AD/GBK 117/22 - Tail Rotor - Balance Weights

Requires operators of specified Eurocopter BK 117 models to inspect tail-rotor balance weights and control levers per the manufacturer’s Alert Service Bulletin and to replace any parts that exceed the ASB’s damage limits. The Civil Aviation Safety Authority issued the directive; operators bear the cost and scheduling burden (initial check within 2 months or 100 flight‑hours, then recurrent checks at set flight‑hour or calendar intervals). The stated purpose is to prevent thread failure, part separation, severe vibration and potential loss of control.