The EU Aviation Safety Agency (EASA) has published an Emergency Airworthiness Directive (AD) regarding AB139 and AW139 helicopters.
An occurrence was reported of excessive play of the bearing installed in an affected part. Subsequent investigation results revealed that the excessive play was due to an incorrect bearing installation, occurred in production.
This condition, if not detected and corrected, could lead to the fracture of the affected part, possibly resulting in failure of the MR pitch link, and consequent loss of control of the helicopter.
To address this potential unsafe condition, Leonardo issued the ASB to provide the list of affected
parts and inspection and re-identification instructions.
For the reason described above, this AD requires a one-time dimensional check of the affected part and, depending on findings, replacement and re-identification of the affected parts.
Source: CAA.