|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Local Time Of Day||0601 To 1200|
|Locale Reference||atc facility : zzz.artcc|
|Altitude||msl single value : 31000|
|Controlling Facilities||artcc : zzz.artcc|
tracon : zzz1.tracon
|Operator||common carrier : air carrier|
|Make Model Name||B767 Undifferentiated or Other Model|
|Operating Under FAR Part||Part 121|
|Flight Phase||cruise : level|
descent : holding
descent : intermediate altitude
descent : approach
landing : roll
|Route In Use||arrival : on vectors|
|Affiliation||company : air carrier|
|Function||flight crew : captain|
oversight : pic
|Affiliation||company : air carrier|
|Function||flight crew : first officer|
|Anomaly||aircraft equipment problem : critical|
|Independent Detector||aircraft equipment other aircraft equipment : eicas|
other flight crewa
|Resolutory Action||flight crew : declared emergency|
flight crew : diverted to another airport
At FL310, some 3 hours into the flight, we lost the dc standby buss. The loss of this buss brings many EICAS messages and flags, loss of all standby flight instruments along with the loss of autoplt and autothrottles. I notified ATC that we had an electrical problem that we were working through as the relief pilot and first officer, both in the cockpit, the relief pilot having just returned from his crew rest break began running the QRH checklist. It was discovered that the standby dc circuit breaker had tripped. A call to dispatch via satcom and phone patch to company maintenance was made and established. Maintenance did not want to try a reset of the dc standby buss circuit breaker. The dispatcher and I agreed on a divert into ZZZ. ATC clearance was received and we got a lower altitude to increase fuel burn. I also started the APU for the same reason. Flight attendants were notified and I made a PA with a brief explanation of why we would be landing in ZZZ. My first officer, now in the jumpseat, and I had some conflict over which checklists we were supposed to be running. I know we've lost standby dc because all the standby instruments are flagged. Well, he disagrees because the QRH list of items lost does not include anything about leading edge flap asymmetry. We've got the leading edge flap asymmetry EICAS display message, the amber light on the panel adjacent to the flap indicator and an indication of 1 degree of flap. To be clear here, we are at FL310 and the flap handle is in the up position. At this point, I think he went into the manual while the first officer got maintenance back on the line. According to maintenance, the flap indicator is now inoperative and the flaps are going to work normally. On approach, we found that to be exactly opposite. As I deployed the flap handle and slowed, I briefly got into the stick shaker. This occurred at about 6000 ft in day, VFR conditions and was not unexpected, as I was hand-flying and felt the controls becoming mushy. I told ATC we would have to circle a bit and work through an additional problem. Circling around in the ZZZ area haze is not without risk and this could have been avoided with a better checklist. During the descent, it was also discovered that the rudder trim was inoperative. It's not mentioned in the QRH list, but does appear in the manual list. We ran the leading edge flap asymmetry checklist and got the flaps to 15 degrees, in agreement with the flap handle. At this point, I sent the