Official Site of Speaker, Historian and Author Sean Munger

History, Spotlight

The strange case of aircraft NC13304: the 1933 terrorist attack that remains unsolved.

Eighty years ago today, on October 10, 1933, a United Airlines Boeing 247 en route from Cleveland to Chicago, mysteriously exploded over Jackson Township, Indiana. The burning wreckage of the plane fell from the sky into a farmer’s field and nearby woods. All seven passengers and crew aboard the plane died. Witnesses on the ground reported seeing the aircraft explode and burst into flames before it came down.

This was the first fatal crash in the history of United Airlines. Air travel was so new that the flight didn’t even have a flight number; the registration number of the plane was NC13304. As officials investigated, it turned out that the crash of NC13304 was another grim first in aviation history: the first passenger plane to be destroyed in a terrorist attack. Forensic analysis of the wreckage showed that the Boeing 247 was destroyed by a nitroglycerin bomb planted somewhere aboard, probably in the lavatory.

But who did it? And why? The word “terrorism” was unknown in 1933, and before the crash of NC13304, a passenger plane had never before been downed by any form of intentional sabotage, much less a bomb. The paradigm, so familiar to us now, was unknown to investigators in the 1930s. At first the inquiry focused on a mysterious package wrapped in brown paper that someone observed one of the passengers carrying onto the plane. But when that package was found intact in the rubble, it was ruled out as the source of the bomb.

There were simply no clues. If any of the seven who died–including the first stewardess ever killed in the line of duty–had enemies, the police failed to identify them. Certainly no person or group claimed responsibility for the attack. (Terrorists didn’t really do that in 1933 anyway). Everything in the case was simply a dead end.

We do not know who bombed NC13304, or for what purpose. Eighty years later there’s little hope of a resolution in the case. This, the first act of terrorism directed against passengers traveling by air, remains one of the most mysterious.


The image of the Boeing 247, dressed in United Airlines colors from the early 1930s, comes from the Flickr collection of Tom Wigley, and is used under Creative Commons 2.0 (attribution) license.


  1. Sean, every time I see a post I like lately, it’s from you. You must have the same quirky sense of history that I do. Keep it up!

  2. Jeff Bloomfield

    There are many aviation mysteries – just in the 1930s you have the end of the “Hindenburg” (sabotage, accident, act of God), and Amelia Earhart/Fred Noonan disappearing within two months of each other. I can think of several good ones: the death of Italian war hero and military air power pioneer, Marshal Italo Balbo, in 1941 by “friendly fire” (?); the disappearance (in December 1923) of the French zeppelin, “Dixmude” and whether a portion of it’s crew survived; the death of British flying heroine Amy Johnson over the Thames estuary in 1941; the last flight of balloon pioneer John Wise over Lake Michigan in 1879. The last one it is safe to say ended in Wise and a passenger dying, but exactly where and why remain unsettled. Finally another balloon tragedy, the December 1881 disappearance of Walter Powell, Member of Parliament, in a balloon during a violent storm – that story (which I once researched) has been misused by people like Charles Fort to leave us thinking “there are more things in heaven and earth….” etc.

  3. Walter Kappe appears in both. He was the organiser. Kessler’s henchman in Cleveland. Hitler’s henchman in Germany. Did he organise to kill the pilot? Was the pilot a rival or a thorn in Kessler’s plan to turn the Deutsche Zentrale into a Bund?

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