The second (of five) Ling-Temco-Vought XC-142A VTOL transports, 62-5922, crashes at the Vought facility at NAS Dallas, Texas, while flying at 24 mph at an altitude of 10 to 20 feet, striking the ground first with the port wingtip, then with the starboard wingtip, before making a hard landing.
The wing at the time was at an angle of 45 degrees with the flaps deflected at 60 degrees. Wingtips, ailerons and outboard engine tailpipes are damaged, but crew is uninjured. Recirculated propwash airflow caused by combination of wing tilt and flap deflection produced large erratic aerodynamic disturbances and loss of directional stability. Aircraft is repaired. (Source: Wikipedia)