Perhaps I've misunderstood one or two elements in this puzzle, but my impression is that it's rather contrived, convoluted and ultimately a bit messy.
It's not clear to me whether the designation is a letter or a letter followed by a number. If the latter I don't see the relevance of the first word, the abbreviation for which is BY.
The preamble asks solvers to make "what is described under the grid" disappear, whereas, as far as I can see, the letters of the word following the designation must disappear if the grid is to lose 32 letters and retain real words. That is not the same thing at all. "What is described" is an aircraft.
Finally the letters to be deleted are just randomly spread throught the grid. That's the messy bit referred to in my opening paragraph.