Narrative:

On taxi out of msy for takeoff, 'sts' light came on. Recalled 'ess TR' inoperative. Shortly, #1 TR fails, dc-ess and dc ess shed bus become unpwred. #2 TR picks up #2 dc bus, dc bat bus, and #1 dc bus. All radios go dead -- pings -- lower ECAM displaying lots of faults. #3 ramp overhead goes dead. Audio switching does not work. Flagged down b- 757 to call tower. Obtained visual 'ok' to taxi to ramp. Regained audio switching #3 rmp. Called tower and was cleared to taxi to gate. Brakes off, taxi, no nosewheel steering. Stopped aircraft. Mushy brakes. Reset 'anti-skid/nosewheel steering switch' off (about 20 seconds) then on. Tried to taxi. No nosewheel steering. Stopped aircraft again. Mushy brakes. Called operations for tow to gate. ECAM 'hydraulic' page showed good engine pumps, green to top, amber XXXE amber arrow above where psi is shown, appears to have no hydraulic power. Tow arrived and hooked to aircraft. Visual signal to shut down engines. Engine master switches to 'off' engines continue to run and ECAM showed failure of #1 and #2 fuel control valves. Pushed #1 and #2 fire switches. No effect. Engines continued to run. Approximately 2 - 2 1/2 mins engines finally shut down. Arrived at gate. Cfds report hard to obtain and when it came was 18-20 inches long. Mechanic on, tried to reset TR's, could not reset. Finally maintenance found reset in lower electronics bay. Could not access from cockpit. After reset, system repwred and aircraft back to normal. Continued to destination with aircraft operating normal. Areas of concern: 1) far too long for engines to shut down using 'emergency system.' 2) dc ess and dc ess shed busses 'should have priority over' dc main busses. 3) what 'hydraulic' did we really have? 4) cannot reset 'trs' from cockpit. 5) what is on ess dc busses? 6) lost communications for a time. 7) not being able to talk with maintenance for assistance on ground. Callback conversation with reporter revealed the following information: the reporter states he has been flying the A-320 for about 9 months and now has about 500 hours and up until this event has had no problems. The 'sts' light is a status light that alerts the pilot to recall from the ECAM an advisory. In this case the ess TR was inoperative and within about 2 mins the #1 TR failed causing the loss of the ess dc and the ess dc shed bus but the #2 dc bus picked up the bat bus and the #1 dc bus. All normal radios went dead and numerous bells went off indicating the numerous faults displayed on the ECAM were occurring, rmp is the radio mode control panel. The nosewheel steering can be pwred by either of 2 system and switches each time the engines are shut down. A manual reset switch changes the nosewheel steering from one system to the other. In this situation neither hydraulic system would power the nosewheel steering system and the question exists what hydraulics were available if any. When the company gets around to it they plan to take the aircraft off the line to attempt to replicate what happened. As an aside the reporter stated when asked if he noticed long lndgs or floating on automatic lndgs. He said the company had modified their aircraft to correct that problem.

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Original NASA ASRS Text

Title: A-320 LOSES ESS ELECTRICAL BUSSES ON TAXI OUT.

