I don't ever recall hearing that a U.S. B-52 airplane struck the Empire State Building. Can you point me to an article regarding who, what, why, when and where?
On July 28, 1945, an Army Air Corps B-25 bomber crashed into the 79th floor of the Empire State Building. Fourteen people died and $1 million damage was done to the building.
Amazingly, the structure of the building was not severely damaged. Nonetheless it was front page news in New York City and you might check your local library for old copies of New York daily papers on microfilm.
Here are some additional links:
—The Fact Monster