NTSB Identification: MIA98IA100.
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Scheduled 14 CFR operation of FLAGSHIP AIRLINES (D.B.A. AMERICAN EAGLE )
Incident occurred Tuesday, March 10, 1998 in FORT MYERS, FL
Probable Cause Approval Date: 04/20/2000
Aircraft: Aerospatiale ATR-42-300, registration: N275BC
Injuries: 47 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.
The No. 1 generator failed while in cruise flight. When the flighcrew attempted to reset the No. 1 generator, the No. 2 generator also failed. Attempts to reset either of the generators were unsuccessful and after about 1 minute the main battery failed. The flightcrew switched to the emergency battery and made a precautionary landing. Postlanding examination showed the No. 1 generator had failed due to failure of the field excitation wire lug which was caused by improper installation of the wire. The aircraft was on the second flight since the No. 1 generator was changed. The No. 2 generator operated normally in postlanding tests. The main battery was found to be discharged. The battery was returned to service after charging. After the incident the aircraft continued to discharge the main battery and the engine start switch was found defective causing the main battery to discharge.
The National Transportation Safety Board determines the probable cause(s) of this incident to be: The failure of the No. 1 generator field excitation return wire terminal lug due to improper installation of the field excitation return wire by maintenance personnel; the subsequent failure of the No. 2 generator due to overvoltage, caused by the momentary closure of the No. 1 generator contactor, as a result of the flight crew's attempt to reset the No. 1 generator, while an overvoltage condition existed at its POR, due to the shorted failure of the No. 1 GCU diode CR17; and the rapid failure of the aircraft's main battery, accelerated by its existing depleted condition, following an extended period of inadequate charging, due to a damaged electrical system. Full narrative available
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