Narrative:

While at cruise; night; IFR; clear visibility over and overcast layer at FL350; smooth air; with both autoplt and autothrottles on; first officer flying; both crew members first idented a potential electrical problem when first officer pfd and navigation display displayed unusual images -- arcing snakes and flickering thunderstorm lighting. Also uncommanded cabin call bells irregularly 'dinged' in the cabin about 8 times. Then the autoplt and autothrottles came off. The first officer then hand flew the aircraft. I; the first officer; stated that 'I will continue to fly the aircraft while you diagnose the problem.' the first event lasted just a few seconds; problems disappeared then after a few mins; I put the autothrottles and autoplt back on. After about 3 mins of no problems; I idented these items off of the circuit breaker list as all coming from the same bus. Both pilots looked for any 'popped' circuit breakers. None were discovered out. First officer then felt circuit breaker panel which had items that were witnessed as intermittent for warmth -- none were discovered. No irregular indications were seen on any other indicators (generator loads; frequency volts; or CSD). The captain and I thought that we might have an electrical fault on this bus that didn't cause a breaker to 'pop.' 3 mins later; same problems occurred; with the addition of irregular uncommanded cabin call bells going off. Crew again looked for fault source. Captain then saw slight spiking coming from right CSD and slight volt spike coming from right generator. No overtemp was noticed from CSD. Right generator showed increasing voltage so both crew members elected to take the right generator off line. When done so; the left electrical side correctly picked up the right side and initially all system faults/indications were cleared. (At this time there was no AC xtie lock-out or loss of any busses.) we then completed the generator off light illuminated checklist from the QRH. Soon after; further various components were lost; starting on the first officer side: first the autoplt; autothrottles; first officer pfd and navigation display; first officer small spotlights; then first officer airspeed indication and altimeter; then we got aural warning of a stall indication. While now utilizing standby instruments; and still accurate -- matching captain primary flight instruments; I continued to maintain same speed; course and altitude. Quickly soon after; the 'dfgd' and both navigation-GPS went dark. The captain and I then decided that it was apparent that there was more than just a bad right generator that we had taken off line and that we should divert to ZZZ which was our closest safe airport. I spoke to ATC that we were having mechanical electrical problems; were declaring an emergency; wanted heading to ZZZ and were unable to guarantee that we could maintain rvsm. ATC acknowledged; provided a heading and cleared us down to FL270. As we had lost GPS; first officer VOR/obs; our only choice of navigation was the captain obs/VOR which he dialed into ZZZ and headings provided by ATC. The captain and I tried to start the APU; but was unable. The captain called the lead flight attendant via the bell call system but was unable to speak with her as the cockpit-to-cabin intercom was inoperative. After checking the door through the cockpit door small window; he brought her fully inside the cockpit and communicated our situation and ETA to ZZZ. After that; we xferred flying duties to the captain as all the operable primary flight indicators were on his side. At that point the captain leveled at assigned FL270; we recognized hydraulic pressure and fluid levels were normal. As the captain wanted to slow and use slats/flaps; I selected the engine driven hydraulic pump. When the pumps were on and normal pressure and fluid levels were normal; we elected not to use the auxiliary pump as we were concerned it might put an additional load on a faulty right electrical system. We then got WX from ATC; and asked for vectors to the longest runway of those safest to land with airport conditions. As the #2 radio was inoperative; we elected to not try to contact our dispatcher to get redispatched to ZZZ. Things were happening quickly and we still at this point were in IMC; over mountains and apparently continuing to slowly lose