Date Time ATSB issues Safety Advisory Notice to Robinson R44 helicopter operators following drive train failure The ATSB has released a Safety Advisory Notice to Robinson R44 operators and maintainers highlighting the importance of inspecting the helicopter’s clutch shaft yoke. The Safety Advisory Notice arises from the ATSB’s ongoing investigation into a loss of control and collision with terrain accident involving an R44 that was conducting aerial spraying operations near Clare, South Australia on 22 December 2020, which has identified that fatigue cracking in the clutch shaft forward yoke resulted in the total loss of drive to the main rotor system.