Must be something wrong with the main rotor blades.

肯定是主旋翼叶片出了问题。

The clatter of the engine stopped with a final cough, the tail rotor spun briefly in neutral, and the main rotor blades completed a few awkward revolutions and then drooped to a halt.

随着最后一声咳嗽， 发动机的轰鸣声停止了，尾桨短暂地空转，主旋翼叶片笨拙地转了几圈， 然后停了下来。