instruments/components. After an assigned continued descent by ATC we broke out VFR at about 16000 ft and had a clear visual on the airport. At that point; about 12 mins from airport; we had an aircraft xtie lock-out and loss of a few more busses. Aural warnings again of stall and slat overspd began; with the illumination of the stall vane and pitot static heat annunciators. As it further appeared that it was possible we might lose what electrical components we had still operating; I notified now approach controller that we had the runway in sight and if we lost communications with them that we would continue to land. They; ZZZ approach; acknowledged; cleared us for the visual; stated that there was no traffic near us or in the approach area; and asked us for souls on board and fuel. As our fuel totaling indicators were gone; I used the analog fuel used dials; minus our departure fuel to give them a fuel estimate on board and gave them a passenger with crew total. (Note that we never did not lose the #1 radio throughout the rest of the event.) at about 12000 ft were able to get the APU running; but elected to use it to back up the left generator and not power the right side as we were suspicious that there was a fault on the right side. At about 9000 ft turning final for runway; when doing the 'in-range' checklist we again elected to not operate the auxiliary hydraulic pump as again we were getting adequate hydraulic pressure for both mechanical hydraulic pumps which had normally operated the extended slats and flaps; however; when the captain requested the 'gear down' and I selected the gear handle to down; no audible noise to indicate that the gear had dropped and 3 red gear indication lights illuminated indicating a gear extension failure. The gear did not extend as we would expect. When we selected the auxiliary pump on; the gear properly extended. The last segment of the approach; landing; and taxi to the gate was uneventful and within normal flight performance standards. It was later explained to me by a contract mechanic who attended to our aircraft in ZZZ that what we had was a faulty right generator voltage regulator that although we had; what we both thought; isolated the generator from supplying any electricity to the system by selecting the right generator to off; was still providing residual unregulated electricity to the electrical system causing spikes (which caused the aircraft xtie lockout) and gradual shedding of components. This mechanic was surprised not to see in our QRH; when selecting a generator off; to also disconnect the CSD to prevent such an event. Educate pilots in ground school that although a generator can be taken offline by selecting the generator off switch; that residual electricity can still be generated; causing problems. I also recommend that as part of the generator off QRH checklist; that the CSD should be disconnected. Supplemental information from acn 771312: numerous electrical glitches occurred cyclically like lights and chimes and instruments flickering. It was found that the right generator voltage regulator was faulty causing spikes in the right electrical system. We did not have a procedure for voltage fluctuation in our QRH. Look into a possible procedure for voltage fluctuation that would include disconnecting the CSD to completely eliminate the right generator from the system. Callback conversation with reporter acn 771314 revealed the following information: reporter stated the contract maintenance mechanic; from another carrier; was experienced and seemed to have a good understanding of the aircraft electrical system. Reporter also stated that performing the in-flight disconnect procedure for the engine generator(south) was recently demonstrated on another flight to prevent the electrical frequency spikes that appears to have caused the numerous instrumentation and cockpit to cabin communication failures. Reporter is hopeful that his company will amend the QRH language to include the generator disconnect procedure for situations like the one they had experienced.

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Original NASA ASRS Text

Title: AN MD-80 CAPTAIN AND FIRST OFFICER REPORT ON THE FLICKERING LIGHTS AND MULTIPLE COCKPIT SYSTEM INSTRUMENTATION FAILURES; LATER ATTRIBUTED TO THE R ENG GENERATOR. CREW RECOMMENDS QRH PROCEDURE CHANGE.

