The EU Aviation Safety Agency (EASA) has published an Emergency Airworthiness Directive regarding Leonardo AB139 and AW139 helicopters.
An occurrence was reported of finding a damaged Tail rotor duplex bearing (TRDB) on an AW139 helicopter. The investigation results determined that the bearing had been removed from a sliding control assembly and reinstalled on another sliding control assembly, even though Aircraft Maintenance Programme procedures do not allow reinstallation of a removed bearing. This condition, if not detected and corrected, could lead to structural failure of an affected part, possibly resulting in loss of control of the helicopter.
To address this potential unsafe condition, Leonardo has issued the Leonardo Emergency Alert Service Bulletin (ASB) 139-725 to provide inspection and replacement instructions.
Source: EASA via CAA.