The El Bosque Air Show UFO

November 5, 2010. El Bosque Air Base, Santiago, home of the Chilean Air Force Academy. The Air Force was changing command, and President Sebastián Piñera and Defence Minister Jaime Ravinet led the ceremony. Then came the flypast. Pillán trainers. The Halcones aerobatic team. Helicopters. Finally F-5 and F-16 fighters. Nobody on the ground noticed anything unusual. The pilots reported nothing.

The object appeared only later. An engineer from the Pillán aircraft factory, next to the base, was playing his footage in slow motion, looking for a frame to use as a poster photo. Something was there. He reported it to CEFAA, the government-backed body that studies aerial phenomena in Chile. In time, seven people who had filmed the show came forward with videos from different positions.

Leslie Kean described a dome-shaped object with a flat bottom and no visible means of propulsion. The rounded top reflected the sun and looked metallic. The underside was darker. It "zooms toward each set of jets at about their height, circles around and zooms back out again." Three passes, within seconds of each other. The Halcones. The F-5s. The F-16s. No sound. No sonic boom, even at Kean's estimated 4,000 to 6,000 mph.

CEFAA's analysts went through the footage frame by frame. Astronomer Luis Barrera said: "The object performed a risky flight maneuver in front of the Halcones from W-E-W, at low altitude." Imaging expert Alberto Vergara said it "moved at a speed far superior to any flying object of known manufacture." The astronomers ruled out a meteoroid, comet, returning space junk, bird or aircraft.

The director, Gen. (ret.) Ricardo Bermúdez, was plain. "At this time, this incident cannot be scientifically explained." In February 2012 he took the case to the International UFO Congress in Phoenix.

Sceptics had an answer. Robert Sheaffer wrote: "Case Closed: this 'UFO' is a flying insect." He argued that the speeds only held "if one knows for certain the distance from the 'UFO' to the camera, which in this case we obviously don't." Astronomer Phil Plait called it "a tiny thing in a low-res video."

Kean consulted entomologists. Elizabeth Arias said: "I would say they were not insects." Mario Elgueta of the National Museum of Natural History in Santiago said "there is no noticeable detail in them to make me think on an insect right away."

In November 2012 two technical reports arrived. They disagreed. Richard Haines of NARCAP concluded that two cameras had recorded the same object, so "at least one of these UAP was not a flying insect near the cameras." Bruce Maccabee found the two most promising videos "did not show the same object at the same time," and judged it "most likely that the objects were small and nearby such as insects."

CEFAA held its ground: "these photos do not show anything which allows for the conclusion that they are bugs." In its files the case remains unsolved. Kean called it "in some ways… more explosive than many of the cases in the book." And everything turns on one question. Did two cameras catch the same thing at the same moment?