Narrative:

Experienced a left engine generator failure with AC x-tie lockout late at night (MD80). All operating manual checklists were followed and full electrical power was restored in 3-5 mins via the APU generator on the left AC buss. The reason it took that long was we were constantly interrupted and distraction by 2 of our very senior flight attendants pounding on the cockpit door and screaming at us. When the left AC bus is unpwred, all of the cabin lights go out and the cabin-to-cockpit interphone is lost 'emergency dc buss.' nowhere in any of the checklists is there a procedure for restoring interphone communication with an AC power loss. We had to interrupt the emergency procedures to unbolt the door and talk to the flight attendants so we could complete the procedures. The checklists should be updated to include selecting emergency power for a left AC buss failure to re-establish cockpit/cabin communication. Callback conversation with reporter revealed the following information: the reporter stated the primary cause of the loss of the left AC buss power was the left engine driven generator came apart. The reporter said the crew was unable to power the left buss through the x-tie relay which indicated being locked out. The reporter stated the APU was started and pwred the left AC buss normally. The reporter said when the left buss failed the cabin lighting and cockpit to cabin interphone failed. The reporter said the 2 forward cabin attendants being alarmed were pounding on the cockpit door and screaming, interfering with the emergency procedures. The reporter stated the emergency procedures do not cover restoring power to the interphone system and should be added to the checklist. The reporter said maintenance reported on the generator coming apart, but gave no explanation on the x-tie relay failing to close and locking out.

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Original NASA ASRS Text

Title: AN MD80 IN CRUISE AT FL350 IN DARKNESS EXPERIENCED LOSS OF L AC BUSS. ALL CABIN LIGHTING AND CABIN INTERPHONE LOST. CAUSED BY L GENERATOR FAILURE.

Narrative: EXPERIENCED A L ENG GENERATOR FAILURE WITH AC X-TIE LOCKOUT LATE AT NIGHT (MD80). ALL OPERATING MANUAL CHKLISTS WERE FOLLOWED AND FULL ELECTRICAL PWR WAS RESTORED IN 3-5 MINS VIA THE APU GENERATOR ON THE L AC BUSS. THE REASON IT TOOK THAT LONG WAS WE WERE CONSTANTLY INTERRUPTED AND DISTR BY 2 OF OUR VERY SENIOR FLT ATTENDANTS POUNDING ON THE COCKPIT DOOR AND SCREAMING AT US. WHEN THE L AC BUS IS UNPWRED, ALL OF THE CABIN LIGHTS GO OUT AND THE CABIN-TO-COCKPIT INTERPHONE IS LOST 'EMER DC BUSS.' NOWHERE IN ANY OF THE CHKLISTS IS THERE A PROC FOR RESTORING INTERPHONE COM WITH AN AC PWR LOSS. WE HAD TO INTERRUPT THE EMER PROCS TO UNBOLT THE DOOR AND TALK TO THE FLT ATTENDANTS SO WE COULD COMPLETE THE PROCS. THE CHKLISTS SHOULD BE UPDATED TO INCLUDE SELECTING EMER PWR FOR A L AC BUSS FAILURE TO RE-ESTABLISH COCKPIT/CABIN COM. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE PRIMARY CAUSE OF THE LOSS OF THE L AC BUSS PWR WAS THE L ENG DRIVEN GENERATOR CAME APART. THE RPTR SAID THE CREW WAS UNABLE TO PWR THE L BUSS THROUGH THE X-TIE RELAY WHICH INDICATED BEING LOCKED OUT. THE RPTR STATED THE APU WAS STARTED AND PWRED THE L AC BUSS NORMALLY. THE RPTR SAID WHEN THE L BUSS FAILED THE CABIN LIGHTING AND COCKPIT TO CABIN INTERPHONE FAILED. THE RPTR SAID THE 2 FORWARD CABIN ATTENDANTS BEING ALARMED WERE POUNDING ON THE COCKPIT DOOR AND SCREAMING, INTERFERING WITH THE EMER PROCS. THE RPTR STATED THE EMER PROCS DO NOT COVER RESTORING PWR TO THE INTERPHONE SYS AND SHOULD BE ADDED TO THE CHKLIST. THE RPTR SAID MAINT RPTED ON THE GENERATOR COMING APART, BUT GAVE NO EXPLANATION ON THE X-TIE RELAY FAILING TO CLOSE AND LOCKING OUT.

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.