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Last updated: 28 March 2017
Datum:Sonntag 3 März 1991
Flugzeugtyp:Silhouette image of generic B732 model; specific model in this crash may look slightly different
Boeing 737-291
Fluggesellschaft:United Airlines
Kennzeichen: N999UA
Werknummer: 22742/875
Baujahr: 1982-05-11 (8 years 10 months)
Anzahl Zyklen der Zelle:19734
Triebwerk: 2 Pratt & Whitney JT8D-17
Besatzung:Todesopfer: 5 / Insassen: 5
Fluggäste:Todesopfer: 20 / Insassen: 20
Gesamt:Todesopfer: 25 / Insassen: 25
Sachschaden: Zerstört
Konsequenzen: Written off (damaged beyond repair)
Unfallort:6,4 km (4 Meilen) S of Colorado Springs, CO (   USA)
Flugphase: Annäherung (APR)
Betriebsart:Inländischer planmäßiger Passagierflug
Flug von:Denver-Stapleton International Airport, CO (DEN/KDEN), USA
Flug nach:Colorado Springs-Peterson Field, CO (COS/KCOS), USA
United Airlines flight 585 left Peoria for Colorado Springs, with intermediate stops at Moline, IL and Denver, CO. The aircraft took off from Denver at 09:23 for the last segment of the flight, estimating Colorado Springs at 09:42. The aircraft was cleared for a visual approach to runway 35. The aircraft then suddenly rolled to the right and started to pitch nose down. The crew tried to initiate a go-around by selecting 15-deg. flaps and an increase in thrust. The altitude decreased rapidly, acceleration increased to over 4G until the aircraft struck the ground of Widefield Park almost vertically.
After a 21-month investigation, the NTSB issued a report on the crash in December 1992. In that report, the NTSB said it 'could not identify conclusive evidence to explain the loss of' the aircraft, but indicated that the two most likely explanations were a malfunction of the airplane’s directional control system or an encounter with an unusually severe atmospheric disturbance.

Investigation into a September 1994 crash of a USAir Boeing 737-300 and an loss of control incident on June 9, 1996 (Eastwind Airlines Boeing 737-200), cited a malfunction in the plane’s rudder system as the most likely cause of all three events.

Probable Cause:

PROBABLE CAUSE: "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."

» Aviation Week & Space Technology 11.03.1991 (25-26)
» Flight International 14-21.12.1992 (34)
» NTSB Safety Recommendations A-92-57 and -58
» NTSB/AAR-92/06
» Scramble Vol.13, nr.04
» Scramble 165

Official accident investigation report
investigating agency: National Transport Safety Bureau (NTSB) - United States of America
report status: Final
report number: NTSB/AAR-01-01
report released:27 March 2001
duration of investigation: 10 years
download report: Aircraft Accident Report: Uncontrolled Descent and Collision with Terrain, United Airlines Flight 585, Boeing 737-200, N (NTSB/AAR-01-01)


NTSB issued 24 Safety Recommendations

Show all AD's and Safety Recommendations


photo of Boeing 737-291 N999UA
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This map shows the airport of departure and the intended destination of the flight. The line between the airports does not display the exact flight path.
Distance from Denver-Stapleton International Airport, CO to Colorado Springs-Peterson Field, CO as the crow flies is 109 km (68 miles).

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Boeing 737-200

  • 51st loss
  • 30th Fataler Unfall
  • 1114 built
  • 18th worst accident (Zu diesem Zeitpunkt)
  • 38th worst accident (Momentan)
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