Piper PA-18-150 (Modified) Super Cub, G-BJIV
The aircraft was being used as a glider tug. During the takeoff run for an aero-tow it experienced a failure within the right landing gear, causing the right wingtip to contact the ground. The pilot released the tow and shut down the engine to avoid damage to the propeller. The aircraft then turned through approximately 270° to the right before coming to rest with no further damage. It was found that a steel bracket reacting the right gear bungee loads had developed a concealed crack, causing the bracket to fail, thereby unloading the bungee and allowing the wheel attachment to migrate upwards. On this aircraft type each main landing gear is equipped with a cable to carry the normal suspension loads should a bungee failure occur. On this occasion, the cable on the right gear unit functioned as designed and was able to carry the support loads following the bracket failure. This limited the wheel travel and prevented extensive damage to the aircraft. It did not, however, prevent the wingtip from contacting the ground.