Death in the Clouds, kind of

Having read Death in the Clouds by Agatha Christie last week I thought I'd watch the Poirot TV adaptation starring David Suchet.  None the first ten to fifteen minutes of the adaptation, which was based in Paris and the French Open tennis tournament, appeared in the book.  The number of plane passengers was cut from eleven to eight; Japp travels to Paris; and on it goes.  None of the changes were necessary.  The book could have been adapted as published.  In particular there was no need to mess with the plot or the dialogue, which Christie excels at.  It's becoming something of a recurring theme for me to lament scriptwriters radically altering stories.  The only I times I can see the merit is to cut the length or to address a flaw.  Neither were required in this case.