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Belgium’s Flying Triangle Wave

Thirty years ago, thousands of Belgian citizens reported mysterious platforms flying silently over rooftops. The Royal Belgian Air Force got involved and cooperated fully with civilian investigators. To this day, however, the origins of these craft remain unknown.

It’s hard to convey the excitement caused by the Belgian UFO wave if you were not following UFO news back in 1989 and the early 1990s. There was no shortage of UFO reports back then, and interest in the phenomenon was at a high. The sightings and photos from Gulf Breeze, Florida, dominated the American scene, wild UFO reports and stories coming out of the old Soviet Union received huge international media attention, and the Mexican video wave took off in 1991. Yet the Belgian wave seemed to top all of these stories for awhile. The reports out of this small country, headquarters of both the European Commission and NATO, received unprecedented coverage, making even the front page of the Wall Street Journal on October 10, 1990, with a story entitled, “Belgium Scientists Seriously Pursue A Triangular UFO.”

The classic triangular-shaped UFO described by hundreds of eyewitnesses during the Belgium wave: sketch by witness used to create reconstruction of the object seen at the top of story. Credit: SOBEPS

There were many reasons for the interest generated by the Belgian wave. One was the quality of the reports themselves, the bulk of which were registered in the French-speaking region of Wallonia. There were no landings or humanoid sightings but lots of detailed multiple-witness sightings of flying platforms moving slowly and silently above rooftops. Shapes varied, but the predominant form was triangular or delta-shaped crafts. Some of the descriptions were so precise that traditional explanations of misidentified natural phenomena or conventional aircraft were ruled out. Instead, stealth fighters and other U.S. secret military aircraft became the favorite explanations suggested by skeptics, but these were quickly ruled out by the Royal Belgian Air Force (RBAF). Another reason for the wave’s importance was that it was carefully investigated and documented by a local UFO organization called SOBEPS (Belgian society for the study of space phenomena).

SOBEPS was formed in 1971 by Lucien Clerebaut, Michel Bougard, and others, and built a small but highly dedicated cadre of field investigators. By the end of the wave in 1993, SOBEPS had collected over two thousand eyewitness reports comprising twenty thousand pages, four hundred hours of audio tapes, and six hundred full inquiries. Five hundred and forty cases remained unexplained. SOBEPS also had the assistance of top-notch scientists, including Léon Brenig, a nonlinear dynamics theorist at the Free University in Brussels, and Professor Auguste Meessen, a physicist from Catholic University at Louvain. Regarding his work with SOBEPS, Dr. Brenig has said, “here is an opportunity where we can apply the scientific method.” Brenig himself became a witness of the so-called Belgian triangle while driving in the Ardennes on March 18, 1990. The whole dossier was eventually published by SOPEPS in two massive volumes, five hundred pages each, entitled Vague d’OVNI sur la Belgique (UFO Wave ver Belgium), published in 1991 and 1994 respectively. Due to financial difficulties, SOBEPS dissolved on December 31, 2007, but some of its members formed a new, smaller organization called COBEPS (Belgian committee for the study of space phenomena) to preserve the archives and work done for thirty-six years.

The two volumes published by SOBEPS entitled, “UFO Wave Over Belgium.” Credit: SOBEPS

A final and key element in the credibility of the Belgian UFO wave was the participation and validation by the RBAF, which showed an unusual degree of openness. As the Belgian wave gained steam, the Belgian Ministry of Defence was deluged with queries from the public and the media. The task fell upon the chief of operations of the air force, Col. Wilfried De Brouwer, who was later promoted to major general and deputy chief of the RBAF. Now retired from the service, Gen. De Brouwer has continued to speak about the wave. He was one of the many international officials who spoke at the famous event at the National Press Club (NPC) in Washington, DC, in November 2007, organized by filmmaker James Fox and journalist Leslie Kean. “The Belgian UFO wave was exceptional and the air force could not identify the nature, origin and intentions of the reported phenomena,” said De Brouwer at the NPC. He also gave a detailed presentation on the wave at the MUFON International UFO Symposium in San Jose, California, in July 2008, and was one of five generals to write an essay in Leslie Kean’s new book, UFOs: Generals, Pilots, and Government Officials Go On the Record.

