Some cases of dislodging of lower half scissor spherical bearings Part Number (P/N) 3G6230V00654 have been reported on in-service helicopters. These bearings are installed on main rotor (M/R) Rotating Scissors P/N 3G6230A00733.
As a result of the investigations accomplished by the supplier of the spherical bearings, it was determined that a quality issue might have affected the production of these bearings.
This condition, if not detected and corrected, could lead to loss of control of the helicopter.
To address this potential unsafe condition, AgustaWestland published Alert Bollettino Tecnico (BT) 139-368, providing inspection and replacement instructions.
For the reasons described above, this AD requires repetitive inspections of the M/R Rotating Scissors P/N 3G6230A00733 that have been manufactured or repaired by installing a potentially defective lower half scissor spherical bearing.
This AD also requires replacement of the affected spherical bearings or, as an alternative, replacement of the M/R Rotating Scissors with an affected bearing, which constitutes terminating action for the repetitive inspections required by this AD.
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