Question

What do you call it when a plane comes down in garbage heap

Answer 1

It is called "trash landing". :)

This is a show of word play which sounds similar to “crash landing” (trash/crash), crash landing is actually an organized landing made by an airplane because of a crisis containing a fast approaching or continuous danger to the well being and activity of the flying machine, but in this case as the plane land in garbage the word “crash” is replaced by “trash” giving a humorous meaning to the phrase.

Hope this helped :)