The Belgian UFO Wave

On the evening of 29 November 1989, two gendarmes near Eupen in eastern Belgium reported a large, flat triangular object with bright lights that moved slowly and silently. Many other reports came in from the same region that night. Over the following months, hundreds of people across Belgium described similar objects, usually triangles with lights at each corner and sometimes a red light in the centre.

The civilian research group SOBEPS (Société belge d’étude des phénomènes spatiaux) collected and investigated the reports. Unusually, the Belgian Air Force shared information with the group and responded to requests for help. Military and civilian observers organised watches, and the government allowed the Air Force to try to identify the objects.

The most famous night came on 30–31 March 1990. After ground radar stations reported unidentified contacts and police officers on the ground reported lights, two F-16 fighters were scrambled. Over roughly an hour, the pilots’ radars briefly locked onto targets several times. The targets appeared to change speed and altitude with extreme and abrupt accelerations, then disappeared. The pilots reported no clear visual contact with any object.

The main evidence is the large number of witness reports, many from police officers, which SOBEPS gathered and published in two large volumes. The reports vary in shape, size and behaviour. Some describe objects hovering at low altitude, while others could plausibly refer to aircraft or helicopters.

The F-16 radar data from 30–31 March 1990 was presented at a press conference in July 1990 by Colonel (later Major General) Wilfried De Brouwer of the Belgian Air Force. The accelerations recorded would have been impossible for any known aircraft. That is part of why many analysts concluded they were not real objects but false readings from the radar.

A photograph taken at Petit-Rechain in April 1990 became the iconic image of the wave. It shows a dark triangle with lights at its corners and was studied for years. In 2011 the photographer admitted on Belgian television that it was a model he had made from polystyrene and photographed as a prank.

The Belgian Air Force did not claim to have identified the objects. De Brouwer said publicly that the Air Force had been unable to explain some of the observations. He also stated that no known aircraft, including American stealth aircraft, had been flying at the times reported. The United States denied that its F-117 stealth fighter had flown over Belgium during the wave.

Later technical reviews of the F-16 data attributed the radar locks to spurious echoes. These can be produced by atmospheric conditions such as temperature inversions, or by interference and the radar’s own processing. That explains why the targets moved in physically impossible ways and why the pilots never saw anything.

Sceptics argue that the wave was a social phenomenon. Once the story of the flying triangles appeared in the press, ordinary aircraft, helicopters, ultralight aircraft and bright stars were more likely to be reported as UFOs, and expectation shaped what people described. The admitted Petit-Rechain hoax shows how powerful a single striking image can be in such a climate.

Researchers who defend the case, including SOBEPS investigators, reply that many reports came from police officers who described low, slow, silent objects at close range, which aircraft and stars do not explain well. Others have suggested secret military aircraft or blimps, but no evidence has confirmed these proposals, and they do not account for the number and spread of sightings.