Boeing 737-232 incident near Orlando, Florida, December 15, 1998
On December 15, 1998 at about 5:16 pm local time, a Boeing 737-232, registered N327DL, suffered minor damage in an incident near Orlando, Florida (Orlando International airport). It was a flight of an unrecorded kind under scheduled airline rules (Part 121). No one was hurt; 56 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
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.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- December 15, 1998 · about 5:16 pm local time
- Place
- Orlando, Florida · Orlando International · map
- Type
- Incident
- Injuries
- No one was hurt; 56 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Boeing 737-232 · all 737-232s on the register
- Registration
- N327DL · no longer on the register · serial 23099
- Damage
- Minor damage
- Flight
- Flight of an unrecorded kind · scheduled airline rules (Part 121)
The NTSB's narrative final · quoted from the NTSB record
The auxiliary power unit (APU) was started on base leg. The first officer called for gear and flaps 15. The airplane experienced a total loss of electrical power as the gear and flaps were extended. The APU did not start, and the battery indicated between 17 to 18 volts. Checklist procedures were accomplished and electrical power was unable to be restored. A go-around was initiated, and a subsequent landing was made without further incident. Examination of the electrical system revealed the DC voltmeter in the cockpit was reading 2 volts high. The battery was discharged due to a loss of electrolyte, and there were latent shorted failures of the No. 1 and 2 generator control unit (GCU) blocking diodes. The failure mode of the diodes was not determined. The failures created an excessive current drawn from both GCUs, during the flight crews attempted APU start, immediate overload of the AC power supply input fuses internal to each GCU, loss of the No.1 and 2 generators, complete discharge of the battery, and subsequent total loss of electrical power.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
Pilot
- Certificate: airline transport pilot
- Ratings: multi-engine land; instrument: airplane
- Flight time: 8,000 hours in all; 1,550 in this make and model; 150 in the last 90 days
- Medical certificate: Class 1 (valid medical--no waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 39,347 hours
- Last inspection: continuous airworthiness programme, December 10, 1998; 44 hours since
- Maximum gross weight: 119,500 lb
- Seats: 124
- Landing gear: retractable
- Engine: P&W JT8D-15A (turbofan); 0 hours total
- Operator: Delta Air Lines INC
The flight
- Departed from: BOS Boston MA at 2:00 pm
- Destination: MCO
- Flight plan: IFR
- Runway 35, 10,000 ft by 150 ft
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 310° at 10 knots
- Visibility: 10 statute miles
- Sky: overcast at 2,800 ft; not recorded
- Temperature: 61°F (16°C), dew point 48°F (9°C)
- Altimeter: 29.00 inHg
- Observation at 5:53 pm from MCO
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 5 | |||
| Passengers | 51 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.