first officer, now playing the part of relief pilot, aft to look out the window to see what we really had. As an aside, we did make use of the electrical cockpit door unlock switch to get him back in the cockpit. As soon as the flaps were past 1 degree probably the flap indicator is again working. The flaps were then lowered to 20 degrees, the landing setting. ATC was great in providing vectors, 2 large race track circles as we prepared for the overweight, flap 20 degree landing. We declared an emergency and told ATC that our primary concern was hot brakes. Another PA was made. I explained the reason for the copilot being sent aft to look at flaps. I had already mentioned that we'd had some electrical problems and now explained that we would be landing at less than full flaps -- which would mean a faster than normal touchdown speed, possible overheating of the brakes and the reason they would see fire trucks standing by. Touchdown was between 170 KTS and 175 KTS at 315500 pounds, autobrakes were at 4 degrees. The left engine reverser failed to operate. It felt like it was electrically locked out and that is not mentioned in either the manual or the QRH list of items expected to fail in the loss of standby dc. This additional and unexpected failure, unlike the others, came at a very critical time. We parked on the taxiway, were met by crash fire rescue equipment and were instructed to start the APU and shut down engines. They could see smoke coming from the wheels and didn't want the brakes parked. I was also told by crash fire rescue equipment that they could quickly cool the brakes and that an evacuate/evacuation was not necessary in their opinion. I agreed and they sprayed the area and extinguished a small fire on the left side. Air carrier personnel were on hand for engine start and we taxied to the gate without further problems. I spoke with ZZZ maintenance the following morning and was told that several items expected to fail with loss of dc standby, items not listed in our manual, or in our QRH -- are in fact listed in their maintenance manual. While the loss of standby dc is certainly a very rare event it happened to this crew at an ideal time and on a beautiful VFR day. I hope this debrief serves as motivation to provide the next crew with more complete information. Callback conversation with reporter revealed the following information: it was found during maintenance on the aircraft that there was a fault between the circuit breaker and the dc standby buss. The breaker was replaced and the aircraft returned to service. During a training session shortly after the event the conditions were duplicated in the simulator with the same results. The training department was aware of one other incidence of the same problem. They agreed that the manual information was probably lacking to some extent but more was provided to the flight crew than exists in the boeing pilot's handbook for the aircraft. The ready access to technical help on the ground is designed to fill the information gap. In this case erroneous information was given reference the flaps and flap indication. It was found that the boeing maintenance manual lists 20 items that are available with the loss of dc standby power. Not on that list was the left thrust reverser which was not available on landing and contributed to the conditions resulting in hot brakes, which were set at an autobrakes