N8982E Douglas DC-9-31 accident

NTSB ATL90IA124 · 1990-05-31 · ATLANTA, GA · near ATL

Docket — crew, injuries and powerplant

Factual narrative

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.

Probable cause

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. The National Transportation Safety Board determined the probable cause of this accident.

Circumstances

Event type

Incident

Highest injury

None

Weather conditions

Visual Meteorological Cond

Light condition

Day

Sky condition

BKN

Ceiling (ft)

13000

Visibility (sm)

5

Wind direction

70

Wind speed (kt)

3

Temperature (F)

66

Nearest airport

WILLIAM B. HARTSFIELD

Distance from field

0.0

Aircraft

Sequence of events

Findings