Colorado Aviation Accidents & Incidents

On November 29, 2004, at 1236 mountain standard time, a Gulfstream Aerospace G-IV, N420QS, owned by Consolidated International Services LLC., and operated by NJI, Inc., was substantially damaged when it departed the right side of the runway and impacted terrain during landing roll at Eagle County Regional Airport (EGE), Eagle, Colorado. Visual meteorological conditions prevailed at the time of the accident. The airline transport certificated captain, the airline transport certificated first officer, and one flight attendant reported no injuries. An instrument flight rules (IFR) flight plan was filed for the positioning flight being conducted under Title 14 CFR Part 91. The flight originated at San Francisco, California, at 1040.

According to the captain, the airplane touched down on runway 25 at 1,000 feet down the runway. Shortly after the nose wheel touched down, the aircraft experienced an uncommanded divergence to the right. The captain was unable to correct the divergence through rudder input. Approximately 2,800 feet down the runway, skid/scuff marks from the airplane's nose landing gear tires appeared as the airplane began to veer to the right. At approximately 3,900 feet, the airplane departed the right side of the runway. The nose landing gear folded aft, and the airplane's nose and right wing tip struck the terrain. The airplane continued to slide, coming to a stop on the edge of the runway at 4,500 feet. The airplane's forward fuselage was substantially damaged and the outboard right wing leading edge sustained minor damage.

According to data provided by Gulfstream, a slight differential braking pressure of 200 psi was noted on the flight data recorder. The recorded brake pressures were not sufficient to provide any appreciable total or differential braking action. Gulfstream engineering analysis indicated that the aircraft would have remained on the runway had maximum differential braking been applied at the time the flight data recorder captured the brake pressure increase as indicated. Shortly after the incident, Gulfstream issued a letter to operators indicating the use of differential braking as the preferred method to counteract any uncommanded divergence of the nose wheel steering system.

On March 17, 2005, the airplane's nose wheel steering servo valve (p/n 74133-01, s/n 409), was examined on a test stand at Parker to determine if the valve was failing electrically or hydraulically. The valve had previously been removed from another G-IV for reports of a hard right turn upon landing. The valve was initially tested under room temperature conditions and it operated normally. The valve was then cold soaked to minus 70 degrees F., and tested with and without electrical input. The servo valve failed in both configurations. After the valve was warmed up to room temperature, the valve operated normally. This testing confirmed, that at minus 70 degrees F., the unit commanded a full flow output, or "hard over," fr