Photographed in Gers, France

On April 17, 2018 at 9:00 PM, a witness is taking a long-exposure photo of the sky pointed at the zenith between the Big Dipper and Leo when he notices a trail that he takes for an ordinary airplane trail. At the same moment, he notices that in his field of vision the ground lights up intermittently for two seconds. Only one testimony was collected for this phenomenon. We show (see the investigation report) that the witness photographed an Airbus A321 making the regular Munich-Lisbon route on flight LH1792/DLH05A. Recognition using an online stellar calibration tool allowed us, first, to identify the star field appearing in the photograph and crossed by the airplane. Second, a superposition of this field with the correctly oriented area of the sky also allowed us to define the observation azimuth and the path axis of this airplane. Finally, a cross-check of this path with those of airplanes passing over the observation area allowed us to identify with certainty the airplane in question. It should be noted, however, that the sequence and synchronization of the white anti-collision wingtip lights of this airplane are abnormal, Airbus aircraft usually "flashing" twice in very close succession at a frequency of one hertz, and not four times or randomly as can be seen in the photograph. The overall conformity leads to the conclusion that this is a malfunction of the lights. The strangeness noted by the witness ("at the same time, I noticed that in my field of vision the ground lit up intermittently for two seconds") is the subject of a different description by the witness following a question from GEIPAN: "my astonishment came when seeing the detail in the photo. It was then that the luminous impression on the ground became conscious to me." The second version is most likely the correct one. The phenomenon (called priming) is classic in the observation of UAPs: an initial strangeness creates an understandable state of arousal (which can go as far as panic) in the witness, which can lead him to associate with this initial strangeness (and therefore increase it) other strangenesses or information that might not even have been perceived (or at least would not have caused concern) in the absence of the initial strangeness. The furtiveness of this lighting and the non-direct perception (observation in the visual field and not in the line of sight) already suggest that this was caused by a local point light source: a car passing by and directing its headlights toward the witness, a neighbor using a flashlight, etc. The additional testimony supports this explanation. The consistency is low: - although a photograph was taken, the original was not provided. The investigator had to reconstruct the angular data with the elements provided, in the absence of precise measurements given by the witness (angular heights, azimuths, angular distance traveled); - no data exists regarding the witness's environment (precise situation, presence of lights, neighbors, roads, etc.) that would have potentially allowed further exploration of the source of the ground lighting (the false second strangeness); - also note that the witness described the second strangeness in the initial testimony differently (and in fact stranger) than the actual awareness he says (afterward) he had of it during the observation. This low consistency is nevertheless not able to prevent the explanation, so much does it impose itself through the other available elements. Consequently, GEIPAN classifies the case as "A": Observation of an Airbus A321 airplane, flight LH1792/DLH05A en route to Lisbon. Strangeness perceived after the fact upon seeing the photo.