Narrative: ON TAXI OUT OF MSY FOR TKOF, 'STS' LIGHT CAME ON. RECALLED 'ESS TR' INOP. SHORTLY, #1 TR FAILS, DC-ESS AND DC ESS SHED BUS BECOME UNPWRED. #2 TR PICKS UP #2 DC BUS, DC BAT BUS, AND #1 DC BUS. ALL RADIOS GO DEAD -- PINGS -- LOWER ECAM DISPLAYING LOTS OF FAULTS. #3 RAMP OVERHEAD GOES DEAD. AUDIO SWITCHING DOES NOT WORK. FLAGGED DOWN B- 757 TO CALL TWR. OBTAINED VISUAL 'OK' TO TAXI TO RAMP. REGAINED AUDIO SWITCHING #3 RMP. CALLED TWR AND WAS CLRED TO TAXI TO GATE. BRAKES OFF, TAXI, NO NOSEWHEEL STEERING. STOPPED ACFT. MUSHY BRAKES. RESET 'ANTI-SKID/NOSEWHEEL STEERING SWITCH' OFF (ABOUT 20 SECONDS) THEN ON. TRIED TO TAXI. NO NOSEWHEEL STEERING. STOPPED ACFT AGAIN. MUSHY BRAKES. CALLED OPS FOR TOW TO GATE. ECAM 'HYD' PAGE SHOWED GOOD ENG PUMPS, GREEN TO TOP, AMBER XXXE AMBER ARROW ABOVE WHERE PSI IS SHOWN, APPEARS TO HAVE NO HYD PWR. TOW ARRIVED AND HOOKED TO ACFT. VISUAL SIGNAL TO SHUT DOWN ENGS. ENG MASTER SWITCHES TO 'OFF' ENGS CONTINUE TO RUN AND ECAM SHOWED FAILURE OF #1 AND #2 FUEL CTL VALVES. PUSHED #1 AND #2 FIRE SWITCHES. NO EFFECT. ENGS CONTINUED TO RUN. APPROX 2 - 2 1/2 MINS ENGS FINALLY SHUT DOWN. ARRIVED AT GATE. CFDS RPT HARD TO OBTAIN AND WHEN IT CAME WAS 18-20 INCHES LONG. MECH ON, TRIED TO RESET TR'S, COULD NOT RESET. FINALLY MAINT FOUND RESET IN LOWER ELECTRONICS BAY. COULD NOT ACCESS FROM COCKPIT. AFTER RESET, SYS REPWRED AND ACFT BACK TO NORMAL. CONTINUED TO DEST WITH ACFT OPERATING NORMAL. AREAS OF CONCERN: 1) FAR TOO LONG FOR ENGS TO SHUT DOWN USING 'EMER SYS.' 2) DC ESS AND DC ESS SHED BUSSES 'SHOULD HAVE PRIORITY OVER' DC MAIN BUSSES. 3) WHAT 'HYD' DID WE REALLY HAVE? 4) CANNOT RESET 'TRS' FROM COCKPIT. 5) WHAT IS ON ESS DC BUSSES? 6) LOST COMS FOR A TIME. 7) NOT BEING ABLE TO TALK WITH MAINT FOR ASSISTANCE ON GND. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATES HE HAS BEEN FLYING THE A-320 FOR ABOUT 9 MONTHS AND NOW HAS ABOUT 500 HRS AND UP UNTIL THIS EVENT HAS HAD NO PROBS. THE 'STS' LIGHT IS A STATUS LIGHT THAT ALERTS THE PLT TO RECALL FROM THE ECAM AN ADVISORY. IN THIS CASE THE ESS TR WAS INOP AND WITHIN ABOUT 2 MINS THE #1 TR FAILED CAUSING THE LOSS OF THE ESS DC AND THE ESS DC SHED BUS BUT THE #2 DC BUS PICKED UP THE BAT BUS AND THE #1 DC BUS. ALL NORMAL RADIOS WENT DEAD AND NUMEROUS BELLS WENT OFF INDICATING THE NUMEROUS FAULTS DISPLAYED ON THE ECAM WERE OCCURRING, RMP IS THE RADIO MODE CTL PANEL. THE NOSEWHEEL STEERING CAN BE PWRED BY EITHER OF 2 SYS AND SWITCHES EACH TIME THE ENGS ARE SHUT DOWN. A MANUAL RESET SWITCH CHANGES THE NOSEWHEEL STEERING FROM ONE SYS TO THE OTHER. IN THIS SIT NEITHER HYD SYS WOULD PWR THE NOSEWHEEL STEERING SYS AND THE QUESTION EXISTS WHAT HYDS WERE AVAILABLE IF ANY. WHEN THE COMPANY GETS AROUND TO IT THEY PLAN TO TAKE THE ACFT OFF THE LINE TO ATTEMPT TO REPLICATE WHAT HAPPENED. AS AN ASIDE THE RPTR STATED WHEN ASKED IF HE NOTICED LONG LNDGS OR FLOATING ON AUTO LNDGS. HE SAID THE COMPANY HAD MODIFIED THEIR ACFT TO CORRECT THAT PROB.

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.