ANC83LU001

A test plt & dealer for the manufacturer inspected the ultralight vehicle & made adjustments prior to making a test flight after it was assembled. He stated that before takeoff, he was having problems setting the carburetor mixture & that the throttle cable was not working well. During earlier taxi tests, the eng ceased operating a number of times. Finally, on the last taxi test, the eng operated at full RPM & he elected to takeoff. After takeoff, the ultralight climbed to about 100 ft AGL, then began to lose power. The plt was unable to glide to a clearing & subsequently crashed into trees. The vehicle remained in the trees & the plt remained secure by his lap belt & shoulder harness. However, after he released his restraint system, he was injured when he fell aprx 40 ft to the ground. The temp & dew point were 40 & 36 deg, respectively. According to icing probability curves, serious icing would have been possible at cruise power. However, icing was not verified. There was no provision for carburetor heat.