NTSB Identification: ATL90IA124.
The docket is stored on NTSB microfiche number 42807.
Scheduled 14 CFR EASTERN AIR LINES, INC.
Incident occurred Thursday, May 31, 1990 in ATLANTA, GA
Probable Cause Approval Date: 12/30/1992
Aircraft: DOUGLAS DC-9-31, registration: N8982E
Injuries: 67 Uninjured.

NTSB investigators used data provided by various sources and may not have traveled in support of this investigation to prepare this aircraft incident report.

SHORTLY AFTER TAKEOFF, THE FLIGHT CREW HEARD A LOUD 'CLUNK', FOLLOWED BY THE RIGHT GENERATOR FALLING OFF LINE. AFTER UNSUCCESSFULLY ATTEMPTING TO RESET THE RIGHT GENERATOR, THE LEFT GENERATOR FELL OFF LINE. AN ATTEMPT TO RESET THE LEFT GENERATOR WAS ALSO UNSUCCESSFUL. THE CREW SELECTED EMERGENCY POWER AND RETURNED TO THE AIRPORT FOR AN UNEVENTFUL LANDING. EXAMINATION OF THE ELECTRICAL SYSTEM AFTER THE INCIDENT REVEALED THAT THE AC CROSS TIE RELAY HAD FAILED IN THE 'CLOSED' POSITION. THIS PREVENTED EITHER GENERATOR FROM BEING PUT BACK ON LINE. BOTH GENERATORS AND ASSOCIATED COMPONENTS WERE EXAMINED AND NO EVIDENCE OF MALFUNCTION OR FAILURE WAS OBSERVED.

The National Transportation Safety Board determines the probable cause(s) of this incident to be:

FAILURE OF THE AC CROSS TIE RELAY, WHICH PREVENTED THE GENERATORS FROM BEING RECONNECTED TO THE ELECTRICAL SYSTEM. A FACTOR IN THE INCIDENT WAS THE LOSS OF THE LEFT GENERATOR IN FLIGHT. FACTORS INCLUDE INADVERTENTLY DISCONNECTING THE LEFT GENERATOR WHILE TROUBLESHOOTING THE RIGHT GENERATOR LOSS.

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