An Act of Air Sabotage

Published on October 10, 2012

Today in aviation history, on October 10, 1933, a Boeing 247 flying on the regular New York to Chicago route for United Airlines was destroyed by a bomb that had been loaded into either lavatory or the aft baggage compartment.  The plane, flying at night, was seen at approximately 1,000 feet of altitude when an explosion struck it and the plane subsequently crashed and burned.  The events of that night are the first act of aerial sabotage in aviation history.  Tragically, the crew and passengers are perished, though in those days, with smaller planes, only seven people died.  Incredibly, the case remains unsolved to this day — in fact, it is the oldest cold case in aviation history.

Reviewing the Events

When accident investigators arrived at the crash site, located five miles southwest of Chesterton, Indiana, they found the main body of the plane in a wooded area of a farm owned by James Smiley.  However, the tail of the aircraft had been separated from the rest of the plane and had fallen to the ground three quarters of a mile farther back on the flight path, as if it had been blown off in midair.  One wheel of the plane hung from a nearby tree.  The wing tanks, they noted, had not exploded outward, but had rather suffered some crushing in an inward direction.  While the aforementioned lavatory door bore shrapnel scars on the inside, none appeared on the outside.  Likewise, the cargo compartment was shredded as if from a force from inside.  The main body of the wreck was badly burned.


Captain Tarrant presenting his mother with a plane-shaped bouquet of flowers. Photo Credit: Metropolitan Newsreel Photo from 1933

Eye Witness Reports

Witnessed described seeing an explosion in the air, after which the plane flew on a bit before nosing over and diving into the ground with both engines running.  On impact, the main part of the plane with the passenger cabin erupted into flames.  The captain’s body was thrown clear and later found 50 feet away from the wreck, his face partly burned and scratched.  Farmers who tried to approach the flaming wreck reported that the heat was so intense that they could not approach.  They also said that they could hear some screams and one even reported seeing movement inside, though this may have been an illusion.

The impact force of the crash likely would have instantly killed everyone who may have survived the bomb blast.  Two of the bodies, the United radio operator (Burris) and a Chicago man (Smith) were found a half mile from the main wreck, apparently having been blown out of the airplane by the bomb blast.


Copilot Ruby of United Airlines. Photo Credit: Metropolitan Newsreel Photo of 1933

A Fault in the Aircraft?

The first reports of the incident were vague, reflecting not only the lack of information about what really happened but also the very basic accident investigation skills of that era:

“Coroner Carl Davis of Porter county said today the possibility of a time bomb having wrecked the United Air Lines New York – Chicago plane was under investigation.  The plane fell near here Tuesday night, killing seven persons. Dr. Davis had returned an open verdict holding the cause of the crash was unknown.  He said today, however, he was convinced there was an explosion aboard the plane.  He did not reveal the basis for the inquiry into the possibility of a time bomb having wrecked the air craft.  Further inquiry is also being made, the coroner said, into reports that a gun of high power was in the baggage of Emil Smith of Chicago, one of the passengers. The coroner was informed that Smith, a retired grocer, was returning from New York to Chicago to attend a shoot at the North Shore Gun club.” — Prescott Evening Courier — October 12, 1933

The aircraft that crashed, registered as NC13304 and flying as United Flight No. 23, was a Boeing 247, one of the sleekest and best airliners of its day.  Created by Boeing exclusively for United Airlines, it was far ahead of its time.  The Boeing 247 had flown perfectly with United Airlines for seven years — and United was quick to point out that in service it had logged over 60,000,000 miles.  They also pointed out that both pilots were experienced.  Clearly, the loss of the plane was certainly not due to some manufacturing defect.

Furthermore, the plane had taken off from New York, landed in Cleveland for fuel, then taken off to fly the rest of the way to Chicago, passing over Toledo.  United Airlines provided investigators with news that the pilots had radioed minutes before the explosion that “all was well”.


1933 Newspaper Illustration — possibly from the Chicago Tribune (unconfirmed), which includes some minor errors in the data about the crash.

