Boeing 737-291 accident near Colorado Spgs, Colorado, March 3, 1991
On March 3, 1991 at about 4:44 pm local time, a Boeing 737-291, registered N999UA, was destroyed in an accident near Colorado Spgs, Colorado. It was a flight of an unrecorded kind under scheduled airline rules (Part 121). 25 people were killed. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
A loss of control of the airplane resulting from the movement of the rudder surface to its blowdown limit. The rudder surface most likely deflected in a direction opposite to that commanded by the pilots as a result of a jam of the main rudder power control unit servo valve secondary slide to the servo valve housing offset from its neutral position and overtravel of the primary slide.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- March 3, 1991 · about 4:44 pm local time
- Place
- Colorado Spgs, Colorado
- Type
- Accident
- Injuries
- 25 people were killed.
- Weather
- visual conditions (good weather)
- Aircraft
- Boeing 737-291 · all 737-291s on the register
- Registration
- N999UA · no longer on the register · serial 22742
- Damage
- Destroyed
- Flight
- Flight of an unrecorded kind · scheduled airline rules (Part 121)
The NTSB's narrative final · quoted from the NTSB record
Executive Summary On March 3, 1991, a United Airlines (UAL) Boeing 737, registration number N999UA, operating as flight 585, was on a scheduled passenger flight from Denver, Colorado, to Colorado Springs, Colorado. Visual meteorological conditions (VMC) prevailed at the time, and the flight was on an instrument flight rules (IFR) flight plan. Numerous witnesses reported that shortly after completing its turn onto the final approach course to runway 35 at Colorado Springs Municipal Airport (COS), about 0944 Mountain Standard Time, the airplane rolled steadily to the right and pitched nose down until it reached a nearly vertical attitude before hitting the ground in an area known as Widefield Park. The airplane was destroyed, and the 2 flight crewmembers, 3 flight attendants, and 20 passengers aboard were fatally injured.
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, commercial pilot, flight engineer
- Ratings: multi-engine land; single-engine land; instrument: airplane
- Flight time: 9,902 hours in all; 1,732 in this make and model
- Medical certificate: Class 1 (valid medical--w/ waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 26,050 hours
- Last inspection: continuous airworthiness programme, May 27, 1990; 2,046 hours since
- Maximum gross weight: 110,000 lb
- Seats: 105
- Landing gear: retractable
- Engine: P&W JT8D-17 (turbojet); 0 hours total
- Fire on the ground
- Operator: United Airlines
The flight
- Departed from: DEN Denver CO at 4:23 pm
- Flight plan: IFR
- Runway 0
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 330° at 23 knots, gusting 33
- Visibility: 99 statute miles
- Sky: clear
- Temperature: 48°F (9°C), dew point 9°F (-13°C)
- Altimeter: 30.00 inHg
- Observation at 4:50 pm from COS, 3 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 5 | |||
| Passengers | 20 |
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.