On 7 January 1948 a pilot climbed after a large object reported over Godman Field and died when his aircraft came apart at altitude. It became one of the first UFO cases to enter the official record. This is the record of what happened, not a verdict on what he chased.
On 7 January 1948, personnel at Godman Field, near Fort Knox, Kentucky, reported a large object in the sky. Captain Thomas Mantell, flying a P-51 Mustang, was directed to investigate. He climbed after the object, radioing that it was "metallic and tremendous in size", and continued upward past the altitude at which his unpressurised aircraft could safely operate. He lost consciousness from lack of oxygen; the Mustang went into a descent and broke apart, and Mantell was killed.
What is on the record
The event is documented across twelve document sources, eleven of them primary government records, including US Air Force investigation files, Project Blue Book case files held by the National Archives, and material from the UK National Archives' own UFO files. That density of paperwork is why it grades at the top of the independence ladder here. A twelfth document, a CIA file released under freedom of information, carries a reporting classification rather than a primary one. Base personnel, including Colonel Guy Hicks and the Godman Field tower officers, witnessed parts of the sequence, and other pilots saw parts of it too; the fatality made it a national story. The Air Force attributed the object to a balloon; Keyhoe rejected that explanation along with a proposed sighting of Venus. What Mantell himself described before losing consciousness remains the disputed part of the record.
Why it sits where it does
Mantell grades L4: witness accounts paired with primary government documents from the official inquiry. That is what the top rung records — corroboration by an on-file document, not a ruling on the object. What the record firmly holds is stark: a military pilot climbed after a reported object and died. What he was pursuing, whether a balloon or otherwise, is not something this archive resolves.
