I am skeptical that AA fire from a submarine would bring down a plane flying at high altitude.
From the link:
"Worst Air Disaster Kills 35" - NY Times Headlines Jan.22, 1943
Must be some other NY Times.
Word of the tragic crash was kept secret until FDR was safely back from the Casablanca Conference a week later.
The conference didn't end until two days after the story was in the news. FDR stopped in Brazil and the West Indies and didn't get back to Washington until at least Jan. 31.