SERMUR (23) 06.08.2018

On 6 August 2018 around 22:00, a witness was looking at stars from a hill overlooking Sermur (23). He noticed 5 closely spaced, aligned “stars.” He took a photograph and, on enlarging it, interpreted the 5 light sources as a flat rectangular structure. He described the moving UAP as 5 white luminous rectangles bordered by 5 red points of light. No further accounts were collected. The preferred explanation is an aircraft misidentification (see the investigation report). GEIPAN finds that the UAP’s appearance in the photograph, which may not be published at the witness’s request, strongly resembles an aircraft at cruising altitude recorded during an exposure. The elements are perfectly symmetrical, and the red, white and green colours match aircraft lighting. The exposure lasted 6 seconds. The visible elements, a white line and a red point, repeat 5 times, giving a rhythm of approximately 1 second—the interval used by aircraft anti-collision lights (see the article “An aircraft?”). Brief red anti-collision flashes separated by 1 second match the red points; the white lines correspond to white anti-collision lights. Closer examination shows that the continuous line connecting the white lines and red points is green, matching an aircraft’s starboard navigation light (see the Wikipedia article on aircraft headlights and lights). According to the witness’s information, the UAP moved north to south, east of his position. An aircraft on that path would show its starboard side, consistent with the greenish continuous line. The particular aircraft cannot be formally identified, but international flights from Paris to Africa follow a compatible route. The UAP’s angular displacement during the exposure is about 5°, corresponding to approximately 1° per second, also consistent with an airliner. GEIPAN considers the close match of these features conclusive. The case has moderate evidential strength because there is only 1 witness. The photograph identifies an airliner beyond doubt, although the long interval between receipt of the account and GEIPAN’s processing prevents identification of the specific aircraft. The witness was mistaken in describing a diagonal, downward trajectory. Relative to the stars, the photographed path was approximately parallel to the horizon. GEIPAN attributes this probably to an interpretation based on the photograph rather than the actual sighting, compounded by the late report: the observation occurred in August, but the questionnaire was completed in December. This interpretation error also explains his description of a single flat rectangular structure. His initial description of 5 aligned stars, like those in the photograph, further supports an interpretation error. Had 5 aligned luminous points actually moved together, the exposure would have produced a much more pronounced coloured streak. In conclusion, GEIPAN considers this a slightly unusual case with moderate evidential strength—1 witness but a photograph—and identifies an airliner. The photograph shows regularly repeating elements whose red and white flash rhythm matches airliner anti-collision lights; the angular movement also matches an airliner. The green starboard-light trace and route compatible with a flight departing Paris provide further evidence. The case is classified A: misidentification of an airliner.