Aviation accident LAX05FA229

the in-flight separation of the tail rotor system as a result of a loss of clamp force and fatigue fracturing of the attachment nut plates. The cause of the loss of clamp force was likely due to an inadvertent tail rotor blade strike during the previous landing, which resulted in an imbalance and a high frequency vibration that both induced fatigue in the nut plates and caused one bolt to back out. The pilot's unfamiliarity with the landing area and his poor decision to land with the tail boom facing upstream were factors.