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April 15, 2000 · Hiller UH-12C · N301CH

Lakeland, FL

Overview

Report Status
Final with probable cause
Event Type
Accident
Date
April 15, 2000
Injury Outcomes
1 injury (1 minor injury)
Location
Lakeland, FL
Aircraft
Hiller UH-12C
Tail Number
N301CH
Operator
Kenneth L Grimes
Injuries
Minor
Aircraft Damage
Substantial
NTSB Number
MIA00LA134

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.

NTSB Probable Cause

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.

Full Narrative

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.

Flight

Event TypeAccident
Event Time10:30 EDT
Nearest Airport0nm
Runway0
Flight Plan FiledNone
Aircraft FireUnknown
Aircraft ExplosionUnknown

Aircraft

AircraftHiller UH-12C
Tail NumberN301CH
Aircraft CategoryHeli
DamageSubstantial
OperatorKenneth L Grimes
Operating RulePart 91
Engine TypeUnknown
Engine DetailsUnknown

People & Injuries

Injury Summary1 injury (1 minor injury)
Fatal0
Serious0
Minor1
Uninjured0
Total1
Crew 1Unknown

Conditions

ConditionsVMC
LightNr
Wind180° @ 6 kt
Visibility12 sm
CeilingOvercast 6000 ft
Temperature / Dew Point70 F
Altimeter30.00 inHg
Observation Time10:50
Weather SourceWFAC

Appendix: Source Data