Although the RBAF scrambled jets on three occasions during the wave, Gen. De Brouwer has explained on various occasions that they didn’t have the manpower or resources to mount a full-fledged investigation of their own, so instead they took the unusual route of cooperating fully with SOBEPS. The radar data was turned to Prof. Meessen for analysis, and Gen. De Brouwer agreed to write the postface for SOBEPS’s first volume when he was still in the service. “I must acknowledge that I somewhat hesitated when SOBEPS asked me to contribute my share to this book,” he wrote. “Indeed, I am not a UFO specialist and, moreover, it is quite delicate for somebody who occupies an official function to put on paper his personal ideas on such a disputed issue. However, I estimate that I would not have been honest towards the SOBEPS if I had refused. The air force always played a fair game on this subject and I regard this postface as a complementary element to the exceptional file written by the people of SOBEPS.”


Although some sightings were reported in October 1989, the first important incident of the Belgian wave took place a month later on November 29 around the small town of Eupen, which is in a region of Belgium near the German border. This initial case put the so-called “Belgian triangle” on the map and led to the start of the RBAF’s involvement. There were both daytime and nighttime sightings, although the latter were lengthier and more detailed. Gen. De Brouwer explained in his essay for Leslie Kean’s book, “a total of seventy reported sightings made on November 29 were fully investigated and none of these sightings could be explained by conventional technology. The team of investigators and I estimate that approximately fifteen hundred people must have seen the phenomenon at more than seventy different locations from different angles during this afternoon and evening.” There were a total of thirteen gendarmes (policemen) who saw the UFO from eight different locations around Eupen. Prof. Meessen summarized the case in SOBEPS’s book:

On November 29, 1989, a large craft with triangular shape flew over the town of Eupen. The gendarmes von Montigny and Nicol found it near the road linking Aix-la-Chapelle and Eupen. It was stationary in the air, above a field which it illuminated with three powerful beams. The beams emanated from large circular surfaces near the triangle’s corners. In the center of the dark and flat understructure there was some kind of “red gyrating beacon.” The object did not make any noise. When it began to move, the gendarmes headed towards a small road in the area over which they expected the object to fly. Instead, it made a half-turn and continued slowly in the direction of Eupen, following the road at low altitude. It was seen by different witnesses as it flew above houses and near City Hall.

In his 2008 MUFON lecture, Gen. De Brouwer provided additional details on this sighting: “The UAP [Unidentified Aerial Phenomenon] emitted repeatedly and simultaneously two red light beams with a red light ball at the spearhead of the beam. Subsequently, the red balls returned to the craft.” There was also apparently a second triangular craft, which made “a forward tilting maneuver, exposing the upper side of the fuselage,” continued De Brouwer. “They [gendarmes] saw a dome with rectangular windows, lighted up at the inside. It then disappeared to the North.” Two more gendarmes saw one of the craft from a monastery nearby; “one is currently the head of the police in that area, he was scared like hell,” added De Brouwer.

Statistical chart of Belgian sightings between October 1989 and September 1990, showing peaks in the November-December period and a second one in April. Credit: SOBEPS

The Eupen incident was followed by many other UFO sightings, including several reported on December 11, 1989. One of the witnesses that evening was a personal acquaintance of Gen. De Brouwer, Col. André Amond, a civil engineer in the Belgian Army. Col. Armond worked next door to Gen. De Brouwer and wrote a detailed report for the Ministry of Defence. Col. Armond was driving with his wife around 6:45 p.m., when they noticed a strange object with flashing red lights. They stopped the car and got out to see it better. “Suddenly, they saw a giant spotlight, about twice the size of the full moon, which approached them to an estimated distance of 100 meters,” wrote De Brouwer, adding that “the colonel’s wife was frightened and asked to leave.” In his report to the Ministry, Armond “ascertained that this craft was not a hologram, helicopter, military aircraft, balloon, motorized Ultra Light, or any other known aerial vehicle.”

