Air France Flight AF3532, Coulommiers

Friday 28 January 1994. Air France Flight AF3532 was flying from Nice to London with 24 passengers aboard. The Airbus A320, named Ville d'Amsterdam, cruised at flight level 390, nearly 12,000 metres up. Below lay the Coulommiers area of Seine-et-Marne, about 70 km east of Paris. Visibility ran to 150 to 200 nautical miles.

At 13:14, the chief steward was in the cockpit. He noticed something to the left and called it a weather balloon. The copilot, Valérie Chauffour, at first agreed. Captain Jean-Charles Duboc saw what he first took for an aircraft facing them, banked at 45 degrees, about 45 km away and around 10,500 m up. Soon all three agreed that it looked like nothing they had ever seen.

It began as a dark bell, then became a brown-red lens. Duboc called it an "enormous dark red lens with fuzzy edges." Chauffour saw a "dark brown disc which changed form all the time." Duboc reported no wings, control surfaces, engines or lights. Duboc's estimates of its size ran from about 1,000 m across down to about 400 m.

To the captain it stayed still as the Airbus flew past, sliding from 10 o'clock to 8 o'clock off the left side. Then it was gone. "When leaving it on our left rear, I suddenly saw it become transparent and disappear without moving." Years later he wrote that it "disappeared progressively in 10 or 15 seconds, as if it had dematerialized."

Reims air traffic control passed the report to CODA, the air-defence operations centre at Taverny. CODA wanted a formal report. Duboc hesitated. "As it seemed difficult to testify about such a mysterious phenomenon, I initially refused to write a report."

The military centre at Cinq-Mars-la-Pile started a radar track that ran for 50 seconds, crossing the path of AF3532. It matched no flight plan. The height-finding radar showed nothing. Jean-Jacques Vélasco of SEPRA took up the case, and Dominique Weinstein took formal statements in 1999 and 2000. CODA's analysis ruled out a weather balloon.

The story broke in Paris-Match on 13 February 1997. In March 1997 Duboc met COMETA, a private group of senior defence figures. Their 1999 report gave the object as about 250 m and said the radar track "corresponded in location and time" to the sighting. GEIPAN now rates the file D. Unexplained.

The radar track came from the right, while all three crew saw the object on the left, about 45 km away. Eric Maillot of the Cercle Zététique pointed to the mismatch in 1998 and proposed a Guppy cargo aircraft. Météo-France said a weather balloon had crossed the route about an hour earlier and was already coming down after bursting. In 2007 researcher Patrick Gross concluded that a stationary object on the left "cannot be claimed to be corroborated by a radar track coming from the right side." Vélasco suggested the crew had misjudged the distance, or that the radar had caught a separate phenomenon.

Duboc had his own ideas. Stealth technology creating a false radar image. In 2007 he listed four options, among them an extraterrestrial demonstration and US technology recovered from Roswell.

On 12 November 2007 Duboc gave a statement at the National Press Club in Washington, at a pilots' press conference organised by James Fox. In 2023 Vélasco told Affaires sensibles it was the most remarkable UFO case recorded since the creation of GEIPAN. Duboc has since died. The object remains unexplained.