It seems you're asking about a possible military operation called "Sandstone 1948" involving the Air Force at a location called "Fitzwilliam." This information doesn't appear to be readily available in public records or historical archives.

It's possible that:

* The information is classified: Military operations, especially from the early Cold War era, are often classified for security reasons.

* There's a misunderstanding: There might be a typo in the name of the operation or location, or the information you have is incomplete.

* It's a fictional scenario: The information could be from a book, movie, or game.

To find more information, you could try:

* Contacting the US Air Force: They might have records about past operations.

* Searching historical archives: Look for information about military operations in the 1940s.

* Checking online forums or historical research websites: See if anyone else has encountered this information or if it's been discussed elsewhere.

If you can provide more context or details, such as:

* The type of operation (training exercise, bombing mission, etc.)

* Any other names or dates associated with the operation

* Any other information you have about Fitzwilliam

This could help narrow down the search and potentially lead you to the information you're looking for.