The Mystery Explosion of United Airlines Trip 23

United Airlines Trip 23 is a mystery to many. Here we delve into what it was and where.

Special thanks to Dan Kowalksi, contributing writer, who can be found at http://www.dankowalski.com/ 

Just before 9pm on October 10, 1933, the residents of the rural community of Chesterton, Indiana were startled by the sound of a large explosion in the sky followed by the rapid descent of an airplane’s engine. Many people came out of their homes in time to witness a Boeing 247, United Airlines Trip 23, crash into a field and turn into a fireball. Seven people would be killed in this crash which left no survivors. This would be one of America’s first commercial aircraft accidents and before officials could arrive, the accident scene was flooded with spectators and souvenir hunters. A mechanical error was the first suspect for the responsibility for this accident but as investigators dug through the wreckage, it soon became apparent that the incident was caused by a high-power bomb. But who planted it and why will always remain unsolved. 

The Scene of the Accident

When investigators first arrived at the scene that night, their priority was to locate the passengers and determine if there were any survivors. Before the plane crashed, it broke apart with the tail section separating first and the wings detaching from the fuselage during the impact with the ground. According to United Airlines, 7 people (4 passengers and 3 crew) were on board but only five bodies were found in the main crash. The tail section was later located a mile away and the remaining two bodies were found near it, having been sucked out of the airplane during the first explosion. 

Investigators noted that the two corpses and tail section were not burned while the main fuselage was consumed by fire during impact when the fuel ignited. Forensic science was in its infancy 90 years ago and most evidence that wasn’t taken by treasure hunters was soon sold as scrap metal but some samples were sent to Northwestern University Labs in Chicago for analysis.  

Based on analysis of the debris, it was determined that the location of the first explosion was either the lavatory or the blanket compartment, which jutted into the lavatory’s space just above it. From that point, an explosion occurred with a force that pushed everything else in the aircraft away from this epicenter.

During the first days of the investigation, the most likely theory was that fumes from the fuel had somehow leaked into this spot and ignited but further analysis disputed that. All debris near this point was full of holes and contained a material called duralumin. Duralumin is the same material that the aircraft was made from so whatever exploded didn’t just push the immediate area around it as you would see in a low-power explosion caused by an ignited fuel leak. Instead, this was a high-power explosion that caused the metal in the immediate area to shatter with such force that it easily pierced holes through other metal parts of the plane. The most likely material used in this bomb was determined to be nitroglycerine.

It was clear that a “bomb” was placed on the plane by someone but a detonator was not found. 

The Flight

Trip 23’s aircraft arrived in Newark on the afternoon of October 10. An inspection and cleaning were performed by the ground crew where nothing suspicious was found on board and everything seemed in working order except for a flat tire on one of the landing gears. The plane refueled and departed at 4:30 pm. It was scheduled to first stop in Cleveland, then Chicago, and finally finish its cross-country journey in Oakland, California.  

At Newark, only two passengers boarded the plane that could seat up to ten passengers. One was twenty-five-year-old Dorothy M. Dwyer who was flying to meet her recently divorced fiancée in Reno, Nevada so they could get married. She was supposed to be on an earlier flight but missed it due to a flat tire on her car. 

The second passenger was Emil Smith of Chicago. Smith was a former army officer who owned and operated a grocery store with his aunt until 1930 when they sold it. He was unemployed at the time but seemed financially comfortable. He enjoyed spending his time shooting guns and hunting. At the time of the crash, he was 44 years old. 

Mr. Smith arrived at the airfield and was witnessed drinking from a liquor bottle. Ground staff informed him that alcohol was not permitted but he was allowed to check the open bottle in his small suitcase. He then removed a package from his suitcase that was wrapped in paper. Witnesses described it as being about one foot long and five inches in diameter. He took this package aboard the plane with him. 

Cleveland

The plane landed in Cleveland just after 7 pm. They had a twenty-minute layover. Miss Dwyer got off the plane while Mr. Smith decided to stay. The airport staff asked him to come off the plane and he complied while taking his package. The crew was aware of the incident with the liquor bottle and the airport manager spoke with Mr. Smith to gauge if he had been drinking which he did not appear to be. Keep in mind that in October 1933, Prohibition was still in effect.

Here a new pilot, Captain Tarrant took on the duties for this flight. His co-pilot was A.T. Ruby and the stewardess was Alice Scribner. In addition to Mr. Smith and Miss Dwyer, two more passengers joined the flight. Fred Schendorf, a businessman from Chicago, and Warren Burris, a United Airlines employee that was being shuttled to Chicago to crew another flight.

The flight was fifteen minutes behind schedule when it exploded just minutes outside of Chicago. The last radio transmission was at 8:39 and everything was reported as normal. A radio transmission scheduled for 8:59 was never made. 

 The Nitroglycerine: Who, When, and Why?

Once it was established that a bomb had brought down the plane, the FBI needed to solve who brought it on board, when did they do it, and why. Ninety years later we still have not found an explanation that satisfies all three questions. 

