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On March 3, 1991, United Flight 585 crashed in Widefield Community Park as it was preparing to land at the Colorado Springs Municipal Airport. All 25 people, 20 passengers and five crew members, died on impact.

Just as the Boeing 737 was leveling off at 1,000 feet off the ground, the plane suddenly flipped to the right, and within nine seconds, the jet accelerated to speeds nearing 250 knots and gravity forces of nearly 4 g before colliding with the ground.

The plane went basically nose-first into a wooded tract of private property that sits between Widefield Community Park and the Widefield Apartments (which were known as the Kokomo Apartments in 1991). Firefighters who were at the scene that morning estimate the distance between where the plane crashed and the apartment building is roughly 100 feet.

Only one person on the ground was injured. Michelle Summerson was an 8-year-old who was walking out of a friend's apartment when the blast from the impact knocked her into a neighbor's front door. She was treated for a concussion and later released from the hospital.

The National Transportation Safety Board (NTSB) spent 22 months trying to determine the cause of the crash. At a meeting in December 1992, they couldn't give a definitive cause. Two possible reasons were investigated: the possibility of the airplane encountering a wind rotor coming off the mountains, or a malfunction of the hydraulics system that operates the rudder. Since there was no conclusive evidence, the official report of United 585's crash was labeled: "unsolved." 

In fact, in that NTSB meeting, Boeing, the manufacturer of the 737, issued this statement as their opinion of the probable cause of the crash: "The airplane encountered with an un-forecast and undetected high vorticity translating rotor near the ground in combination with a rapidly-moving air mass, which has been documented to have been in the area. This encounter at low altitude did not allow sufficient height for recovery."

However, FOX21 contacted the National Air Disaster Alliance Foundation in Washington, D.C. They have documentation on their website of an internal meeting of nearly two dozen Boeing employees with the goal of developing a consensus to present to the vice presidents of the company on how to retrofit the internal mechanisms of the power control unit of the 737 rudder system. Supporting data, according to the documents, was that the servo valve inside the power control unit didn't meet its fail-safe design intent.

Also listed on the documents -- the three fundamental facts to get across to the vice presidents: 

1) We have a problem
2) We don't need to ground the fleet
3) We do need a retrofit program to fix it

FOX21 asked the National Transportation Safety Board if it was aware of this meeting at Boeing in October 1992. Peter Knudson, a spokesman with the NTSB, said the board was not aware of any discussion where Boeing believed the rudder system design did not meet the fail-safe intent. He did not elaborate whether that knowledge would have made a difference in determining the cause in the December 1992 meeting.

FOX21 also asked Boeing to comment on that October 1992 meeting. We received no acknowledgement.

However, we did receive the following statement from Julie O'Donnell with Boeing Commercial Airplanes Communications:

"Boeing is dedicated to the safety of its airplanes and the people who fly on them. In an industry driven by safety, the 737 has set a remarkable standard. Both the Classic and Next-Generation 737 have excellent safety records. More than 6,000 Boeing 737 airplanes are in service worldwide -- more than any other commercial airplane produced. As of December 2010, they have accumulated more than 158 million flights and more than 219 million flight hours -- or more than 25,000 years in the air.

On September 14, 2000, Boeing announced changes to enhance the rudder control system on the 737. The enhancements are in three areas: flight crew procedures, maintenance procedures, and control system design. The design changes were consistent with a U.S. National Transportation Safety Board finding that the rudder system could be made more reliably redundant. The redesigned hardware provides two separate and independent control inputs to the main power control unit, making an already safe plane safer.

The U.S. Federal Aviation Administration mandated these rudder system enhancements in November 2002, to be completed by 2008. In January 2003 Boeing began delivering all 737 production airplanes with the enhancements and made retrofit kits available to the in-service fleet. This process helps ensure that the safety of all the world's commercial jetliners continues at the highest levels."

Those enhancements were announced as a result of an independent study by the Engineering Test and Evaluation Board. That board was comprised of members of the FAA, aircraft manufacturers, and the private sector. At the time, the NTSB said the study's findings confirmed what they had concluded in the investigation of USAir 427 and United 585 -- that the 737 rudder system had numerous potential failure modes that posed a significant risk to the traveling public.

USAir 427 crashed when trying to land at Pittsburgh International Airport on September 8, 1994. All 132 people on board that aircraft died.