THE CAPT SELECTED THE ALTERNATE SWITCH POS AND THEIR LIGHT WENT OUT. I REFERRED TO THE CHKLIST IN THE PLT OPERATING HANDBOOK. ABOUT THIS TIME, THE LEAD F/A ADVISED THE CAPT OF LOSS OF AFT GALLEY PWR AND SIDEWALL LIGHTS ON BOTH SIDES OF THE ACFT. THE CAPT REFERRED TO THE COM SECTION OF VOL 1 FOR THE COMMERCIAL RADIO FREQ FOR OUR LOCATION. A PHONE PATCH WAS THEN SET UP WITH MAINT IN PIT TO DISCUSS THE SITUATION. MAINT ADVISED US THAT THEY WOULD NOTIFY BWI. DSNDING INTO THE BWI TERMINAL AREA, THE MASTER CAUTION LIGHT CAME ON AGAIN. BOTH IRS DC FAIL LIGHTS WERE ILLUMINATED. WE REFERRED TO THE CHKLIST. A SHORT TIME LATER, THE SPD TRIM FAIL LIGHT ILLUMINATED, FOLLOWED BY BOTH CSD LOW OIL PRESSURE LIGHTS. WE AGAIN REFERRED TO THE CHKLIST. F/O DISCONNECTED THE AUTOPLT AND THE AUTOPLT WAS RETURNED TO THE CWS MODE AND THE INTERMITTENT TONE STOPPED. BWI APCH VECTORED US TO A L BASE FOR THE ILS 10 FINAL APCH COURSE. THE CAPT COMMENTED THAT WE MAY ALSO HAVE ADDITIONAL PROBS. F/O SUGGESTED LOWERING THE LNDG GEAR EARLY TO MAKE SURE IT WOULD COME DOWN. THE GEAR WAS EXTENDED, AND THE 3 RED GEAR UNSAFE LIGHTS REMAINED ILLUMINATED - WITH NO GREEN LIGHT ON. AT THIS POINT WE WERE INBND ON THE ILS 10 LOC AND THE CAPT WAS FLYING THE ACFT. F/O GOT THE CHKLIST OUT. WE THEN ADVISED BWI APCH AND COMPANY OPS OF OUR SITUATION, AND REQUESTED TO HOLD TO CHK OUT OUR GEAR INDICATION. WE ADVISED THE LEAD F/A OF OUR SITUATION AND TOLD HIM TO PREPARE THE CABIN. CAPT THEN ATTEMPTED TO INFORM PAXS OF OUR SITUATION, BUT THE PA WAS INOP. WHILE BEING RADAR VECTORED IN THE HOLDING PATTERN, THE CAPT'S ADI AND THE STANDBY ATTITUDE INDICATOR BECAME UNRELIABLE. THE CAPT SWITCHED TO 'BOTH ON 2' ON THE ATTITUDE SELECTOR SWITCH ON THE FORWARD OVERHEAD PANEL. WE ADVISED APCH CTL TO HAVE THE EMER EQUIPMENT STANDING BY. ALSO, WE NOTICED THAT THE N, AND EGT INDICATIONS WERE INOP. WE ATTEMPTED TO RECYCLE THE GEAR, BUT WERE UNABLE TO RAISE THE GEAR HANDLE UP PAST THE OFF POS. USING THE CHKLIST, THE F/O VISUALLY INSPECTED THE NOSE GEAR; THE RED INDICATOR ARROWS SHOWED THAT IT WAS DOWN AND LOCKED. THE F/O THEN WENT BACK INTO THE CAIN TO VISUALLY CHK THE MAIN LNDG GEAR. THE WHEELS APPEARED TO BE DOWN, BUT THE F/O WAS UNABLE TO VERIFY THAT THEY WERE DOWN AND LOCKED WITH THE VIS INDICATORS - THE WHEEL WELL LIGHTS WERE INOP. AFTER VIS INSPECTION OF THE LNDG GEAR, THE FLAPS WERE MOVED TO THE 15 DEG POS TO SEE IF THE GEAR UNSAFE WARNING HORN WOULD SOUND - IT DID NOT, SO WE AGREED THAT IN ALL PROBABILITY THE LNDG GEAR WAS DOWN AND LOCKED. ABOUT THIS TIME WE NOTICED THAT THE ANTISKID INOP LIGHT WAS ON. WE ADVISED APCH CTL THAT WE WANTED TO MAKE A FLYBY AND HAVE THE GEAR VISUALLY CHKED. AFTER THE FLYBY, THE TWR RPTED THAT AN ACFT AT THE APCH END OF RWY 10 RPTED THE NLG AND RMLG APPEARED DOWN, BUT WAS UNSURE ABOUT THE LMLG. AN ARPT VEHICLE RPTED THAT ALL LNDG GEAR APPEARED TO BE DOWN. WE WERE ADVISED BY THE LEAD F/A THAT THE CABIN WAS PREPARED AND PAXS HAD BEEN BRIEFED BY USING THE HAND HELD MEGAPHONE. WE INFORMED THE TWR AND COMPANY OPS OF OUR INTENTION TO LAND. ON LNDG ROLLOUT, NO REVERSER UNLOCKED LIGHTS WERE ILLUMINATED AND THE CAPT WAS UNABLE TO REVERSE THE ENGS. THE ACFT WAS STOPPED USING BRAKES AND SPD BRAKES. AFTER TURNING OFF THE RWY, WE ADVISED THE TWR THAT NO FURTHER ASSISTANCE WAS REQUIRED. WE ALSO INFORMED THE COMPANY THAT WE WANTED TO HAVE THE LNDG GEAR PINNED AND BE TOWED IN TO THE GATE. ABOUT THIS TIME, WE HEARD THE LAV SMOKE DETECTOR SOUND AND THE LEAD F/A ADVISED US THAT THERE WAS SMOKE IN THE CABIN. SMOKE SMELL SEEMED TO BE INCREASING, SO THE CAPT ELECTED TO EMER EVAC THE ACFT AND ADVISED THE LEAD F/A TO DO SO. WE ACCOMPLISHED THE CHKLIST AND ADVISED GND CTL AND THE CRASH FIRE RESCUE CREW OF OUR INTENTIONS. WE EVACUATED THE ACFT VIA THE FORWARD ESCAPE SLIDES. CALLBACK WITH RPTR REVEALED THE FOLLOWING INFO. THE CAUSE OF THE GND SVC BUS FAILURE IS UNKNOWN HOWEVER THE FAILURE APPARENTLY RESULTED IN A CB FIRE THAT SOMEHOW LED TO FAILURE OF THE BATTERY CHARGER AS WELL AS SEVERAL RELAYS IN THE DC ELECTRICAL SYS WHICH MANIFESTED ITSELF NEAR THE APCH PHASE OF THE FLT. FEEDBACK HAS NOT AS OF YET BEEN PROVIDED BY THE ACR SO RPTR IS UNSURE OF THE EXACT PROBS OR REMEDIES. THE SMOKE IN THE ACFT RESULTING IN THE ACFT EVAC WAS CAUSED BY OVERHEATED AC PACKS AND WAS NOT OF ELECTRICAL ORIGIN.

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.