deceleration rate of 4 for an overweight landing at 315000 pounds, and the small brake fire. The reporter has 6 yrs experience on the aircraft. He is concerned that the same scenario with a crew with more limited experience and familiarity with the aircraft and with less than the perfect flight conditions he had would not have as successful an outcome. The reporter also credits the company CRM training as being evident and an asset to the crew which is illustrated by the first officer's willingness to raise questions about the procedures being used.
Original NASA ASRS Text
Title: A B767 CREW SUFFERS LOSS OF MULTIPLE SYS, INCLUDING SOME NOT LISTED IN THEIR MANUALS, WHEN DC STANDBY BUSS IS LOST DUE TO AN UNEXPLAINED STANDBY BUSS CIRCUIT BEAKER ACTIVATION.
Narrative: AT FL310, SOME 3 HRS INTO THE FLT, WE LOST THE DC STANDBY BUSS. THE LOSS OF THIS BUSS BRINGS MANY EICAS MESSAGES AND FLAGS, LOSS OF ALL STANDBY FLT INSTS ALONG WITH THE LOSS OF AUTOPLT AND AUTOTHROTTLES. I NOTIFIED ATC THAT WE HAD AN ELECTRICAL PROB THAT WE WERE WORKING THROUGH AS THE RELIEF PLT AND FO, BOTH IN THE COCKPIT, THE RELIEF PLT HAVING JUST RETURNED FROM HIS CREW REST BREAK BEGAN RUNNING THE QRH CHKLIST. IT WAS DISCOVERED THAT THE STANDBY DC CIRCUIT BREAKER HAD TRIPPED. A CALL TO DISPATCH VIA SATCOM AND PHONE PATCH TO COMPANY MAINT WAS MADE AND ESTABLISHED. MAINT DID NOT WANT TO TRY A RESET OF THE DC STANDBY BUSS CIRCUIT BREAKER. THE DISPATCHER AND I AGREED ON A DIVERT INTO ZZZ. ATC CLRNC WAS RECEIVED AND WE GOT A LOWER ALT TO INCREASE FUEL BURN. I ALSO STARTED THE APU FOR THE SAME REASON. FLT ATTENDANTS WERE NOTIFIED AND I MADE A PA WITH A BRIEF EXPLANATION OF WHY WE WOULD BE LNDG IN ZZZ. MY FO, NOW IN THE JUMPSEAT, AND I HAD SOME CONFLICT OVER WHICH CHKLISTS WE WERE SUPPOSED TO BE RUNNING. I KNOW WE'VE LOST STANDBY DC BECAUSE ALL THE STANDBY INSTS ARE FLAGGED. WELL, HE DISAGREES BECAUSE THE QRH LIST OF ITEMS LOST DOES NOT INCLUDE ANYTHING ABOUT LEADING EDGE FLAP ASYMMETRY. WE'VE GOT THE LEADING EDGE FLAP ASYMMETRY EICAS DISPLAY MESSAGE, THE AMBER LIGHT ON THE PANEL ADJACENT TO THE FLAP INDICATOR AND AN INDICATION OF 1 DEG OF FLAP. TO BE CLR HERE, WE ARE AT FL310 AND THE FLAP HANDLE IS IN THE UP POS. AT THIS POINT, I THINK HE WENT INTO THE MANUAL WHILE THE FO GOT MAINT BACK ON THE LINE. ACCORDING TO MAINT, THE FLAP INDICATOR IS NOW INOP AND THE FLAPS ARE GOING TO WORK NORMALLY. ON APCH, WE FOUND THAT TO BE EXACTLY OPPOSITE. AS I DEPLOYED THE FLAP HANDLE AND SLOWED, I BRIEFLY GOT INTO THE STICK SHAKER. THIS OCCURRED AT ABOUT 6000 FT IN DAY, VFR CONDITIONS AND WAS NOT UNEXPECTED, AS I WAS HAND-FLYING AND FELT THE CTLS BECOMING MUSHY. I TOLD ATC WE WOULD HAVE TO CIRCLE A BIT AND WORK THROUGH AN ADDITIONAL PROB. CIRCLING AROUND IN THE ZZZ AREA HAZE IS NOT WITHOUT RISK AND THIS COULD HAVE BEEN AVOIDED WITH A BETTER CHKLIST. DURING THE DSCNT, IT WAS ALSO DISCOVERED THAT THE RUDDER TRIM WAS INOP. IT'S NOT MENTIONED IN THE QRH LIST, BUT DOES APPEAR IN THE MANUAL LIST. WE RAN THE LEADING EDGE FLAP ASYMMETRY CHKLIST AND GOT THE FLAPS TO 15 DEGS, IN AGREEMENT WITH THE FLAP HANDLE. AT THIS POINT, I SENT THE FO, NOW PLAYING THE PART OF RELIEF PLT, AFT TO LOOK OUT THE WINDOW TO SEE WHAT WE REALLY HAD. AS AN ASIDE, WE DID MAKE USE OF THE ELECTRICAL COCKPIT DOOR UNLOCK SWITCH TO GET HIM BACK IN THE COCKPIT. AS SOON AS THE FLAPS WERE PAST 1 DEG PROBABLY THE FLAP INDICATOR IS AGAIN WORKING. THE FLAPS WERE