this could have been a wire strike. lots of main transmission lines, or whatever your country calls them, have the power lines which are quite big and relatively easy to see (relatively easy, compared to an earth line, because even those big powerlines can disappear...). They can also have an earth line above the powerlines. Those earth lines are far smaller than powerlines, and harder to see, and are above the powerlines.
If you are inexperienced or distracted, you may see the powerlines and focus on them, but then run into the earth line.
and i think that you will find the tail rotor not turning is matching frame rates, etc.