LAKELAND, FL, USA
N301CH
Hiller UH-12C
The pilot was hovering to parking when the helicopter experienced a failure of the tail rotor drive shaft. The pilot attempted a hovering autorotation, hovering he did not apply collective pitch. The helicopter collided with the ground in a right skid low condition and rolled over on its right side. Examination of the tailrotor drive shaft revealed excessive wear on the splines to the upper U-joint and on the splines of the transmission output shaft.
On April 15, 2000, at about 1030 eastern daylight time, a Hiller UH-12C, N301CH, registered to a private owner, operating as a 14 CFR Part 91 personal flight, crashed after experiencing a loss of tail rotor control while hovering to park at the Lakeland-Linder Regional Airport, Lakeland, Florida. Visual meteorological conditions prevailed and no flight plan was filed. The private pilot reported minor injuries. The helicopter sustained substantial damage. The flight originated from Plant City, Florida, about 15 minutes before the accident. The pilot stated he had just landed and was cleared to parking. While hovering at 4 feet, he made a right antitorque pedal turn. He applied left antitorque pedal to stop the turn and the helicopter continued to yaw to the right. He applied left antitorque pedal and closed the throttle. He did not pull collective pitch. The helicopter collided with the ground in a right skid low condition and rolled over on its right side. Examination of the helicopter revealed the tailrotor drive shaft was disconnected from the output spline shaft of the main transmission. The drive shaft was removed from the lower U-joint (Carden joint). One bolt was missing from the attachment of lower joint flange. The splines inside the upper U-joint were extensively worn, to the point of being non existent from the forward end to about 1 inch inside the fork. There was also excessive wear on the splines of the transmission output shaft. For additional information see FAA Aviation Safety Inspector statement.
The disconnection of the tail rotor drive shaft and subsequent lack of tail rotor control. Contributing factors were the worn drive shaft splines and the pilots' failure to apply collective on the touchdown resulting in a hard landing and subsequent roll over.
Source: NTSB Aviation Accident Database
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