Definitively a Bombing

Later, investigators found traces of either gun powder or nitroglycerine on parts of the aircraft they studied.  Coupled with the excessive damage observed and outward explosive pattern, it was finally concluded that the plane had been bombed.  Well after the crash, a newspaper carried this tidbit sourced from United Airlines that was based on the investigation of a crime laboratory that had been founded in the wake of Chicago’s St. Valentine’s Day Massacre:

“Dr. Muehlberger’s findings, according to United Air Lines officials, centered upon a piece of blanket, part of the plane’s equipment, and several pieces of the metal surface of the plane. Both had been pierced many times by small bits of metal. Only a high explosive could produce a force great enough to force metal through metal, Dr. Muehlberger said. He turned down the theory of a gas explosion, because, he said, gas expands comparatively slowly and would not produce such terrific force.”

Competitive Evils?

While it is impossible to rule out that other manufacturers may have been potential suspects, i.e., seeking to paint Boeing’s or United’s business in a bad light, that seems unlikely.  First, the ethics of business in those days would have made such actions virtually unthinkable; and second, Douglas had embarked on a new strategy to counter Boeing preeminence.  While Boeing’s strategy was to seek advantage for its own airline, United, by giving it exclusive option to buy the Boeing 247, the Douglas strategy was to offer its DC-2 and later DC-3 aircraft to every airline openly.  This would prove to be successful, catapulting the company into the leading position in the airline class aircraft manufacturing business at the time.  Even United Airlines, in the end, would acquire DC-3s to replace its Boeing 247s.


Photo of the police and wreckage of the main part of the aircraft, taken after the fires have burned out. Photo Credit: From a Chicago Tribune story from 1933

Passengers as Possible Suspects

While today, most people would jump to the conclusion that the bomb must have been carried on board by one of the passengers, in the case of United Flight No. 23, that seems unlikely.  The ten seat passenger compartment that day was unusually empty — only three passengers boarded.  All seemed unlikely suspects:

— Dorothy M. Dwyer, a woman from Arlington, Massachusetts
— Emil Smith, a man from Chicago, Illinois
— Fred (C. F.) Schoendorff, a man from Chicago, Illinois

One by one, they can be addressed and seem most likely innocent.  The first, Dorothy Dwyer, was about to get married and as such, doesn’t seem a likely suspect for a suicide bombing of an airliner.

“A few minutes before 4:30 p. m. one day last week at Newark Airport, United Air Lines’ ten-place transport No. 23, bound for Chicago, taxied up to the passenger depot for loading. The passenger list was unusually small. There was a trim young woman who, flushed with excitement, confided in the pilot that she had missed the previous plane and had to be in Reno next morning ‘to visit her sister.’ (It turned out that she was to be married next day.)” — TIME Magazine, October 23, 1933

Likewise, Emil Smith, though he carried a rifle onto the flight, was not a very likely suspect either.  In fact, a man with a bomb would not likely carry a rifle on board — why do that?  To hijack the plane before blowing it up in midair?  To shoot the pilots so as to cause the plane to crash — why do that when a bomb is on board?  In any case, hijackings would not become popular until many years in the future.  Also, since the bomb appears to have been in the cargo hold behind and beneath the lavatory, it could not be accessed while in flight — thus it was likely triggered based on a timing device alone.

Finally, there is Fred (C. F.) Schoendorff, from Chicago.  At just 28 years old, he was the manager of the apartments division of R. Cooper, Jr., Inc.  He was a respected middle manager in his business and seemed on a good career path.  Police were able to clear him of suspicion — he too was an unlikely suspect.


Photos of Crash Wreckage from the Hammond Times, Hammond, Indiana, October 12, 1933.

The Flight Crew?