Various shapes were reported throughout the wave, including round, rectangular, and cigar-shaped, but the majority were triangular objects. Gen. De Brouwer notes that the differences may also be due to the eyewitnesses’ viewing angles. Researcher Marc Valckenaers listed some of the characteristics of the UFOs in SOBEPS’s second volume about the wave, including: irregular displacement (zig-zag, instantaneous change of trajectory, etc.), displacement following the contours of the terrain; varying speeds of displacement (including very slow motion), stationary flight (hovering), overflight of urban and industrial centers, and sound effects (faint humming to total silence).

Reconstruction of the incredible rectangular flying platform seen by two factory workers on April 22, 1990, described as “an aircraft carrier turned upside down.” Credit: SOBEPS

One of the strangest reports came from two factory workers from the town of Basècles, southwest of Brussels, who saw a huge trapezoid flying platform (330 x 200 feet) just before midnight on April 22, 1990. The object moved slowly and silently, covering the entire factory courtyard. In the SOBEPS report, the factory workers described the UFO as “an aircraft carrier turned upside down.” Despite the science-fiction quality of this sighting, an almost identical report was filed nearly a year later, on March 15, 1991, by an electronic engineer in Auderghem, near Brussels, who woke up in the middle of the night when he “heard a barely audible, high-frequency whistling tone. He looked out the window and saw a large rectangular craft at very low altitude with irregular structures on the bottom,” wrote Gen. De Brouwer.

One characteristic of the Belgian wave was how close the objects were flying above the rooftops, as shown with this flying rectangular platform. Credit: SOBEPS
Another view of the rectangular flying platform above the rooftop and sketch showing where the witness saw it. Credit: SOBEPS


If the Eupen multiple-witness sightings of November 1989 triggered the Belgian wave, the jet fighter scramble incident during the night of March 30, 1990 marked the peak of public interest and global media coverage. The Belgian Air Force had scrambled jets on two prior occasions without positive results. The December 5, 1989 scramble was unsuccessful; when the jet reached the sky, the UFO was gone. Additionally, the December 16, 1989 case turned out to be a false alarm; the authorities quickly determined that it was a laser projection reflected by a cloud layer. Following these two fiascos, the RBAF implemented a new policy that jets would be scrambled only when a sighting was detected on radar and was visually confirmed on the ground by the police.

The SOBEPS team visiting the Royal Belgian Air Force radar facility at Glons: in the center group, left, the Society’s chairman Lucien Clerebaut and right, physicist Prof. Auguste Meessen, next to military officer. Credit: SOBEPS

As put in a preliminary report prepared by Major P. Lambrechts of the RBAF, entitled “Report Concerning the Observation of UFOs During the Night of March 30 to 31, 1990,” the incident began at 10:50 p.m. on March 30 when the gendarmerie telephoned the radar “master controller at Glons” to report “three unusual lights forming an equilateral triangle.” More gendarmes confirmed the lights. When the NATO facility at Semmerzake detected an unknown target at 11:49 p.m., a decision to scramble two F-16 fighters was made. The jets took off at 12:05 a.m. from Beauvechain, the nearest air base, and flew for just over an hour. According to Major Lambrechts’s report:

The aircraft had brief radar contacts on several occasions, [but the pilots]…at no time established visual contact with the UFOs…each time the pilots were able to secure a lock on one of the targets for a few seconds, there resulted a drastic change in the behavior of the detected targets…[During the first lock-on at 12:13 a.m.] their speed changed in a minimum of time from 150 to 970 knots [170 to 1,100 mph] and from 9,000 to 5,000 feet, returning then to 11,000 feet in order to change again to close to ground level.

