Judge Says Wake Vortex Not Cause of Sport-Jet Crash

 - June 29, 2010, 12:00 PM

A U.S. district court ruling on June 17 rejected the claim by plaintiff Excel-Jet that the June 22, 2006, takeoff crash of the experimental single-engine Sport-Jet was caused by wake turbulence. Excel-Jet claimed that an air traffic controller at Colorado Springs Municipal Airport failed to ensure adequate separation between the takeoff of a Dash 8-200 and the Sport-Jet, which, at about 15 feet above the runway, “rolled hard to the left and began to ‘cartwheel’ down the runway,” according to witness statements provided to the NTSB. An expert witness for the government testified that the Sport-Jet lost lift when it tried to climb above ground effect and stalled and that ground effect delivers 400 percent additional lift, according to Sport-Jet president Bob Bornhofen. “I’m not aware of any university that teaches additional lift from ground effect,” he said. “We now have a finding of fact that goes against known aerodynamic principles. There is no additional lift from ground effect.” The Sport-Jet took off 126 seconds after the Dash 8. It rolled to the left and also moved to the left, despite the pilot’s application of right rudder and aileron and a 90-degree crosswind from the left. “How is that possible?” he asked. “Only a vortex can do that.”