The idea that the flight crew bombed the plane themselves seems quite bizarre — put simply, if one of the pilots wanted to crash the plane, he could conceivably overpower the other pilot and then just simply point the nose down.  No bomb is needed.  Likewise, it always amazes me that to this day, pilots are routinely frisked and scanned at airports to be sure that they are not going to hijack their own airplanes — perhaps they might hold a gun to their head and tell themselves what to do?

In any case, one should consider all angles — if even a bit briefly.  Here are the flight crew:

— Captain H. R. Tarrant, Oak Park, Illinois — the pilot (male)
— A. T. Ruby, of Chicago, Illinois — the copilot (male)
— H. R. Burris, of Columbus, Ohio — the radio operator (male)
— Miss Alice Scribner, of Chicago, Illinois — the flight attendant (female)

Of those, only the radio operator and flight attendant seem to be realistic suspects, though it is certainly unlikely that the flight attendant had bomb training or the knowledge to create a timing device for bomb detonation.  Like all flight attendants of those days, she was young (age 25) and single.  She was selected for her looks and personality — as well, she was a trained nurse, one of United’s requirements.  She had just joined the airline and had been flying just one month at the time of the bombing.  Finally, it turned out later that the flight attendant too was getting married.  Her fiance, Evan C. Terp (of Green Bay, Wisconsin), was waiting at the airport in Chicago to greet her on arrival.

Though it remains possible, it seems wrong in every aspect that she would have bombed her own plane — or, if she had, why would she have put the bomb in the cargo hold with a timer?  Why not just store it in her flight bag?  Likewise, at the time, the radio operator was cleared of suspicion, given his background and employment with United Airlines.  No motive for the bombing could be found.  Nothing about any of the crew raised even the least bit of suspicion to investigators.


Coincidentally, the very aircraft that would be bombed, NC13304, was featured on a Chicago postcard in 1932 — see aircraft in flight in lower right corner.

So Who Did It?

To this day, nobody knows.  It seems likely that an extra bag was loaded onto the flight in either New York or Cleveland.  With the destination of Chicago, it was thought that perhaps the explosion was related to some sort of Chicago mafia or New York mafia gangland type activity.  Yet this too was never proven — no leads could be developed that implicated the mafia kingpins of the day.

Likewise, though some considered the possibility of a labor dispute, in fact at the time United was working well and positively with all of it labor unions and workers.  Even the pilots, who a month earlier had threatened a strike because the newer Boeing 247s were faster and would reduce their flight hours, had been recently informed that they would be given bonuses to cover the difference.  Investigators concluded that they could find no problems at all within the airline that could possibly have served as a motive.

The last piece of evidence — if it is even that — was recorded in 1999, just 13 years ago, when an old man named Howard Johnson recalled that he had driven to the scene of the accident in his Ford Model T.  He went on record with a recollection that he had been told something at the time about a stranger in Cleveland that had boarded but then walked off — here are his words, from a report captured in an oral history project run by the Westchester Public Library in northwest Indiana.

“No, I guess it had something to do with some labor racketeer because they said that– It was all rather vague but they said that someone got on the plane in Cleveland and had a suitcase and then they got off and no one saw them take the suitcase off. So that’s no doubt what happened. They just left the bomb on the plane.”

Sadly, to this day, the bombing of United Flight No. 23 remains an unsolved mystery in aviation history.




2 thoughts on “An Act of Air Sabotage

  1. Robert Finch says:

    Twenty-Four years later, another plane was blown up in midflight. The bomber was caught by the FBI when they found that his mother was aboard the plane, and that he had takon out a large insurance policy on her life before planting a bomb in her luggage. I wonder if anyone aboard the Boeing 247 had a large insurance policy issued in their name?

  2. Bill Ellis says:

    I have only just discovered this story, I am still looking into the details but at this moment I feel the clue is the high power rifle and its owner Emil Smith. It is possible if he was a competition shooter that he would reload his own bullets. If he was carrying such items in a metal case with reloading powder and primers such items would detonate. Primers are safe if kept in their protective cardboard box. However, if he had them loose in a screw top tin they could detonate.

    Kind regards,
    Bill Ellis.


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