THEN LOWERED TO 20 DEGS, THE LNDG SETTING. ATC WAS GREAT IN PROVIDING VECTORS, 2 LARGE RACE TRACK CIRCLES AS WE PREPARED FOR THE OVERWT, FLAP 20 DEG LNDG. WE DECLARED AN EMER AND TOLD ATC THAT OUR PRIMARY CONCERN WAS HOT BRAKES. ANOTHER PA WAS MADE. I EXPLAINED THE REASON FOR THE COPLT BEING SENT AFT TO LOOK AT FLAPS. I HAD ALREADY MENTIONED THAT WE'D HAD SOME ELECTRICAL PROBS AND NOW EXPLAINED THAT WE WOULD BE LNDG AT LESS THAN FULL FLAPS -- WHICH WOULD MEAN A FASTER THAN NORMAL TOUCHDOWN SPD, POSSIBLE OVERHEATING OF THE BRAKES AND THE REASON THEY WOULD SEE FIRE TRUCKS STANDING BY. TOUCHDOWN WAS BTWN 170 KTS AND 175 KTS AT 315500 LBS, AUTOBRAKES WERE AT 4 DEGS. THE L ENG REVERSER FAILED TO OPERATE. IT FELT LIKE IT WAS ELECTRICALLY LOCKED OUT AND THAT IS NOT MENTIONED IN EITHER THE MANUAL OR THE QRH LIST OF ITEMS EXPECTED TO FAIL IN THE LOSS OF STANDBY DC. THIS ADDITIONAL AND UNEXPECTED FAILURE, UNLIKE THE OTHERS, CAME AT A VERY CRITICAL TIME. WE PARKED ON THE TXWY, WERE MET BY CFR AND WERE INSTRUCTED TO START THE APU AND SHUT DOWN ENGS. THEY COULD SEE SMOKE COMING FROM THE WHEELS AND DIDN'T WANT THE BRAKES PARKED. I WAS ALSO TOLD BY CFR THAT THEY COULD QUICKLY COOL THE BRAKES AND THAT AN EVAC WAS NOT NECESSARY IN THEIR OPINION. I AGREED AND THEY SPRAYED THE AREA AND EXTINGUISHED A SMALL FIRE ON THE L SIDE. ACR PERSONNEL WERE ON HAND FOR ENG START AND WE TAXIED TO THE GATE WITHOUT FURTHER PROBS. I SPOKE WITH ZZZ MAINT THE FOLLOWING MORNING AND WAS TOLD THAT SEVERAL ITEMS EXPECTED TO FAIL WITH LOSS OF DC STANDBY, ITEMS NOT LISTED IN OUR MANUAL, OR IN OUR QRH -- ARE IN FACT LISTED IN THEIR MAINT MANUAL. WHILE THE LOSS OF STANDBY DC IS CERTAINLY A VERY RARE EVENT IT HAPPENED TO THIS CREW AT AN IDEAL TIME AND ON A BEAUTIFUL VFR DAY. I HOPE THIS DEBRIEF SERVES AS MOTIVATION TO PROVIDE THE NEXT CREW WITH MORE COMPLETE INFO. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: IT WAS FOUND DURING MAINT ON THE ACFT THAT THERE WAS A FAULT BTWN THE CIRCUIT BREAKER AND THE DC STANDBY BUSS. THE BREAKER WAS REPLACED AND THE ACFT RETURNED TO SVC. DURING A TRAINING SESSION SHORTLY AFTER THE EVENT THE CONDITIONS WERE DUPLICATED IN THE SIMULATOR WITH THE SAME RESULTS. THE TRAINING DEPT WAS AWARE OF ONE OTHER INCIDENCE OF THE SAME PROB. THEY AGREED THAT THE MANUAL INFO WAS PROBABLY LACKING TO SOME EXTENT BUT MORE WAS PROVIDED TO THE FLT CREW THAN EXISTS IN THE BOEING PLT'S HANDBOOK FOR THE ACFT. THE READY ACCESS TO TECHNICAL HELP ON THE GND IS DESIGNED TO FILL THE INFO GAP. IN THIS CASE ERRONEOUS INFO WAS GIVEN REF THE FLAPS AND FLAP INDICATION. IT WAS FOUND THAT THE BOEING MAINT MANUAL LISTS 20 ITEMS THAT ARE AVAILABLE WITH THE LOSS OF DC STANDBY PWR. NOT ON THAT LIST WAS THE L THRUST REVERSER WHICH WAS NOT AVAILABLE ON LNDG AND CONTRIBUTED TO THE CONDITIONS RESULTING IN HOT BRAKES, WHICH WERE SET AT AN AUTOBRAKES DECELERATION RATE OF 4 FOR AN OVERWEIGHT LNDG AT 315000 LBS, AND THE SMALL BRAKE FIRE. THE RPTR HAS 6 YRS EXPERIENCE ON THE ACFT. HE IS CONCERNED THAT THE SAME SCENARIO WITH A CREW WITH MORE LIMITED EXPERIENCE AND FAMILIARITY WITH THE ACFT AND WITH LESS THAN THE PERFECT FLT CONDITIONS HE HAD WOULD NOT HAVE AS SUCCESSFUL AN OUTCOME. THE RPTR ALSO CREDITS THE COMPANY CRM TRAINING AS BEING EVIDENT AND AN ASSET TO THE CREW WHICH IS ILLUSTRATED BY THE FO'S WILLINGNESS TO RAISE QUESTIONS ABOUT THE PROCS BEING USED.
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.