Replacing Clutch Actuator Bracket Rivets In Some R44 And R44 II S/Ns

The FAA has published an Airworthiness Directive (AD) for Robinson R44 and R44 II helicopters with certain serial numbers (S/Ns), for rivets attaching the belt tension clutch actuator brackets to the fan scroll housing.

Reports of failures of these rivets and subsequent failure of the clutch actuator prompted this update to an existing AD.

The original AD was published in June 2024 after five failures of the clutch actuators and the rivets attaching the clutch actuator brackets to the fan scroll housing on the R44 II models. Investigation by Robinson revealed that the failures were caused by excessive vibration of the fan scroll housing attributed to its design, including the size and number of the rivets. Because of their similar design, the AD also applied to the earlier R44 model helicopters.

The AD required the parts involved to be inspected and, if necessary, replacing the fan scroll housing, replacing the brackets and rivets, and adding a horizontal torque stripe to each rivet.

During the comment period, Robinson requested the FAA revise the applicability section to identify that only the riveted brackets be subject to the AD. The company stated that some helicopters within the applicable serial number range had been retrofitted with the latest design installation that uses screws instead of rivets to attach the bracket to the fan scroll housing and should not be covered by this AD.

The FAA agreed and has revised the AD to clarify that only certain riveted brackets are subject to this AD, which takes effect January 7, 2025.

FMI:  www.federalregister.gov/