Boeing 747-151 incident near Seattle, Washington, August 22, 1991
On August 22, 1991 at about 11:04 pm local time, a Boeing 747-151, registered N604US, suffered minor damage in an incident near Seattle, Washington (Seatac airport). It was a flight of an unrecorded kind under scheduled airline rules (Part 121). 11 people had minor injuries; 376 others were unhurt. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
A FIRE IN THE NUMBER 4 ENGINE, RESULTING FROM A FUEL LEAK AT THE MAIN FUEL CONTROL UNIT, DUE TO IMPROPER MAINTENANCE BY UNKNOWN/UNDETERMINED PERSON. THE L5 EMERGENCY EXIT FAILED TO OPERATEE DUE TO A BROKEN PLASTIC PULLEY GUARD IN THE SLIDE RELEASE MECHANISM.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 22, 1991 · about 11:04 pm local time
- Place
- Seattle, Washington · Seatac · map
- Type
- Incident
- Injuries
- 11 people had minor injuries; 376 others were unhurt.
- Weather
- visual conditions (good weather)
- Aircraft
- Boeing 747-151 · all 747-151s on the register
- Registration
- N604US · no longer on the register · serial 19781
- 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 NO 4 ENGINE CAUGHT FIRE DURING CLIMB AFTER TAKEOFF AND THE CREW ACTIVATED THE ENGINE FIRE EXTINGUISHER SYSTEM, DUMPED FUEL, AND RETURNED TO THE ARPT FOR AN EMERGENCY LANDING. THE NO 4 ENGINE FIRE AND A GRASS FIRE AT THE RWY T/D ZONE WERE EXTINGUISHED BY ARPT CFR CREW. AN EMERGENCY EVAC WAS CONDUCTED FROM THE LEFT SIDE AFTER THE ACFT STOPPED ON THE RWY. THE L5 EMERGENCY DOOR AND SLIDE FAILED TO DEPLOY FOR THE EVAC. EXAM OF THE ENGINE REVEALED EVIDENCE OF FUEL LEAK FROM THE MAIN FUEL CONTROL UNIT.
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; single-engine land; single-engine sea; instrument: airplane
- Flight time: 22,700 hours in all; 2,700 in this make and model; 150 in the last 90 days; 50 in the last 30 days
- Medical certificate: Class 1 (valid medical--w/ waivers/lim.)
- Seat: left
The aircraft
- Last inspection: inspection type not recorded; 0 hours since
- Maximum gross weight: 734,000 lb
- Seats: 422
- Landing gear: retractable
- Engine: P&W JT9D-7A (turbofan); 0 hours total
- Operator: Northwest Airlines, INC
The flight
- Departed from: KSEA Seattle WA at 11:00 pm
- Destination: RJAA Tokyo OF
- Flight plan: IFR
- Runway 34R, 11,900 ft by 150 ft
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 220° at 8 knots
- Visibility: 50 statute miles
- Sky: scat at 25,000 ft
- Temperature: 79°F (26°C), dew point 55°F (13°C)
- Altimeter: 30.00 inHg
- Observation at 11:35 pm from SEA
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 21 | |||
| Passengers | 11 | 355 |
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.