According to a new NTSB report, a dolly remained attached to the plane's tail before takeoff. The two seater glider nose-dived near Wallis last month, killing 68-year-old Fred Blair, his daughter-in-law and her 3-year-old son.
The report states no one noticed the dolly until it was too late.
Aviation experts say the extra weight on the back of the plane made the glider difficult to control.
Last year, Eyewitness News profiled the gliders. About 175 people are members of another high-flying glider club known as The Soaring Club of Houston. That club's fleet consists of 35 of the gliders or sail-planes.
In August, members showed reporter Tom Abrahams how those gliders work like birds. They go up by catching pockets of hot air called thermals. Members spend their weekends in the skies above Fort Bend and Austin counties.