Koflavik, Iceland, March 1952March 1952

On March 13, 1952, radar operators at Keflavik Airport in Iceland detected a series of unidentified objects on their ground control approach (GCA) radar scopes. The first object appeared at 0712Z (7:12 a.m. local time) heading roughly north, and a total of six more objects followed at irregular intervals over the next 57 minutes. The last target was spotted at 0809Z heading roughly east-northeast. All objects appeared in the vicinity of the airport's radio range station.

A U.S. Air Force C-47 transport aircraft was practicing approach landings in the area at the time. The GCA radar crew immediately notified the C-47 pilot and instructed him to break his practice pattern, climb to 10,000 feet, and attempt to visually locate and intercept the objects. Despite these efforts, the pilot saw nothing. Poor weather conditions with broken cloud layers made visual sighting impossible, even though the pilot climbed as high as the aircraft could reach.

The radar operators who filed official statements provided conflicting information about the objects' speed. Master Sergeant John W. Kelly, the GCA crew chief, made no mention of the speed in his statement. However, Captain Clyde B. Knipfer, the C-47 pilot, reported that one of the GCA operators told him the objects had crossed the radar scope faster than F-86 fighter jets that the operator had previously tracked, which traveled at over 700 miles per hour. The official incident report estimated the objects' speed at 250 knots and their altitude as above 8,000 feet, though the radar system in use could not directly measure altitude.

The preparing officer noted in his analysis that certain radar phenomena called "ghosts" or "angels" can create false returns on radar scopes. These effects are sometimes identified by the extreme speeds at which they appear to travel. The officer recommended that such targets be treated as potential hostile aircraft until identified. The file does not state a final Air Force conclusion about what caused the radar returns.

This case file comprises 12 pages as held by the National Archives.