Narrative: WHILE AT CRUISE; NIGHT; IFR; CLR VISIBILITY OVER AND OVCST LAYER AT FL350; SMOOTH AIR; WITH BOTH AUTOPLT AND AUTOTHROTTLES ON; FO FLYING; BOTH CREW MEMBERS FIRST IDENTED A POTENTIAL ELECTRICAL PROB WHEN FO PFD AND NAV DISPLAY DISPLAYED UNUSUAL IMAGES -- ARCING SNAKES AND FLICKERING TSTM LIGHTING. ALSO UNCOMMANDED CABIN CALL BELLS IRREGULARLY 'DINGED' IN THE CABIN ABOUT 8 TIMES. THEN THE AUTOPLT AND AUTOTHROTTLES CAME OFF. THE FO THEN HAND FLEW THE ACFT. I; THE FO; STATED THAT 'I WILL CONTINUE TO FLY THE ACFT WHILE YOU DIAGNOSE THE PROB.' THE FIRST EVENT LASTED JUST A FEW SECONDS; PROBS DISAPPEARED THEN AFTER A FEW MINS; I PUT THE AUTOTHROTTLES AND AUTOPLT BACK ON. AFTER ABOUT 3 MINS OF NO PROBS; I IDENTED THESE ITEMS OFF OF THE CIRCUIT BREAKER LIST AS ALL COMING FROM THE SAME BUS. BOTH PLTS LOOKED FOR ANY 'POPPED' CIRCUIT BREAKERS. NONE WERE DISCOVERED OUT. FO THEN FELT CIRCUIT BREAKER PANEL WHICH HAD ITEMS THAT WERE WITNESSED AS INTERMITTENT FOR WARMTH -- NONE WERE DISCOVERED. NO IRREGULAR INDICATIONS WERE SEEN ON ANY OTHER INDICATORS (GENERATOR LOADS; FREQ VOLTS; OR CSD). THE CAPT AND I THOUGHT THAT WE MIGHT HAVE AN ELECTRICAL FAULT ON THIS BUS THAT DIDN'T CAUSE A BREAKER TO 'POP.' 3 MINS LATER; SAME PROBS OCCURRED; WITH THE ADDITION OF IRREGULAR UNCOMMANDED CABIN CALL BELLS GOING OFF. CREW AGAIN LOOKED FOR FAULT SOURCE. CAPT THEN SAW SLIGHT SPIKING COMING FROM R CSD AND SLIGHT VOLT SPIKE COMING FROM R GENERATOR. NO OVERTEMP WAS NOTICED FROM CSD. R GENERATOR SHOWED INCREASING VOLTAGE SO BOTH CREW MEMBERS ELECTED TO TAKE THE R GENERATOR OFF LINE. WHEN DONE SO; THE L ELECTRICAL SIDE CORRECTLY PICKED UP THE R SIDE AND INITIALLY ALL SYS FAULTS/INDICATIONS WERE CLRED. (AT THIS TIME THERE WAS NO AC XTIE LOCK-OUT OR LOSS OF ANY BUSSES.) WE THEN COMPLETED THE GENERATOR OFF LIGHT ILLUMINATED CHKLIST FROM THE QRH. SOON AFTER; FURTHER VARIOUS COMPONENTS WERE LOST; STARTING ON THE FO SIDE: FIRST THE AUTOPLT; AUTOTHROTTLES; FO PFD AND NAV DISPLAY; FO SMALL SPOTLIGHTS; THEN FO AIRSPD INDICATION AND ALTIMETER; THEN WE GOT AURAL WARNING OF A STALL INDICATION. WHILE NOW UTILIZING STANDBY INSTS; AND STILL ACCURATE -- MATCHING CAPT PRIMARY FLT INSTS; I CONTINUED TO MAINTAIN SAME SPD; COURSE AND ALT. QUICKLY SOON AFTER; THE 'DFGD' AND BOTH NAV-GPS WENT DARK. THE CAPT AND I THEN DECIDED THAT IT WAS APPARENT THAT THERE WAS MORE THAN JUST A BAD R GENERATOR THAT WE HAD TAKEN OFF LINE AND THAT WE SHOULD DIVERT TO ZZZ WHICH WAS OUR CLOSEST SAFE ARPT. I SPOKE TO ATC THAT WE WERE HAVING MECHANICAL ELECTRICAL PROBS; WERE DECLARING AN EMER; WANTED HDG TO ZZZ AND WERE UNABLE TO GUARANTEE THAT WE COULD MAINTAIN RVSM. ATC