FTW83FU001

The plt had flown the ultralight vehicle to his employer's house & landed in the back yard. During the landing, the vehicle sustained damage which included a bent main landing gear axle, a sheared kingpin bolt & a cracked tail boom to tailmount sleeve. A hardened bolt was purchased at an automotive parts store & partial repairs were made; however, the damage to the tail boom was not detected. The ultralight was preflighted & the plt took off. After circling once & waving, he started on the return flt. Shortly after that, witnesses heard the eng slow or stop as the ultralight pitched nose down into a steep dive & crashed. An exam of the wreckage revealed that the right tail boom tube had separated in flt. During impact, it had penetrated the horizontal stabilizer sail without bending. The left tail boom was bent during impact. A picture of the ultralight (taken before takeoff) revealed that the horizontal stabilizer was slightly angled from the horizontal axis of the ultralight.