When Col. De Brouwer showed the computerized radar images of the UFO tracked by the F-16 onboard radar system in a heavily attended press conference at the Ministry of Defence on July 11, 1990, the international media went into a frenzy. Transcripts of the radio communications between ace fighter pilots, Capt. Yves Meelbergs, Lt. Rudy Verrijt, and the Glons Control Reporting Center near Liege, were also released and provide some dramatic moments. The transcripts paint a picture of the jets chasing ghost radar echoes that appear and disappear and then reappear again, but at no time are the pilots able to establish visual contact with the supposed objects. Belgium’s Electronic War Center (EWC) eventually undertook a detailed technical analysis of the F-16 computerized radar tapes, completed by Col. Salmon and physicist M. Gilmard in 1992, and later reviewed by Prof. Meessen.

An F-16 jet fighter of the Royal Belgian Air Force like the ones scrambled on the night of March 30-31, 1990. Credit: Bernard Thouanel

Although some aspects of this case still remain unexplained, Meessen and SOBEPS accepted the Gilmard-Salmon hypothesis that most of the radar contacts were really echoes caused by a rare meteorological phenomenon. This became evident in four lock-ons, explained Meessen, “where the object descended to the ground with calculations showing negative altitude…. It was evidently impossible that an object could penetrate the ground, but it was possible that the ground could act as a mirror.” Meessen explained how the high velocities measured by the Doppler radar of the F-16 fighters might result from interference effects. He pointed out, however, that there was another radar trace for which there is no explanation to date. As for the visual sightings of this event by the gendarmes and others, Meessen suggested that they could possibly have been caused by stars seen under conditions of “exceptional atmospheric refraction.”

One frame from the F-16 onboard radar system showing the UFO lock-on during the March 1990 scramble episode, shown by the RBAF at a famous press conference in July 1990. Credit: RBAF/ Bernard Thouanel

In a 1995 telephone interview, Gen. De Brouwer summarized his reflections on this complex case: “We always look for possibilities which can cause errors in the radar systems. We can not exclude that there was electromagnetic interference, but of course we can not exclude the possibility that there were objects in the air. On at least one occasion there was a correlation between the radar contacts of one ground radar and one F-16 fighter. This weakens the theory that all radar contacts were caused by electromagnetic interference. If we add all the possibilities, the question is still open, so there is no final answer.” De Brouwer took a more detached view of the F-16 scramble episode, however, in his 2008 MUFON lecture and his 2010 essay included in Kean’s book: “The conclusion of the Air Force, therefore, was that the evidence was insufficient to prove that there were real crafts in the air on that occasion.”


The famous color slide of the Belgian triangle photographed in Petit-Rechain in early April 1990. Credit: © Guy Mossay/SOFAM

Seldom has the old saying that a picture is worth a thousand words become more true than in the case of the extraordinary photograph of a flying triangle taken in the small town of Petit-Rechain in April 1990. This color slide became the emblematic symbol of the Belgian UFO wave. It has been published and broadcast in television programs all over the world, and it appears on the cover of the two SOBEPS volumes on the Belgian wave. It’s also one of the most analyzed UFO photos in the history of ufology. During my trip to Brussels in 1995, I had the opportunity to talk at length with Patrick Ferryn, the investigator who researched the case initially and wrote the chapter about it in the SOBEPS book. Ferryn gave me copies of the photo and samples of computer enhancements made by Marc Acheroy, professor of electricity at the Royal Military School, where the image was analyzed by the Signal Treatment Center. The details of how the photo was taken are fairly simple and straightforward.

The photographer, P.M. (who wants privacy, but has fully cooperated with SOBEPS), was a twenty-year-old factory worker, who lived in the small community of Petit-Rechain, near Verviers. He was at home with his girlfriend on the night of either April 4 or 7, 1990 (he can’t pin down the exact date), when his girlfriend first noticed the object between 11:00 and 11:30 p.m. as she took the dog to the courtyard. According to P.M.’s statement to Ferryn, he was alerted by his girlfriend, went outside, and “saw the object practically stationary towards the southwest, at about a forty-five-degree elevation. It consisted of three white round lights on a barely perceptible triangular surface. In the center there was a blinking spot of the same color, or maybe a bit more reddish than the other lights.” P.M. grabbed his camera, a Praktica model BX20 with a 55-200 mm zoom and a “Cokin” 1A 52 mm skylight filter. He shot the last two frames of a roll of 36-200 ASA Kodak color slide film. The UFO then moved slowly towards Petit-Rechain, until it was hidden by the roofs in the village. The entire episode took about five minutes.

