EASA 2018-0250-E

An accident occurred on an AW169 helicopter, the root cause of which has not been identified and the technical investigation is still ongoing. While the helicopter was on a takeoff phase at low forward speed, a loss of yaw control has been observed. As a precautionary measure, Leonardo issued ASB 169-120 for AW169 helicopters to provide inspection instructions to check correct installation of the tail rotor (TR) servo-actuator and, subsequently, ASB 189-213 with the same instructions for AW189 helicopters, since these have a TR flight control system of similar design to AW169 helicopters. The incorrect installation of the TR servo-actuator, if not detected and corrected, depending on the flight condition, could possibly result in loss of control of the helicopter. EASA issued AD 2018-0241-E to require a one-time visual inspection of the TR servo-actuator installation and, depending on findings, accomplishment of applicable corrective action(s). The AD also required reporting of inspection results to Leonardo. Since that AD was issued, EASA decided to require an inspection of the TR duplex bearing, as additional precautionary measure. For the reason described above, this AD retains the requirements of EASA AD 2018-0241-E, and requires an inspection of the TR duplex bearing and, depending on findings, accomplishment of applicable corrective action(s).