Mantell UFO Incident

January 1948

This early UFO incident, resulting in the plane crash and death of Captain Thomas Mantell, gained widespread attention and was most likely a case of mistaken identity: a classified Skyhook weather balloon.

Sighting and Pursuit

At about 1:20pm on January 7, 1948, multiple people near Maysville, Kentucky called the Kentucky State Highway Patrol to report an unusual object in the sky. The State Highway Patrol called the military police working at Godman Army Air Field in Fort Knox, Kentucky, and the information traveled up the chain of command to the base commander, Colonel Guy F. Hix.

For over an hour, Hix and many other personnel on the base observed the object, which appeared at the time to be motionless in the sky, in the southwesterly direction. Other civilian witnesses in southern Kentucky also reported seeing the object at this time.

At 2:45pm, a group of F-51 Mustang fighter planes flew over the airfield en route to Standiford Field at Louisville, Kentucky, and were asked to investigate the object. Flight leader Captain Thomas Mantell agreed to take a closer look. He made a climbing turn to 15,000 feet and radioed to the tower that the object was "metallic and it is tremendous in size."

At this point, it was reported that two other pilots, Lieutenant A.W. Clements and Lieutenant B.A. Hammond, were also in the vicinity at about 15,000 feet. Military regulation required that oxygen was required above 14,000 feet. Soon after, Hammond radioed back to the airfield that they were abandoning the pursuit. However, Mantell did not respond, and continued to chased the large object. Mantell reportedly did not have oxygen equipment on hand.


Mantell continued to climb to at least 20,000 - 25,000 feet, and by 3:15pm all pilots and the air base had lost visual and radio contact with him. A search was ordered, and shortly after 5:00pm a crash site was identified on a farm near Franklin, Kentucky. A debris field over half a mile was discovered, along with Mantell's body. His watch had stopped at 3:18pm.

Crash Investigation

The Air Force conducted an investigation into the crash, as well as the unidentified object that Mantell was investigating. On the subject of the crash the report concluded:

"Consensus is that Captain Mantell lost consciousness at approximately 25000 feet, the P-51 being trimmed for a maximum climb continued to climb gradually levelling out as increasing altitude caused decrease in power. The aircraft began to fly in reasonably level attitude at about 30000 feet. It then began a gradual turn to the left because of torque, slowly increasing degree of bank as the nose depressed, finally began a spiraling dive which resulted in excessive speeds causing gradual disintegration of aircraft which probably began between 10000 and 20000 feet."

"Since canopy lock was in place after the crash, it is assumed that Captain Mantell made no attempt to abandon the aircraft, and was unconscious at moment of crash or had died from lack of oxygen before aircraft began spiraling dive from about 30000 feet."

"Parts of the aircraft were found as far as six-tenths (estimated) of a mile from central wreckage. The parts were scattered north to south. The aircraft came straight down in a horizontal position and landed on the left side. The left wing came off while in the air and landed 100 feet from the central wreckage. The aircraft did not slide forward after contact with the ground."

UFO Investigation

The object that Mantell and the other pilots were investigation was more difficult to explain, and the U.S. Air Force's Project Sign, the first Air Force entity that investigated UFOs, hypothesized that it was a case of mistaken identity, and that the object was a daytime sighting of the planet Venus. However, numerous eyewitness accounts conflicted with this hypothesis. Some witnesses reported that it was large and metallic, while others reported it to be "white and looked like an umbrella." PFC Stanley Oliver was interviewed and reported it to resemble "an ice cream cone topped with red." And Lieutenant Orner stated that "Thru binocs (sic) it appeared partially as parachute with bright sun reflecting from top of the silk, however, there seemed to be some red light around the lower part of it.

Skyhook Balloon Conclusion

In 1952, the Mantell Incident was reinvestigated by USAF Captain Edward Ruppelt, supervisor of Project Blue Book. Ruppelt consulted with Dr. J. Allen Hynek, who had initially put forth - but since walked back - the Venus explanation. Hynek had subsequently proposed that the object may have been a U.S. Navy Skyhook balloon. Starting in the late 1940s, the U.S. Navy had been using high-altitude balloons to conduct atmospheric research. The balloons were about 100 feet in diameter, made of aluminum, and cone-shaped. Called Project Skyhook, this program was still classified at the time and would have been unknown to the pilots and air base personnel at Godman Army Air Field. Multiple witness descriptions of the object, including those of Oliver and Orner above, would be consistent with a Skyhook balloon. It was also later discovered that an astronomer at Vanderbilt University in Nashville, Tennessee, observed a pear-shaped balloon with "cables and a basket attached" between 4:30 - 4:45pm.


The Mantell Incident - Official Statements
Ruppelt, Edward J. The Report On Unidentified Flying Objects. New York: Doubleday & Company, Inc., 1956, First Edition; London: Victor Gollancz, 1956. 2nd, expanded edition New York: Ballantine, 1960.

Official Explanation


Counter Argument

Likely a Skyhook balloon.



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