The roll of film was sent by mail to a development house offering a special discount, and when P.M. received the slides, he noticed only frame #35 had captured the UFO; frame #36 was entirely black. Ferryn estimated that “the photo was probably taken with a focal distance between 55 and 200 mm, and with exposition time ranging from 1 to 2 seconds.” P.M. showed the photo to his factory coworkers (all of whom were later interviewed by Ferryn), but otherwise didn’t do anything to analyze or commercialize the picture. One of his coworkers knew a local photo-journalist from Verviers, Guy Mossay, who immediately saw the image’s potential value. P.M. sold the photo rights to Mossay for a small fee. Mossay then proceeded to copyright it with SOFAM (Belgium’s multimedia society for visual arts authors).

Skeptics have naturally pointed to the possibility of a hoax with profit motive. However, if that is the case, why did P.M. sell the rights to Mossay for a minor fee? Moreover, hoaxers never supply original slides or negatives for scientific analysis, as was done by P.M. Having checked his background, interviewed acquaintances, and so on, Ferryn noted that “the account of the main witnesses was coherent.” Gen. De Brouwer spent quite a bit of time explaining the details of this case during his MUFON lecture, saying of the witness that, “this guy is genuine, he is a guy who would not fake at all, I can assure you of that.” More importantly, the Petit-Rechain photo has been subjected to more scientific analysis than practically any other UFO photo in history.

When the Petit-Rechain photo is overexposed, the triangular outline of the object appears clearly. Credit: © Guy Mossay/SOFAM

The list of experts and institutions that have analyzed this photo include Prof. Acheroy of Belgium’s Royal Military Academy; Prof. François Louange, an expert in photo interpretation of satellite images for the French space agency, CNES; Dr. Richard Haines, a retired senior NASA scientist and respected UFO researcher; Belgium’s Royal Institute of Artistic Patrimony; and André Marion, a nuclear physicist with France’s National Center for Scientific Research (CNRS), who conducted an analysis in 2002 with improved technology. The technical details of these analyses are too numerous for this article, but suffice it to say that evidence of photographic trickery has never been found. Furthermore, of several efforts to duplicate the photo using a dark cardboard triangular model with holes and light bulbs, only one made by members of the Astrophysics Institute at Liege University somewhat resembled the Petit-Rechain photo. But the luminosity of the spots in the replica was uniform, while those in the original exhibited different shapes and spectral effects. The most recent CNRS study by Dr. Marion confirmed the previous analysis and found, as put by Gen. De Brouwer, a “halo around the craft with patterned structure,” which could have been caused by the object’s “propulsion system” of “magnetoplasma dynamic.” Marion also stated that “it would be extremely difficult to fake such a photograph.”

In the end, it’s almost impossible to guarantee the authenticity of a UFO image. There will always be a difference of opinions, but the verdict in the Petit-Rechain case appears highly favorable. Triangular UFOs were seen throughout Belgium during the early 1990s. Dozens of fuzzy videos and grainy photos were taken, but they were generally not impressive. Petit-Rechain was the great exception.

Note: Since the writing of this article, the photo turned out to be an admitted hoax.


