On June 5, 2001, the NTSB released a Revised Final Report for United 585, the Boeing 737, which crashed on March 3, 1991, at Colorado Springs, CO. This is a story about a 737 rudder failure, and ultimately re-designed parts, told through UA585 and to remember the 25 souls on board. The original NTSB investigation blamed the “wind” and listed UA585 as one of only three “unsolved” aviation disasters. The truth was always there – but it took ten years to finally receive a revised Final Report from the NTSB.
In March 1991 all I wanted was the truth about the cause of the crash, and a redesigned aircraft, if necessary, to be sure that others did not die because of this fatal flaw. I did not imagine that it would take so many years to have the truth to be public record. I believe that because of the public pressure from a number of people, and deaths of our loved ones, that the truth finally prevailed.
March 23‑24, 1999, the NTSB formally revised the Probable Cause for UA585 to be:
“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.”
United 585 was possibly the first major commercial airline crash with no Public Hearing back in 1992. A meeting was held which tended to blame the wind for the crash.
We thank the NTSB for their diligence and for the extensive revisions to the Revised Final Report.
United 585 Timeline and Documents
- United 585 – Postscript (PDF)
- May 9, 1991 – Cockpit Voice Recorder Investigation members list.
- August 13, 1991 – Letter from International Association of Machinists & Aerospace Workers (PDF) explains the jammed slides in the servo-valve, mentions several write-ups on the yaw damper prior to the crash, and another recent hard over rudder in Chicago (Mack Moore incident). Click here to view document and Parts Catalog Illustrations.
- August 4, 1992 – Letter of Reprimand to United Airlines (PDF) regarding the “Mack Moore” incident, although the UAL mechanics were probably doing the best investigation at that time.
- October 8, 1992 – Minutes from the Boeing “We have a problem” meeting. Boeing met to“Develop 737 Rudder PCU Retrofit Strategy.” The meeting began with: “We have a problem.” They stated that they did not have to ground the fleet, but the needed a retrofit program to fix the 737. It took about 8 years to get this document.
- November 10, 1992 – Letter from Carl W. Vogt, former NTSB Chair, acknowledges the potential for a rudder reversal on all 737’s, thus reporting the true cause of the fatal crash of UA585. This letter and information was withheld for years and finally secured via my three year Freedom of Information request.
View the letter with editorial comment and background information or
view the original letter.
- December 8, 1992 – NTSB cancelled the UA585 Public Hearing and held a “meeting” about UA585, with no testimony under oath, and NTSB wrongly blamed the “wind” for the cause of the cause.
- March, 1996 to January 1997 – NTSB Chair Jim Hall appointed an “Expert Panel” for an independent investigation of the 737 rudder failure, which recommended a redesign of the servo value. This is the only Independent Expert Panel that we know of working on a commercial crash for the NTSB, and it worked very well.
- March 1999 – UA 585 History (PDF)
- March 23‑24 1999 – “USAir 427 and UA585 . . . and the aftermath.” (PDF) NTSB announced a probable cause for US427 and UA585 “737 rudder reversal failures.” Click here