EASA 2020-0187

Requires either a one-time inspection or repetitive inspections, depending on serial numbers, for tail rotor blade fatigue cracks at the blade root draining hole area and any necessary corrective action(s). This AD also requires a one-time dimensional check to verify tail rotor blade conformity and also prohibits rework, repair, or modification of affected parts. Prompted by an accident of an EC130B4 helicopter in which the pilot experienced a sudden onset of vibration and loss of tail rotor control, though he was able to make a successful emergency landing. The initial investigation found that one tail rotor was broken and three others had a crack. All cracks initiated in the draining hole area at the blade root section and have been identified as fatigue cracks. In the same area, geometrical non-conformities were also observed.