EASA 2019-0022

This AD partially retains the requirement of EASA AD 2018-0261-E and requires installation of a thermal strip and monitoring of the tail rotor (TR) duplex bearing condition. The ADs stemmed from an AW169 accident that is still under investigation. While the helicopter was taking off at low forward speed, a loss of yaw control was observed. As a precautionary measure, Leonardo a service bulletin to provide inspection instructions to check the correct installation of the TR servo-actuator and, subsequently for AW189 helicopters, since these have a TR flight control system of similar design to AW169 helicopters. EASA followed with ADs, including requiring inspections of the TR duplex bearing. Since then testing showed that temperature is a reliable parameter to determine functional condition of the bearing and published a bulletin with instructions to install and repetitively inspect a thermal strip as an additional means to monitor the condition of the TR duplex bearing.  This action includes that installation and monitoring.