TROYES (10) 02.10.2016

On Sunday 2 October 2016 at 21:57, a witness in his 4th-floor flat noticed 7–8 white lights resembling aircraft lights moving rapidly through the sky. One light stood apart, the whole forming a compact triangle. He heard no sound during the approximately 10-second sighting. Only 1 account was collected. GEIPAN considers a Falcon aircraft passing at relatively low altitude, 4,900 m, highly probable, as shown in the attached reconstruction. It says the time and direction match exactly: the UTC track converts to 21:59 legal local time, although the initial account gives 21:57. The source states a closest distance of 3,800 m and flight altitude of 4,900 m. Calculated elevation is 52°, compared with the witness’s 15–30°. GEIPAN considers the difference within the usual uncertainty for a witness lacking ground references such as multiples of a roof’s height. The row of lights was one unusual feature. A Falcon is 20 m long; using altitude and ground distance gives an angular size of 0.19°, about 40% of the Moon’s approximately 0.5°. GEIPAN argues that naked-eye vision can distinguish many lunar details, including craters and maria, even within 40% of its disc, and therefore could resolve the Falcon’s windows, which contrast more strongly than lunar relief. The witness was more accustomed to higher aircraft showing only 1–3 ordinary lights without such alignment. When contacted, he confirmed the approximate angular scale of the complete group as comparable to the Moon. The isolated light above the horizontal row is harder to explain. GEIPAN retains the hypothesis because the other features match closely and aircraft, particularly non-commercial jets such as this one, may have additional lighting beyond standard lights. Misperception or a memory error might also account for it. The absence of sound despite the open window could be explained by south-westerly wind at 15–20 km/h, recorded by Infoclimat, opposing sound from the Falcon to the north-east. GEIPAN also has many cases in which attention to an unusual visual event masks sound perception. Aircraft noise heard a few minutes later probably came from the following aircraft west of the witness, whose sound was carried by the wind (see the two-aircraft reconstruction). The witness did not separately mention the Falcon, despite its presence at the relevant time in his field of view, which further supports identifying it with the UAP. GEIPAN classifies the case A: aircraft observation.