The nature of the explosive itself is the most telling. Remnants of a detonator or battery were never recovered so it seems like explosive material was brought aboard the plane without the intention to remotely detonate it at a specific time or place. 

There was much speculation at the time that the bombing was gangland related with the intention to murder a US Attorney who was known to fly with this airline. However, the absence of a controlled detonator combined with the fact that no one from the government was on this flight makes the scenario seem unlikely. 

It’s possible that the incident could have been motivated by terrorism or revenge but no group took credit for the attack. There was also speculation that it could have been sabotaged by airline workers against the management due to labor issues but this idea was rejected by all employees of the airline at all levels. 

When it was brought on board can also not be said for sure. The FBI interviewed anyone who interacted with that plane in the weeks leading up to the explosion, both passengers and crew. On October 10, there was a cleaning crew on board and one of the members said he opened the compartment for the blankets and checked it without finding anything suspicious inside. While it’s possible he might have missed it, it’s also possible and more likely that the nitroglycerine was not in the compartment at that time.  This is an unstable chemical where sudden force could cause an explosion so it seems unlikely that it was there for days or weeks before the ill-fated flight.

Without knowing why the nitroglycerine was there and when it arrived, we are not able to know who exactly put it there.

Mr. Smith’s Package

The FBI file on the case was declassified and made public in 2017. It’s over 300 pages long and shows that the federal gumshoes really hit the pavement on this case exploring all possibilities. One possibility they explored from the beginning was that Mr. Smith’s mysterious package was the source of the explosion. 

Many modern articles about the explosion claim that Smith was dismissed as a suspect because his character seemed reputable and his package was discovered in the wreckage. But I have read through the FBI files and unless I missed something, there was not any mention of the package being recovered or a description of what it was. The FBI could only determine that it was not delivered to him at the Roosevelt Hotel in Manhattan during his October 6th through 10th stay and that he must have purchased it on his own. 

The confusion about the mysterious package could maybe be explained by this. The Boeing 247 had two cargo compartments; one in the front and one in the back. The rear cargo hold on Trip 23 contained the crew’s belongings plus one express mail package for the Associated Press office in Chicago. This package was recovered in the wreckage and it turned out to be photos. The photos had holes in them which were caused when the shards of duralumin were turned into projectiles during the initial explosion. 

There might be pages missing from the FBI files in regards to Mr. Smith. For starters, his family claimed that he left Chicago to go to New York to attend the World Series about two weeks before the crash but the FBI could only account for his time in New York beginning on October 6. There doesn’t seem to be anything in the file to show where he was in the days before that. Nor is there any confirmation that he did attend the World Series or a day by day breakdown of his activities. 

The FBI also tried to eliminate the possibility that Mr. Smith could have purchased explosives on his trip. They point out that in New York City, and the surrounding areas, one can not purchase explosives without identification and a record of it being made. They did concede that it’s possible to travel away from these areas to make unregulated purchases. 

The package was never recovered, identified, or explained in the FBI files. However, investigators interviewed Mr. Smith’s family, friends, and acquaintances. They came to the conclusion that he was a well-liked man of good character and they decided that he was probably not a suspect. Those who saw Mr. Smith on that day described him as charming and cheerful. He certainly did give the appearance as someone planning to blow up a plane and himself with it. 

Why We’ll Never Know

The explosion and crash of United Airlines Trip 23 was the first time a passenger aircraft was destroyed because of a bomb on board. This was the beginning days on commercial air travel during the Great Depression and this incident was unprecedented. There wasn’t a guide book for how to investigate an air crash and the scene was not secured. Pieces of wreckage were stolen by spectators as souvenirs and potential evidence was sold as scrap metal. It wasn’t carefully collected and brought to a warehouse to be reassembled and there wasn’t a Blackbox to record what happened. 

It’s entirely possible that Mr. Smith’s mysterious package was something benevolent and someone took it. Likewise, there could have been a detonator for the bomb and its pieces were taken or completely overlooked. Mr. Smith could have been secretly transporting nitroglycerine and air turbulence caused it to explode. Or someone on the ground might have slipped the bomb on board and have gotten away with it for reasons that we’ll never know. 

Two years of an active investigation with thousands of man power hours weren’t able to uncover why this happened and who was responsible. Ultimately J. Edgar Hoover decided that they exhausted everything they could do to uncover the truth and they closed the file pending any new developments. None ever came. 

Decades later, on the upcoming 80th anniversary of the disaster, amateur historians returned to the site with metal detectors to see if they could find anything the original investigation missed. They recovered scraps of metal that may or may not been from Trip 23’s aircraft.  The exact truth about what happened that night became lost to time at almost the very instant when it happened.

Sources

The FBI Declassified Files

United 23 took off from New Jersey 80 years ago; its midair explosion remains a mystery

80 Years Later, Plane Bombing Remains a Mystery