Anti-Torque Control Cable Failure Leads to Hard Landing During Helicopter Training Maneuver (N1348Z)

Incident Description

During a training flight, an instructor was performing a low RPM recovery maneuver when the aircraft began an uncommanded yaw to the right. The instructor attempted to regain control by applying full left anti-torque pedal, but this input had no effect on the yaw. He then lowered the collective, causing the aircraft to touch down hard. The helicopter rebounded and continued to yaw to the right. The instructor applied left cyclic and rolled off the throttle, resulting in a second touchdown.

Inspection Findings

A post-incident inspection revealed that the left anti-torque control cable had separated. A subsequent laboratory examination determined that the cable failure was due to severe wear. The cable had chafed near the bottom of the starter. Investigators noted that the cable was located in an area that could be inspected during a preflight inspection of the aircraft.