ACKNOWLEDGED; PROVIDED A HDG AND CLRED US DOWN TO FL270. AS WE HAD LOST GPS; FO VOR/OBS; OUR ONLY CHOICE OF NAV WAS THE CAPT OBS/VOR WHICH HE DIALED INTO ZZZ AND HDGS PROVIDED BY ATC. THE CAPT AND I TRIED TO START THE APU; BUT WAS UNABLE. THE CAPT CALLED THE LEAD FLT ATTENDANT VIA THE BELL CALL SYS BUT WAS UNABLE TO SPEAK WITH HER AS THE COCKPIT-TO-CABIN INTERCOM WAS INOP. AFTER CHKING THE DOOR THROUGH THE COCKPIT DOOR SMALL WINDOW; HE BROUGHT HER FULLY INSIDE THE COCKPIT AND COMMUNICATED OUR SITUATION AND ETA TO ZZZ. AFTER THAT; WE XFERRED FLYING DUTIES TO THE CAPT AS ALL THE OPERABLE PRIMARY FLT INDICATORS WERE ON HIS SIDE. AT THAT POINT THE CAPT LEVELED AT ASSIGNED FL270; WE RECOGNIZED HYD PRESSURE AND FLUID LEVELS WERE NORMAL. AS THE CAPT WANTED TO SLOW AND USE SLATS/FLAPS; I SELECTED THE ENG DRIVEN HYD PUMP. WHEN THE PUMPS WERE ON AND NORMAL PRESSURE AND FLUID LEVELS WERE NORMAL; WE ELECTED NOT TO USE THE AUX PUMP AS WE WERE CONCERNED IT MIGHT PUT AN ADDITIONAL LOAD ON A FAULTY R ELECTRICAL SYS. WE THEN GOT WX FROM ATC; AND ASKED FOR VECTORS TO THE LONGEST RWY OF THOSE SAFEST TO LAND WITH ARPT CONDITIONS. AS THE #2 RADIO WAS INOP; WE ELECTED TO NOT TRY TO CONTACT OUR DISPATCHER TO GET REDISPATCHED TO ZZZ. THINGS WERE HAPPENING QUICKLY AND WE STILL AT THIS POINT WERE IN IMC; OVER MOUNTAINS AND APPARENTLY CONTINUING TO SLOWLY LOSE INSTS/COMPONENTS. AFTER AN ASSIGNED CONTINUED DSCNT BY ATC WE BROKE OUT VFR AT ABOUT 16000 FT AND HAD A CLR VISUAL ON THE ARPT. AT THAT POINT; ABOUT 12 MINS FROM ARPT; WE HAD AN ACFT XTIE LOCK-OUT AND LOSS OF A FEW MORE BUSSES. AURAL WARNINGS AGAIN OF STALL AND SLAT OVERSPD BEGAN; WITH THE ILLUMINATION OF THE STALL VANE AND PITOT STATIC HEAT ANNUNCIATORS. AS IT FURTHER APPEARED THAT IT WAS POSSIBLE WE MIGHT LOSE WHAT ELECTRICAL COMPONENTS WE HAD STILL OPERATING; I NOTIFIED NOW APCH CTLR THAT WE HAD THE RWY IN SIGHT AND IF WE LOST COMS WITH THEM THAT WE WOULD CONTINUE TO LAND. THEY; ZZZ APCH; ACKNOWLEDGED; CLRED US FOR THE VISUAL; STATED THAT THERE WAS NO TFC NEAR US OR IN THE APCH AREA; AND ASKED US FOR SOULS ON BOARD AND FUEL. AS OUR FUEL TOTALING INDICATORS WERE GONE; I USED THE ANALOG FUEL USED DIALS; MINUS OUR DEP FUEL TO GIVE THEM A FUEL ESTIMATE ON BOARD AND GAVE THEM A PAX WITH CREW TOTAL. (NOTE THAT WE NEVER DID NOT LOSE THE #1 RADIO THROUGHOUT THE REST OF THE EVENT.) AT ABOUT 12000 FT WERE ABLE TO GET THE APU RUNNING; BUT ELECTED TO USE IT TO BACK UP THE L GENERATOR AND NOT PWR THE R SIDE AS WE WERE SUSPICIOUS THAT THERE WAS A FAULT ON THE R SIDE. AT ABOUT 9000 FT TURNING FINAL FOR RWY; WHEN DOING THE 'IN-RANGE' CHKLIST WE AGAIN ELECTED TO NOT OPERATE THE AUX HYD PUMP AS