LONG BEACH, CA, USA
N5830T
Westland Helicopters 30-100
AT 4,000 FT MSL DIRECTIONAL CONTROL WAS LOST. WITNESSES OBSERVED THE HELICOPTER DESCENDING THROUGH THE LOCALIZED CLOUD LAYER IN A LEFT HIGH-ROTATION TURN, WITH THE PITCH ATTITUDE VARYING & ITS RATE OF DESCENT 'VERY FAST.' THE HELICOPTER THEN COLLIDED WITH HIGH TENSION WIRES. THE T/R SERVO WAS FOUND ATTACHED TO THE VERT STABILIZER MOUNT WITH THE UPPER PORTION OF THE N-DEG-2 LEVER ATTACHED TO IT. THE PITCH CHANGE LEVER FROM THE SERVO TO THE 90-DEG GEARBOX HAD FRACTURED DO TO HIGH CYCLE FATIGUE. THE T/R BLADES CONTAINED COUNTERWEIGHTS WHICH ARE DESIGNED, TOGETHER WITH AERODYNAMIC AIRLOADS, TO ASSIST IN RETURNING THE BLADES TO A NEAR 'NEUTRAL' PITCH IN THE EVENT OF A T/R DRIVE AND/OR PITCH CONTROL LEVER FAILURE.
Source: NTSB Aviation Accident Database
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