Incident · 1998-12-15

What the record says

Event date

1998-12-15

Event type

Incident

Highest injury level

No injuries

Aircraft

Boeing 737-232 (N327DL)

Operating rule

Part 121

Operator

DELTA AIR LINES, INC. Operator named in NTSB report

Operated by (per NTSB report)

DELTA AIR LINES INC

Probable cause

A discharged battery due to a loss of electrolyte, and the latent shorted failures of the No. 1 and 2 generator control unit (GCU) blocking diodes (CR910) for undetermined reasons. These failures resulted in an excessive current drawn from both GCUs, during the flight crew's attempt to start the auxiliary power unit, that caused the immediate overload (opening) of the AC power supply input fuses (POR fuses) internal to each GCU, and subsequent loss of the No.1 and 2 generators; complete discharge of the battery, and subsequent total loss of electrical power. Contributing to the incident was the incorrect reading of the cockpit DC voltmeter (read higher than actual reading) allowing the flight crew to depart with an unreliable (discharged) battery.

Flight crew

Flight-crew details for this event aren't in the NTSB database extract we hold (its coverage starts with 2008 events) — a gap in our data, not an absence of crew.