Individually Owned: 150,657
Corporate Owned: 137,281
Orlando International Airport
Aircraft Accident/Incident Report
Orlando, Florida 32827
Tuesady, December 15, 1998 12:16 EST
NTSB Narrative Summary Released at Completion of Accident
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.
NTSB Probable Cause Narrative
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.
Event Information
| Type of Event | Incident |
| Event Date | 12/15/1998 |
| Event Day of the Week | Tuesday |
| Time of Event | 1216 |
| Event Time Zone | Eastern Standard Time |
| Event City | ORLANDO |
| Event State | FLORIDA |
| Event Country | -- |
| Zipcode of the event site | 32827 |
| Event Date Year | 1998 |
| Event Date Month | 12 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | |
| Event Location Longitude | |
| Event Location Airport | ORLANDO INTERNATIONAL |
| Event Location Nearest Airport ID | MCO |
| Indicates whether the acc/inc occurred off or on an airport | On Airport |
| Distance from airport in statute miles | -- |
| Degrees magnetic from airport | -- |
| Airport Elevation | 96 |
| Weather Briefing Completeness | Full |
| Investigator's weather source | Weather Observation Facility |
| Time of the weather observation | 1253 Eastern Standard Time |
| Direction of event from weather observation facility (degrees) | 0 |
| Weather Observation Facility ID | MCO |
| Elevation of weather observation facility | 96 |
| Distance of event from weather observation facility (units?) | 0 |
| Time Zone of the weather observation | EST |
| Lighting Conditions | Day |
| Lowest Ceiling Height | 2800 |
| Lowest Non-Ceiling Height | 0 |
| Sky/Lowest/Cloud Conditions | Unknown |
| Sky Condition for Lowest Ceiling | Overcast |
| Visibility Runway Visual Range (Feet) | 0 |
| Visibility Runway Visual Value (Statute Miles) | 0 |
| Visibility (Statute Miles) | 10 |
| Air Temperature at event time (in degrees celsius) | 16 |
| Dew Point at event time (in degress fahrenheit) | 9 |
| Wind Direction (degrees magnetic) | 310 |
| Variable Wind Indicator | Unknown |
| Wind Speed (knots) | 10 |
| Wind Velocity Indicator | Unknown |
| Wind Gust Indicator | Unknown |
| Wind Gust (knots) | 0 |
| Altimeter Setting at event time (in. Hg) | 29 |
| Density Altitude (feet) | -- |
| Intensity of Precipitation | Unknown |
| METAR weather report | -- |
| Event Highest Injury | None |
| On Ground, Fatal Injuries | 0 |
| On Ground, Minor Injuries | 0 |
| On Ground, Serious Injuries | 0 |
| Injury Total Fatal | -- |
| Injury Total Minor | -- |
| Injury Total None | 56 |
| Injury Total Serious | -- |
| Injury Total All | -- |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 5025 |
| NTSB Notification Source | -- |
| NTSB Notification Date | Dec 15 1998 12:00AM |
| NTSB Notification Time | 1430 |
| Fiche Number and/or location -used to find docket information | IMAGE |
| Date of most recent change to record | Jan 10 2001 10:10AM |
| User who most recently changed record | dbo |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | -- |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N327DL |
| NTSB Number | MIA99IA046 |
| Missing Aircraft Indicator | N |
| Federal Aviation Reg. Part | Part 121: Air Carrier |
| Type of Flight Plan filed | IFR |
| Flight plan Was Activated? | -- |
| Damage | Minor |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | Boeing |
| Aircraft Model | 737-232 |
| Aircraft Series Identifier | 737-232 |
| Aircraft Serial Number | 23099 |
| Certified Max Gross Weight | 119500 |
| Aircraft Category | Airplane |
| Aircraft Registration Class | U.S. Registered/U.S. Soil |
| Aircraft is a homebuilt? | No |
| Flight Crew Seats | -- |
| Cabin Crew Seats | -- |
| Passenger Seats | -- |
| Total number of seats on the aircraft | 124 |
| Number of Engines | 2 |
| Fixed gear or retractable gear | Retractable |
| Aircraft, Type of Last Inspection | Continuous Airworthiness |
| Date of Last Inspection | Dec 10 1998 12:00AM |
| Airframe hours since last inspection | 44 |
| Airframe Hours | 39347 |
| ELT Installed | No |
| ELT Activated | Unknown |
| ELT Aided Location of Event Site | Unknown |
| ELT Type | -- |
| Aircraft Owner Name | WILMINGTON TRUST COMPANY |
| Aircraft Owner Street Address | RODNEY SQUARE NORTH |
| Aircraft Owner City | WILMINGTON |
| Aircraft Owner State | DE |
| Aircraft Owner Country | |
| Aircraft Owner Zipcode | 19890 |
| Operator is an individual? | -- |
| Operator Name | DELTA AIR LINES INC |
| Operator Same as Owner? | No |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | No |
| Operator Street Address | PO BOX 20706 |
| Operator City | ATLANTA |
| Operator State | GA |
| Operator Country | |
| Operator Zip code | 30320 |
| Operator Code | DALA |
| Owner has at least one certificate | Yes - certificate holder |
| Other Operator of large aircraft? | No |
| Certified for Part 133 or 137 Operation | Unknown |
| Operator Certificate Number | -- |
| Indicates whether an air carrier operation was scheduled or not | Scheduled |
| Indicates Domestic or International Flight | Domestic |
| Operator carrying Pax/Cargo/Mail | Passenger/Cargo |
| Type of Flying (Per_Bus / Primary) | Unknown |
| Second Pilot on Board | Yes |
| Departure Point Same as Event | No |
| Departure Airport Code | BOS |
| Departure City | BOSTON |
| Departure State | MA |
| Departure Country | |
| Departure Time | 900 |
| Departure Time Zone | EST |
| Destination Same as Local Flt | crash at destination city |
| Destination Airport Code | MCO |
| Destination City | |
| Destination State | |
| Destination Country | |
| Specific Phase of Flight | -- |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | Dec 20 2002 12:42PM |
| User who most recently changed record | dbo |
| Since inspection or accident | -- |
| Event Location Runway Number and Location | 35 |
| Runway Length | 10000 |
| Runway Width | 150 |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |