Narrative:

At FL370 south of jhw; autoplt and autothrottle disengaged along with left gen off and CSD oil press low lights illuminated. I took immediate control of the aircraft and directed my first officer to run the gen off checklist. This list directed the first officer to the CSD low oil press checklist. While we were running the checklist; I also notice that I had an att flag in my ADI; and a heading flag in my HSI; along with the heading and horizon comparator lights. We attempted to disconnect the CSD to no avail. The left generator was still indicating 115V and off-scale high frequencys. We also noticed that the left CSD oil temperature was climbing into the red band. We started the APU which picked up the left busses; allowing me to regain my ADI and RMI. We attempted to disconnect the CSD again with no effect. At this point I informed center of our problem and contacted dispatch. Dispatch was able to put me thru to maintenance to determine that there was minimal fire hazard associated with being unable to disconnect the CSD. I requested direct routing; informed the flight attendants of our situation; and landed. Callback conversation with reporter revealed the following information: when asked by the analyst if he were aware of the possible fire danger due to the material used in construction of the constant speed drive case; the reporter said he was unaware of the material make up of the constant speed drive and the danger presented by a constant speed drive that cannot be disconnected. Reporter stated that the maintenance controller advised the crew that there was a low probability of fire and recommended continuation of the flight. The quick reference handbook did not address a constant speed drive that would not disconnect. Supplemental information from acn 666049: in cruise over jhw VOR with the captain flying; the 'lgen off' light and the 'CSD oil pressure low' light illuminated. The autoplt disconnected; the captain's attitude and heading flaps appeared. The captain selected CADC both on 2 and autoplt 2. The 'lgen off' light had extinguished during this time. I accomplished the CSD oil pressure low procedure. The APU was started and the left bus was powered properly with the APU gen. The CSD frequency was off scale and CSD oil temperature was rising. I attempted to disconnect the CSD as per the procedure but it would not disconnect. After consulting maintenance control to determine the possibility of fire; the flight was continued to ZZZ without incident. Callback conversation with reporter 666049 revealed the following information: reporter stated he did not understand the hazard that a constant speed drive presented when it failed to disconnect. Reporter stated that he was unaware of the combustible characteristics for the materials used in CSD construction. Reporter stated that the flight manual has no information on action to take on a constant speed drive that will not disconnect. The maintenance controller did not address the option of engine shutdown or divert; and recommended continuing to scheduled destination.

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Original NASA ASRS Text

Title: AN MD80 FLT CREW WAS UNABLE TO DISCONNECT AN ENG CSD AFTER INDICATIONS OF FAILURE. THIS SIT WAS NOT ADDRESSED IN THE ACFT FLT MANUAL AND MAINT CTL RECOMMENDED THE FLT CREW LEAVE THE ENG OPERATING AND CONTINUE TO THE SCHEDULED DEST.

Narrative: AT FL370 S OF JHW; AUTOPLT AND AUTOTHROTTLE DISENGAGED ALONG WITH L GEN OFF AND CSD OIL PRESS LOW LIGHTS ILLUMINATED. I TOOK IMMEDIATE CTL OF THE ACFT AND DIRECTED MY FO TO RUN THE GEN OFF CHKLIST. THIS LIST DIRECTED THE FO TO THE CSD LOW OIL PRESS CHKLIST. WHILE WE WERE RUNNING THE CHKLIST; I ALSO NOTICE THAT I HAD AN ATT FLAG IN MY ADI; AND A HDG FLAG IN MY HSI; ALONG WITH THE HEADING AND HORIZON COMPARATOR LIGHTS. WE ATTEMPTED TO DISCONNECT THE CSD TO NO AVAIL. THE L GENERATOR WAS STILL INDICATING 115V AND OFF-SCALE HIGH FREQS. WE ALSO NOTICED THAT THE L CSD OIL TEMP WAS CLBING INTO THE RED BAND. WE STARTED THE APU WHICH PICKED UP THE L BUSSES; ALLOWING ME TO REGAIN MY ADI AND RMI. WE ATTEMPTED TO DISCONNECT THE CSD AGAIN WITH NO EFFECT. AT THIS POINT I INFORMED CTR OF OUR PROB AND CONTACTED DISPATCH. DISPATCH WAS ABLE TO PUT ME THRU TO MAINT TO DETERMINE THAT THERE WAS MINIMAL FIRE HAZARD ASSOCIATED WITH BEING UNABLE TO DISCONNECT THE CSD. I REQUESTED DIRECT ROUTING; INFORMED THE FLT ATTENDANTS OF OUR SIT; AND LANDED. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: WHEN ASKED BY THE ANALYST IF HE WERE AWARE OF THE POSSIBLE FIRE DANGER DUE TO THE MATERIAL USED IN CONSTRUCTION OF THE CONSTANT SPD DRIVE CASE; THE RPTR SAID HE WAS UNAWARE OF THE MATERIAL MAKE UP OF THE CONSTANT SPD DRIVE AND THE DANGER PRESENTED BY A CONSTANT SPD DRIVE THAT CANNOT BE DISCONNECTED. RPTR STATED THAT THE MAINT CTLR ADVISED THE CREW THAT THERE WAS A LOW PROBABILITY OF FIRE AND RECOMMENDED CONTINUATION OF THE FLT. THE QUICK REFERENCE HANDBOOK DID NOT ADDRESS A CONSTANT SPD DRIVE THAT WOULD NOT DISCONNECT. SUPPLEMENTAL INFO FROM ACN 666049: IN CRUISE OVER JHW VOR WITH THE CAPT FLYING; THE 'LGEN OFF' LIGHT AND THE 'CSD OIL PRESSURE LOW' LIGHT ILLUMINATED. THE AUTOPLT DISCONNECTED; THE CAPT'S ATTITUDE AND HDG FLAPS APPEARED. THE CAPT SELECTED CADC BOTH ON 2 AND AUTOPLT 2. THE 'LGEN OFF' LIGHT HAD EXTINGUISHED DURING THIS TIME. I ACCOMPLISHED THE CSD OIL PRESSURE LOW PROC. THE APU WAS STARTED AND THE L BUS WAS POWERED PROPERLY WITH THE APU GEN. THE CSD FREQ WAS OFF SCALE AND CSD OIL TEMP WAS RISING. I ATTEMPTED TO DISCONNECT THE CSD AS PER THE PROC BUT IT WOULD NOT DISCONNECT. AFTER CONSULTING MAINT CTL TO DETERMINE THE POSSIBILITY OF FIRE; THE FLT WAS CONTINUED TO ZZZ WITHOUT INCIDENT. CALLBACK CONVERSATION WITH RPTR 666049 REVEALED THE FOLLOWING INFO: RPTR STATED HE DID NOT UNDERSTAND THE HAZARD THAT A CONSTANT SPD DRIVE PRESENTED WHEN IT FAILED TO DISCONNECT. RPTR STATED THAT HE WAS UNAWARE OF THE COMBUSTIBLE CHARACTERISTICS FOR THE MATERIALS USED IN CSD CONSTRUCTION. RPTR STATED THAT THE FLT MANUAL HAS NO INFO ON ACTION TO TAKE ON A CONSTANT SPD DRIVE THAT WILL NOT DISCONNECT. THE MAINT CTLR DID NOT ADDRESS THE OPTION OF ENG SHUTDOWN OR DIVERT; AND RECOMMENDED CONTINUING TO SCHEDULED DEST.

Data retrieved from NASA's ASRS site as of January 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.