Due to the high credibility of most witnesses in the Belgian wave and their descriptions of a silent, triangular craft being so precise, trying to explain the wave in terms of hoaxes, misidentified natural phenomena, or conventional aircraft seemed fruitless. Therefore, a number of skeptics and aviation journalists focused on trying to prove the hypothesis of secret U.S. aircraft flying over Belgium. A series of candidates were proposed, from the Airborne Warning and Control System (AWACS) to secret airships, from the F-117A stealth fighter to some other revolutionary U.S. secret military aircraft such as the alleged TR-3A Black Manta. First, you have to ponder why the U.S. would conduct tests of their most-secret aircraft in such a highly populated area like Wallonia, which is not only a U.S. ally, but also headquarters of the NATO alliance. Gen. De Brouwer put it bluntly in a 1991 interview with the French magazine, OVNI Présence: “Why would the Americans conduct tests here in Europe, without permission and with the risk of having an accident that could create a diplomatic incident on a global scale? This doesn’t involve only Belgium, but NATO, where its concept itself could be put in question. I don’t believe that the Americans could take such a risk, it’s evident.”

Major General (Ret.) Wilfried De Brouwer, who was the Royal Belgian Air Force point man for the UFO wave, during his trip to Washington, DC to participate at the National Press Club event in 2007. Credit: Bernard Thouanel

Guy Coeme and Leo Delcroix, the two Belgian Ministers of Defence during the wave, denied emphatically the theory that the UFOs were actually U.S. aircraft and based their denial on official inquiries with the U.S. Embassy in Brussels. In a 1993 letter to French researcher Renaud Marhic, Minister Delcroix wrote: “Unfortunately, no explanation has been found to date. The nature and origin of the phenomenon remain unknown. One theory can, however, be definitely dismissed since the Belgian Armed Forces have been positively assured by American authorities that there has never been any sort of American aerial test flight.” A declassified 1990 document from the U.S. Defense Intelligence Agency (DIA) entitled, “Belgium and the UFO Issue,” supports Delcroix’s position. After describing the basic events of the wave that had transpired up to that point, the unnamed U.S. official wrote at the very end of this memo: “The [U.S. Air Force (USAF)] did confirm to the [Belgian Air Force] and Belgian [Ministry of Defence] that no USAF stealth aircraft were operating in the Ardennes area during the periods in question. This was released to the Belgian press and received wide dissemination.”

Thirty years have now passed since the Belgian UFO wave, and no new significant evidence has been produced to prove that the sightings were caused by secret military aircraft. The reported cases remain unexplained. It seems certain that something massive and technologically advanced flew over Belgian territory during the 1989-93 period. Why and who was behind it are questions that remain to be answered. A suitable conclusion, for now, is to repeat what Gen. De Brouwer wrote at the end of his famous postface to the SOBEPS’s first volume: “The day will come undoubtedly when the phenomenon will be observed with technological means of detection and collection that won’t leave a single doubt about its origin. This should lift a part of the veil that has covered the mystery for a long time. A mystery that continues thus present. But it exists, it is real, and that in itself is an important conclusion.”

The author (left) with SOBEPS’ chairman Lucien Clerebaut at the Society’s headquarters in Brussels in 1995. The map in the background shows the locations of sightings in Belgium. Credit: Antonio Huneeus

A version of this article originally appeared in Issue #5 (December/January 2011) of Open Minds UFO Magazine. Back issues can be found here.


Antonio Huneeus

Open Minds Investigative Reporter J. Antonio Huneeus has covered the UFO field from an international perspective for over 30 years. His articles have appeared in dozens of publications in the U.S., Latin America, Europe and Japan. He was also the co-author of the Laurance Rockefeller-funded “UFO Briefing Document – The Best Available Evidence” and edited the book “A Study Guide to UFOs, Psychic & Paranormal Phenomena in the USSR.” Huneeus studied French at the Sorbonne University in Paris and Journalism at the University of Chile in Santiago in the 1970s. He has lectured at dozens of UFO Conferences all over the world and been interviewed by many media outlets including The Washington Post, the Sy-Fy and History Channels, Nippon-TV, etc. He received the “Ufologist of the Year” award at the National UFO Conference in Miami Beach in 1990 and the “Courage in Journalism” award at the X-Conference in Gaithersburg, Maryland, in 2007.

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