Transport Canada CF-2019-15-E (Emergency)

Requires one-time inspection for an improperly installed curvic coupling in the tail rotor, correct any defective conditions, and report any anomalies detected within three days of the inspection. Prompted by a report of a curvic coupling found where the teeth were resting on top of each other instead of meshing together. According to Transport Canada, this errant configuration is vulnerable to loosening of the tail rotor assembly and subsequent vibration and loss of drive to the outboard tail rotor blades that would result in degraded directional control.