AGAIN WE WERE GETTING ADEQUATE HYD PRESSURE FOR BOTH MECHANICAL HYD PUMPS WHICH HAD NORMALLY OPERATED THE EXTENDED SLATS AND FLAPS; HOWEVER; WHEN THE CAPT REQUESTED THE 'GEAR DOWN' AND I SELECTED THE GEAR HANDLE TO DOWN; NO AUDIBLE NOISE TO INDICATE THAT THE GEAR HAD DROPPED AND 3 RED GEAR INDICATION LIGHTS ILLUMINATED INDICATING A GEAR EXTENSION FAILURE. THE GEAR DID NOT EXTEND AS WE WOULD EXPECT. WHEN WE SELECTED THE AUX PUMP ON; THE GEAR PROPERLY EXTENDED. THE LAST SEGMENT OF THE APCH; LNDG; AND TAXI TO THE GATE WAS UNEVENTFUL AND WITHIN NORMAL FLT PERFORMANCE STANDARDS. IT WAS LATER EXPLAINED TO ME BY A CONTRACT MECH WHO ATTENDED TO OUR ACFT IN ZZZ THAT WHAT WE HAD WAS A FAULTY R GENERATOR VOLTAGE REGULATOR THAT ALTHOUGH WE HAD; WHAT WE BOTH THOUGHT; ISOLATED THE GENERATOR FROM SUPPLYING ANY ELECTRICITY TO THE SYS BY SELECTING THE R GENERATOR TO OFF; WAS STILL PROVIDING RESIDUAL UNREGULATED ELECTRICITY TO THE ELECTRICAL SYS CAUSING SPIKES (WHICH CAUSED THE ACFT XTIE LOCKOUT) AND GRADUAL SHEDDING OF COMPONENTS. THIS MECH WAS SURPRISED NOT TO SEE IN OUR QRH; WHEN SELECTING A GENERATOR OFF; TO ALSO DISCONNECT THE CSD TO PREVENT SUCH AN EVENT. EDUCATE PLTS IN GND SCHOOL THAT ALTHOUGH A GENERATOR CAN BE TAKEN OFFLINE BY SELECTING THE GENERATOR OFF SWITCH; THAT RESIDUAL ELECTRICITY CAN STILL BE GENERATED; CAUSING PROBS. I ALSO RECOMMEND THAT AS PART OF THE GENERATOR OFF QRH CHKLIST; THAT THE CSD SHOULD BE DISCONNECTED. SUPPLEMENTAL INFO FROM ACN 771312: NUMEROUS ELECTRICAL GLITCHES OCCURRED CYCLICALLY LIKE LIGHTS AND CHIMES AND INSTS FLICKERING. IT WAS FOUND THAT THE R GENERATOR VOLTAGE REGULATOR WAS FAULTY CAUSING SPIKES IN THE R ELECTRICAL SYS. WE DID NOT HAVE A PROC FOR VOLTAGE FLUCTUATION IN OUR QRH. LOOK INTO A POSSIBLE PROC FOR VOLTAGE FLUCTUATION THAT WOULD INCLUDE DISCONNECTING THE CSD TO COMPLETELY ELIMINATE THE R GENERATOR FROM THE SYS. CALLBACK CONVERSATION WITH RPTR ACN 771314 REVEALED THE FOLLOWING INFO: REPORTER STATED THE CONTRACT MAINT MECHANIC; FROM ANOTHER CARRIER; WAS EXPERIENCED AND SEEMED TO HAVE A GOOD UNDERSTANDING OF THE ACFT ELECTRICAL SYSTEM. REPORTER ALSO STATED THAT PERFORMING THE INFLT DISCONNECT PROCEDURE FOR THE ENG GENERATOR(S) WAS RECENTLY DEMONSTRATED ON ANOTHER FLIGHT TO PREVENT THE ELECTRICAL FREQUENCY SPIKES THAT APPEARS TO HAVE CAUSED THE NUMEROUS INSTRUMENTATION AND COCKPIT TO CABIN COMMUNICATION FAILURES. REPORTER IS HOPEFUL THAT HIS COMPANY WILL AMEND THE QRH LANGUAGE TO INCLUDE THE GENERATOR DISCONNECT PROCEDURE FOR SITUATIONS LIKE THE ONE THEY HAD EXPERIENCED.

Data retrieved from NASA's ASRS site as of May 2009 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.