Boeing 747-122 incident near Denver, Colorado, October 24, 1991
On October 24, 1991 at about 8:00 pm local time, a Boeing 747-122, registered N4719U, was involved in an incident near Denver, Colorado. It was a flight of an unrecorded kind under scheduled airline rules (Part 121). No one was hurt; 280 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
A MALFUNCTION IN THE STABILIZER TRIM CONTROL MODULE.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- October 24, 1991 · about 8:00 pm local time
- Place
- Denver, Colorado · map
- Type
- Incident
- Injuries
- No one was hurt; 280 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Boeing 747-122 · all 747-122s on the register
- Registration
- N4719U · no longer on the register · serial 8019
- Damage
- Not recorded
- Flight
- Flight of an unrecorded kind · scheduled airline rules (Part 121)
The NTSB's narrative final · quoted from the NTSB record
DURING LEVEL OFF AT FLIGHT LEVEL 290, WHILE ON A SCHEDULED INTERNATIONAL PASSENGER FLIGHT FROM SAN FRANCISCO, CALIFORNIA, TO LONDON, ENGLAND, ELEVATOR PITCH CONTROL BECAME ERRATIC AND OSCILLATIONS OF UP TO 1,000 FEET EITHER SIDE OF THE BASE ALTITUDE OCCURRED. THE AUTO PILOT WAS DISCONNECTED, COMMUNICATIONS WITH MAINTENANCE CONTROL WAS HELD, AND THE FLIGHT PROCEEDED TO THE NEAREST AIRPORT WITH RUNWAYS EXCEEDING 10,000 FEET IN LENGTH. AN UNEVENTFUL PRECAUTIONARY LANDING WAS CONDUCTED IN DENVER, COLORADO. STABILIZER TRIM COMPONENTS WERE EXAMINED REVEALING DISCREPENCIES IN THE TRIM MODULE AND ELEVATOR FEEL COMPUTER, DUE TO NORMAL WEAR.
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: 25,000 hours in all
- Medical certificate: Unknown
- Seat: left
The aircraft
- Last inspection: continuous airworthiness programme, January 2, 2000
- Maximum gross weight: 775,000 lb
- Seats: 495
- Landing gear: retractable
- Engine: P&W JT9D (turbofan); 0 hours total
- Operator: United Airlines
The flight
- Departed from: SFO San Francisco CA
- Destination: LHR London
- Flight plan: IFR
- Runway 0
- A second pilot was aboard
Weather at the time
- Light: daylight
- Sky: not recorded; not recorded
- Temperature: 0°F (-18°C), dew point 0°F (-18°C)
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 19 | |||
| Passengers | 261 |
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.