Chicago lawyers plane found in Toronto harbour

I heard on the radio that a small plane from Chicago went missing in the fog
during a landing attempt at the Toronto City Centre Airport.
This morning I see in the newspaper that the plane and the pilot have been
located at the bottom of Lake Ontario. The plane was a Beechcraft that could
seat six people.
There has been no known reason, as yet, as to the cause of the crash, according
to the article.
I think this type of crash may be preventable, if it was due to poor visibility, by the
construction of radio signal buoys parallel to the runways lights and a simple
receiver on board light aircraft. Or visible laser beams criss crossing over the runway.
All of this technology is available, is it not?