Boeing 747-251B incident near Los Angeles, California, January 5, 1996
On January 5, 1996 at about 8:30 pm local time, a Boeing 747-251B, registered N628US, suffered minor damage in an incident near Los Angeles, California. It was a flight of an unrecorded kind under scheduled airline rules (Part 121). No one was hurt; 385 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The fatigue fracture of the number 4 bearing oil pressure tube due to an improper maintenance cleaning procedure by company maintenance personnel.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- January 5, 1996 · about 8:30 pm local time
- Place
- Los Angeles, California · map
- Type
- Incident
- Injuries
- No one was hurt; 385 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Boeing 747-251B · all 747-251Bs on the register
- Registration
- N628US · no longer on the register · serial 22389
- Damage
- Minor damage
- Flight
- Flight of an unrecorded kind · scheduled airline rules (Part 121)
The NTSB's narrative final · quoted from the NTSB record
As the aircraft climbed through 11,500 feet msl the number 2 engine sustained an uncontained failure of the low pressure turbine section. Following engine shutdown, the crew dumped 147,000 pounds of fuel and returned to Los Angeles, for an uneventful landing. Postaccident inspection of the aircraft revealed a 2-foot hole in the number 2 engine cowl turbine area at the 9 o'clock position. Minor dents were noted on the number 1 engine cowl, pylon, and the underside of the left wing. Several fan blades from the number 1 engine were found with nicks and leading edge damage. Disassembly of the engine revealed that the oil pressure line to the number 4 bearing had fractured, with evidence of oil spray and fire signatures on the 6th stage low pressure turbine disk. Measurements of the 6th stage disk disclosed disk growth about 1.06 inches over blueprint maximum, which liberated all 6th stage blades from the disk. Metallurgical examination of the tube fracture revealed a fatigue crack through about 25 percent of the tube circumference, with origins at spiral scratches found on the inside diameter of the tube. Periodically the tube must be cleaned of coke build-up. Northwest Airlines and Pratt & Whitney maintenance/overhaul documents relating to the overhaul and cleaning of the number 4 bearing internal pressure tube assembly specify a an oven baking procedure. Cautionary notes state that wire brushes or reamers are not to be used for internal cleaning of the tubes.
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, flight engineer
- Ratings: multi-engine land; single-engine land; instrument: airplane
- Flight time: 12,000 hours in all
- Medical certificate: Class 1 (valid medical--w/ waivers/lim.)
- Seat: left
The aircraft
- Last inspection: continuous airworthiness programme
- Maximum gross weight: 833,000 lb
- Seats: 373
- Landing gear: retractable
- Engine: P&W JT9D-7Q (turbofan); 0 hours total
The flight
- Departed from: LAX at 7:45 pm
- Destination: RJAA Tokyo OF
- Flight plan: IFR
- Runway 0
- A second pilot was aboard
Weather at the time
- Light: daylight
- Visibility: 100 statute miles
- Sky: clear
- Temperature: 0°F (-18°C), dew point 0°F (-18°C)
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 19 | |||
| Passengers | 366 |
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.