19990918027849A

(.4)The empennage assembly of the experimental race plane separated and the aircraft crashed during the first lap of an unlimited class heat race at the Reno national championship air races. The wreckage was spread over approximately a 0.5-mile path. The first item located in the wreckage path was the lower half-span of the rudder control. Approximately 1/8 mile further along the debris path was a wreckage field about 500 feet long containing the remainder of the empennage (including the rudder trim tab), except the rudder upper half-span. The rudder upper half-span, including the mass balance, was located about 1,900 feet to the right of the debris field. When laid together, the rudder exhibited a shredded appearance through the midspan forward of the rudder trim tab location. Review of a spectator video recording taken from the rear in the seconds before the accident showed that, while the other parts of the aircraft were visible, the rudder and vertical stabilizer were not visible. The video technician opined that the disappearance of the vertical fin and rudder might have been the result of 'video smearing' if the rudder was moving rapidly and the video image recorder rat e could not keep up with it. The precipitating event was not determined during extensive reconstruction and analysis of the empennage. (-23)aircraft was participating in the 1999 Reno air race. While in the unlimited gold heat 3A race first lap, aircraft disentigrated while negotiating 1st turn by pylon 1.