On November 23, 1953, over Lake Superior near the U.S.-Canadian border, an incident known as the Kinross Incident occurred. Radar operators detected an unknown object flying in restricted airspace. In response, a USAF F-89C Scorpion jet piloted by First Lieutenant Felix Moncla Jr., with Second Lieutenant Robert L. Wilson as radar operator, was scrambled from the nearby Kincheloe (Kinross) Air Force Base to investigate.
The jet pursued the object for about 30 minutes, flying at speeds up to 500 miles per hour. Ground Control directed the F-89 as its onboard radar had problems tracking the object, which allegedly kept changing course. Ground Control watched on their radar screen as the two blips, representing the jet and the unknown object, got closer until they merged into a single blip about 70 miles off the Keweenaw Peninsula. The IFF (Identification, Friend or Foe) signal from the F-89 was lost when the blips merged. The single blip continued briefly before vanishing from the radar screen. Attempts to contact the jet were unsuccessful.
Immediately following the disappearance, the USAF reported that the jet "was followed by radar until it merged with an object 70 miles off Keweenaw Point in upper Michigan". This statement was soon retracted. A new official explanation emerged: the radar operator had misread the scope, the mission was successfully completed, and the "UFO" was identified as an off-course Royal Canadian Air Force C-47 aircraft flying from Winnipeg to Sudbury. They suggested the F-89 pilot, Lieutenant Moncla, likely suffered from intense vertigo and crashed into Lake Superior while returning to base.
However, the Royal Canadian Air Force denied that any of their aircraft were off course or were the subject of an interception that night. The crew of the C-47 aircraft reportedly saw no signs of an American aircraft. Furthermore, sources mention conflicting explanations allegedly given to Moncla's widow by different Air Force representatives. The official Project Blue Book file attributed the incident to vertigo and atmospheric conditions, stating the mission was successful. The National Investigations Committee on Aerial Phenomena (NICAP) claimed that mention of the mission was expunged from official records.
Despite extensive search and rescue efforts by both the United States and Canadian Air Forces, no trace of the aircraft or its occupants was ever found. Reports of potential wreckage found years later in 1968 proved unsubstantiated or were not confirmed to be the F-89. A widely circulated claim in 2006 about finding the wreckage alongside a metallic disc was exposed as a hoax.
Prominent UFO writer Donald Keyhoe detailed the incident in his 1955 book The Flying Saucer Conspiracy, portraying the radar merge as a physical collision. Technical analysis suggests that the radar equipment used at the time had a limited resolution (around half a mile for the AN/FPS-3 system), meaning two objects could appear as a single blip when in close proximity without necessarily colliding. It is also noted that the F-89C model had known structural and engine issues and was restricted in performance.
The disappearance remains officially unexplained. The conflicting official accounts, the RCAF's denials, the lack of wreckage, and the unusual radar event contribute to the enduring mystery and have fueled various theories, including those involving Unidentified Flying Objects (UFOs) or Unidentified Anomalous Phenomena (UAPs).