Wheelus radar targets
On the night of 17–18 October 1956, US radar at Wheelus Air Base near Tripoli, Libya, tracked two slow-moving objects for about three hours, and F-86D interceptors locked onto them several times without ever seeing anything.
1956 CE · 32.89, 13.28 · status: disputed
The account
The 633rd Aircraft Control and Warning Squadron saw very bright returns at around 9,000 ft, one of them descending to 3,800 ft, on a clear night. Fighters of the 431st Fighter Interceptor Squadron were scrambled. The file went to Project Blue Book.
The sceptical view
Investigators thought of migrating birds, and a later Air Force review argued that the lack of any visual contact at close range meant there was no solid target, which points to radar propagation effects.
The researched reading
Ground and airborne radar repeatedly tracked two slow targets that pilots never saw. Bird flocks or anomalous propagation explain it reasonably well, though not perfectly.
| Explanation | Weight | Why |
|---|---|---|
| Something known, misidentified | 30% | Blue Book suggested flocks of migrating birds: October is peak migration across the Mediterranean to Africa, flocks give bright, slow radar returns, and fighters at night would not see them. |
| A known natural phenomenon | 28% | Coastal temperature inversions over the warm Mediterranean cause anomalous propagation, producing slow, persistent false or displaced echoes; airborne radar locks with no visual contact fit this. |
| Genuinely anomalous | 18% | Repeated ground radar and airborne radar locks over three hours, without visual contact on a clear night, were considered important by the Air Force itself; neither birds nor propagation fit all details. |
| Secret human technology | 13% | Soviet or other reconnaissance aircraft probing a US base in Libya in the Cold War, or Allied unscheduled flights, could explain slow, high targets that evaded visual contact at night. |
| A poorly understood natural phenomenon | 6% | Ionised or turbulent air layers occasionally give unusual radar echoes not easily classed. |
| Perception, memory or mind | 4% | The case rests on instruments more than perception. |
| A hoax or fabrication | 1% | An official military radar report is not likely invented. |
Official position: Blue Book found no definite explanation and suggested migrating birds; a later review pointed to radar propagation effects.